Your most frequently asked questions… answered.
Editor’s notes (2019)
The FAQ and discussion below has been mildly edited to eliminate typos, make it clearer who the authors are and which boats they themselves have (by hull number and boat name if known). Wherever possible alternative (i.e. current) references to products & suppliers are provided.
The bulk of this FAQ was originally generated as a Q&A in the period 2005 – 2015. In this period Lester Helmus acted as a clearing house for questions and responses, but some respondents would also write direct to each other, hence some of the overlapping answers you see in the FAQ. In places there are 2019 and subsequent comments, drawing either on my own experiences, or from other Corbin 39 owners and sources, including our Corbin 39 Group on Facebook. More comments are most welcome and this FAQ will inevitably grow.
We have attempted to contact all contributors to the 2015 version of the FAQ. All responses have been most supportive, thank you. If you are a contributor who has yet to respond please contact us.
As will be apparent there are multiple viewpoints on some topics. Sometimes, but not always, this can be traced to differences in arrangement between the boats of the various authors. Some of the topics raised are not so much a Q&A, as simply being a statement of why a particular owner thought something was a good idea, which of course it may not have been at all. Make your own mind up.
If you have further comments or suggestions on any of these questions, or wish to pose new questions, or describe various issues you have faced and/or overcome, then please contact us either via the Facebook Group or via the Website.
[Remark as of November 2019: Quite a lot of the links to drawings & photos are not yet reinstated due to workload. However I also know quite a few of the relevant images have gone astray. You may find the relevant photos in the individual boat’s entry. Please email us if you have any of the missing photos, drawings, etc.]
HULL and DECK
“What Sealant Do You Need?” by Don Casey. In every Marine Center you will find an array of different sealants and caulks sufficient to make your head spin. With so many choices, how do you know which one you need? It is not as difficult as you might think. Virtually all modern marine sealants fall into one of just three types, each with specific characteristics that make it the best choice for some jobs and unsuitable for others. Selecting the right sealant is essentially a matter of identifying the materials you are wanting to seal–specifically if any component is plastic–and of determining the likelihood of ever needing to separate these components. If neither component is plastic and if you want to preserve your ability to disassemble the joint, use polysulfide. Polysulfide is the most versatile of marine sealants. It is a synthetic rubber with excellent adhesive characteristics, and you can use it for almost everything. As a bedding compound it allows for movements associated with stress and temperature change, yet maintains the integrity of the seal by gripping tenaciously to both surfaces. It is also an excellent caulking compound since it can be sanded after it cures and it takes paint well. However, the solvents in polysulfide sealant attack some plastics, causing them to harden and split. Specifically, you must not use polysulfide to bed plastic windshields or plastic portlights–either acrylic (Plexiglas) or polycarbonate (Lexan). Don’t use it to bed plastic deck fittings either, including plastic portlight frames. Plastic marine fittings are typically ABS or PVC, and polysulfide will attack both. If you know that the plastic fitting is made of epoxy, nylon, or Delrin, you can safely bed it with polysulfide. Below-the waterline through-hull fittings are in this group, but when there is any doubt, select an alternative sealant. Polysulfide adheres well to teak (a special primer improves adhesion), and is unaffected by harsh teak cleaners, making it the best choice for bedding teak rails and trim. The black caulking between the planks of a teak deck is invariably polysulfide. For this application, a two-part polysulfide gives the best results. Polysulfide is the slowest curing of the three sealant types, often taking a week or more to reach full cure. Because it will adhere to almost anything, polysulfide has a maddening propensity to get on everything, so neatness is called for in using this sealant. Polysulfide sealants will have polysulfide printed on the package, or sometimes Thiokol–the trademark for the polymer that is the main ingredient of all polysulfide sealants regardless of manufacturer. If you want the two components to be joined together permanently, use polyurethane. Think of polyurethane as an adhesive rather than a sealant. Its grip is so tenacious that its bond should be thought of as permanent. If there seems to be any likelihood that you will need to separate the two parts later, do not use polyurethane to seal them. Polyurethane is the best sealant for the hull-to-deck joint. It is also a good choice for through-hull fittings and for rubrails and toerails, but not if rails are raw teak because some teak cleaners soften it. Like polysulfide, polyurethane should not be used on most plastics–acrylic, polycarbonate, PVC, or ABS. The cure time for polyurethane is generally shorter than polysulfide, but still may be up to a week. For bedding plastic components or where insulation is desirable, silicone is the default choice. Calling silicone a sealant is something of a misrepresentation. It is more accurate to characterize it as a gasket material. If you accept silicone’s adhesive abilities as temporary, you will find it is the best product for a number of sealing requirements. It is the only one of the marine sealant trio than can be safely used to bed plastic. It is an excellent insulator between dissimilar metals–use it when mounting stainless hardware to an aluminum spar. It is the perfect gasket material between components that must be periodically dismantled–beneath hatch slides, for example. Silicone retains its resilience for decades and is unaffected by most chemicals, but it should not be used below the waterline. Because it depends upon mechanical compression to maintain its seal, silicone is not a good choice for sealing hardware on a cored deck. Exposed silicone is a magnet for dirt and repels paint, so never fillet with silicone, and don’t use it on any surface you plan to paint. Silicone sealants typically set in a few minutes and reach full cure in less than a day. For an adhesive seal of plastic components, select a silicone/polyurethane hybrid. An adhesive sealant maintains its seal even when stresses pull or pry the bedded components apart. The sealant stretches like the bellows joining the two sides of an accordion. This accordion effect can be especially useful for plastic portlight installations where the portlights are captured between an inner and outer frame. Although silicone has amazing elasticity, its lack of adhesion means any expansion of the space between the frames is likely to cause the seal to fail. Either polysulfide or polyurethane would provide a more dependable seal, but polysulfide is certain to attack the plastic, and polyurethane prohibits any future disassembly. The answer to this dilemma is a hybrid sealant–part silicone and part polyurethane. Marketed by BoatLife as Life Seal, this mixture promises a longer-lasting seal for portlights and other plastic fittings where compression of the sealant cannot be assured. For more information about sealing and bedding, consult Sailboat Hull & Deck Repair by Don Casey.
We are planning to paint the deck and we were wondering if anyone can advise us regarding the paint, non-skid areas and the cracks. We want to sand the actual deck pattern and put normal anti-slip (it is already like this in the hatches area). Any advice, especially regarding the cracks on the deck? Thank you! Best regards, Cristina Mandras (#113, Sunrise).
a. Cristina, I can tell you what I did, but it did not really eliminate the cracks. I used a dental pick and acetone to clean and flush the cracks on the deck. I then filled them with penetrating epoxy, which, after the epoxy cured, did not quite bring them flush to the deck. As a cosmetic solution, it was a failure, although I felt like it improved the integrity of the deck. I then lightly sanded and painted the decks with a two part polyurethane paint. In the non-skid areas, I put one coat of paint, which gave them a nice appearance without significantly reducing the non-skid. In the smooth areas, I put two coats of polyurethane. When I was done, it looked pretty good, but after a couple of years, the cracks were clearly visible again. So, I guess I failed. I think your approach of sanding off the deck pattern and putting normal anti-slip is a good one. At least the cracks would be covered in those areas. I don’t know how you get them to totally go away in the smooth areas. Good luck! Bill Gifford (#078, Perpetua).
b. Respectfully and sight unseen, I would not sand the non-skid deck pattern ! I think the existing contrast between ” smooth & non skid ” gives the deck character ….. Why just not re paint over the non skid deck pattern ?? Cheers, Frank Bryant (#186, Visitant).
c. Hello Cristina. We are Harry and Jane aboard Cormorant, hull #144. We have been living aboard since 1997 and have been sailing west around, via the Panama and Suez canals, since then. We are now in Gibraltar (9/2011) and planning to cross the Atlantic this winter. We just had some other Corbin owners aboard (H2OBO, Branko and Maggie) last night and showed them our deck, so you might be able to get another opinion from them. We used a product that has been 100% satisfactory.
Our molded in non-skid was slippery and dangerous, but we didn’t want to spend all the serious money and time to remove all the deck hardware and paint. Not only was our deck slippery, it also looked “tired” and some areas, especially in the curves of the mold, had gelcoat cracks. We were in New Zealand at the time and saw the product,”KiwiGrip” on another boat. It looked good, they loved it, and we figured it was worth a try. This was in 2005. We bought two 4-liter tins of “cream” colored paint. It also comes standard in a light grey and a blue, but the cream is a perfect blend with the Corbin brownish decks.
To begin, we washed all the decks thoroughly, sanded all the areas we wanted to paint–very lightly! We spent only about 4 hours sanding. We did not grind down the old non-skid at all. After sanding, we washed again and then carefully taped all the areas where we wanted the non-skid. This took the longest time, because of all the curves, but it is important in getting a nice looking job done. In a couple of areas where there were cracks or where we had removed deck hardware and had unsightly patches, we just continued the paint without stopping it at the molded in edges. Then we were ready to apply. All this took less than one day.
Kiwi-Grip is a water-based paint, so it can be shipped and is easy to use and to clean up. It comes very thick, and it is put on thick. It is best to do with 2 people, one to glob the paint out of the can and spread it thickly with a brush. The other comes along behind with the texture roller (supplied with every can) to create the surface. There are clear directions on the can and they should be followed. It dries quickly, so they say to do smaller areas at a time. They also say to remove the tape right away and not to let the paint dry first. This is important.
We did our entire boat in two days, and the only reason it took 2 days instead of 1 is that we thought it would be nice to have half the boat to walk on while the other half was drying. It dries right away to walk on, but then it continues to dry and bond to the deck for about a week. We put ours on in 2005 in New Zealand, and since then we have sailed to Australia, Indonesia, Malaysia, Thailand, Indian Ocean, up the Red Sea, and across the Med. Just a few months ago, we bought some in Italy (found it searching chandleries on-line. Probably the company could help if you contact them via the web) and re-did the cockpit seats and a deck area where we had removed an unused water fill deck plate. It goes on easily over the old paint and sticks well. We could only buy white in Italy, but going to the Kiwi-Grip website we contacted the owner and he told us how much of what tint to add for a match. Unless you look closely you can’t tell which is new and which is old. (Actually the old is now a little flatter, but it is still providing excellent grip–see the foredeck photo. One side is renewed, the other original). Not a single crack has come through after 6 years, and we put it right over the cracks without digging them out and re-filling them. None of the paint has peeled off, cracked, or blistered. See cockpitseatnew.jpg, foredeckoldandnew.jpg, pilothousetopold.jpg
We never expected such an inexpensive and easy job to be as attractive and long lasting as it has been. In another few years, we might put another coat on all the decks, but we’ll just wait until it needs it. We have attached a few photos so you can see what it looks like. It is hard to get good deck photos because of the color and the shadows, but you should get the idea. This is the worst it looks because we were leaving Almerimar Marina to head to Gibraltar, and the air there makes the decks very dirty. Harry and JaneHungate, (#144, Cormorant).
d. The reason for the cracks on the deck is that the gelcoat is thicker in the area of the antiskid due to the diamond pattern which tends to gather more gelcoat. Thick gelcoat tends to crack. The good thing is it is only surface cracks and is not structural. If you sand the gelcoat and refinish the surface with paint using sand as an antiskid, like it is usually done, it should solve the problem. I wish you good luck and a great trip. You bought yourself a great boat. Make sure the painter does not only fill the cracks and paint over them. The gelcoat has to be sanded down some. Not necessarily to the fibre, but down some. Have a wonderful day. Marius Corbin.
e. Hello Mr. Corbin, Everyone in the yard and in the marina admires our boat. But no one loves her like we do 🙂 I am supervising the painters every day; I will be careful for them to sand as much as necessary. We are in Valencia, Spain and the workers in Spain are not as good as we would want. Best regards, Cristina.
When it rains we have water dribbling down the post which supports the mast. The mast rests on a bronze metal plate(step) with hinged U-shaped stainless line ‘keepers’. Then, the bronze plate rests on a 2 inch thick teak spacer. The teak spacer rests on a on a stainless plate, which rests on the deck. Where can the water be getting by? Probably, at the thru deck fasteners and/or the thru deck wiring. Does someone have a drawing or photo, with the mast unstepped? Lester, here are the photos of the mast base, Mast Base 1 Mast Base 2 . I really worry about it wetting the deck core. None of the other openings or fastener holes were cored with thickened epoxy in the rest of the boat deck. Wow! Too bad! So what is under this 3 layered mast support is a mystery to me. Yes, delamination of the deck would be an expensive problem to solve. Also, I would like to re-bed the fasteners and epoxy core of all openings on the deck. Does the vinyl interior roof material have to be removed to get to the nuts in order to remove the bolted items on deck? Tim Baggett, (#154, Brillo del Sol).
a. Tim, in my case, a metal plate is welded to the stainless steel compression post that supports the mast, inside the boat. Perhaps there is NO sealant between your deck plate and deck OR NO sealant between your mast step and deck plate or [NO sealant] at the deck plate mounting bolts ………….. ??? don’t know man !! See a photo of my arrangement ..mast step Cheers …….Frank B., (#186, Visitant).
b. Tim, First, you want to remove the overhead liner covering any thru deck fasteners or nearby vent holes, such as a dorade vent. Second, you want to wet the entire deck area near the mast base to see the true source of the leak or leaks. Third, the mast may have to be removed. Fourth, the keepers should have no effect on leakage thru the deck. Fifth, The water is coming thru at the deck fasteners and/or the deck wiring, probably. Lester H. s/v (#010, Insouciance).
c. Tim, this is an unusual thing: to have a teak spacer between the mast step and the deck. The spacer was added, probably, because the stays were too long or the owner wanted the boom to be higher. I would think that the leak originates at the weathered teak (we can see cracks in it on the pictures), going to the bolts, and then following the bolts to the inside of the boat. It is very hard to seal any wood and metal together permanently. Wood and metal expand and contract, with temperature changes, at different “rhythms”. If the spacer could be replaced by aluminium it would be weather-tight for a longer time. The deck under the SS plate is not cored and you should not worry about it rotting. The bolts are thru bolted and it should be visible from inside the boat that one of them is leaking. Hope that helps and have a great day. Marius Corbin
Photos of typical mast bases below. The first two photos are of the teak spacer version which are the subject of the question. Click on them to open with more detail.
Please also cross-reference to the FAQ entry on Keel Repairs as there is information in that FAQ entry which is equally relevant to Rudder & Skeg Repairs.
Here is a 2021 article on Keel & Skeg Repairs that was collated in 2021:
– photo gallery associated with repair of #086, “Stella”, formerly “Jack Iron”
– photo gallery associated with repair of #135, “Petit Chantier”, formerly “Necessity”
– photo gallery associated with repair of #174, “Anakena”
The entries below were collated up until 2019.
The skeg on my boat got hit and has some movement….cracking at the skeg – hull joint and the rudder does not turn all the way to the right. I think the rudder post may have a bend. Do you know anyone who has any experience in how to best pull out the rudder post, as well as in reinforcing the skeg. Bill Swales. (#042, Blondie Too)
a. Dear Bill, I presume your boat is out of the water! If the rudder shaft is bent it sounds as though it might be close to where the skeg joins the hull. To remove the rudder, if the boat is sitting on its cradle, you will need to dig a hole below the rudder, maybe as much as 3 feet deep, depending on the shaft length inside the boat. The rudder may be quite heavy, depending on whether it is filled with foam or a more solid fibreglass mixture. If it has the standard 1.5″ diameter shaft then it is pretty heavy on its own. The shaft should also have a web of stainless flat bar, or other shapes, inside the rudder structure to counteract the torque on the rudder. The photos show: the Corbin drawing with location of rudder, shaft and skeg (see below) ; my drawing of the rudder internal steel structure (see below) ; and a photo of the rudder internals, with plywood fitted to stainless flatbar to improve cross-sectional curvature (below) . To remove the rudder you will need to remove the metal tiller arm inside the boat and any collars, plus loosen the stuffing box nuts. If the shaft is bent it may help to remove the stuffing box completely from the support platform as you will then have a larger diameter hole to allow a non-concentric shaft to be removed. Outside, you will need to unbolt the heel fitting. On my boat, Hull #50, it is a bronze fitting held with 4 or 6 slotted head machine screws that clamp the fitting around a reduced size section of the skeg. Be prepared to support the weight of the rudder as the heel fitting is removed! I had to bend my rudder shaft back into a straight line after I got it back from the welding shop as the heating had caused distortion. This was before the rudder cheeks were installed so it was a somewhat easier job. I used a heavy section I-beam and pulled the rudder shaft onto it with large C-clamps. I had a thin piano wire stretched along the shaft to show when it was straight. It required “overbending” as there was some spring back after the clamps were removed. The attachment of the skeg to the main hull was probably done in one piece during the initial moulding. It would appear to be a potential area of weakness. When I drilled out for the original installation of the shaft there was a solid, blue, thickened resin filler material in the centre. To reinforce the area for a repair one method could be by embedding stainless rods by drilling from immediately above, provided you can get access to the area. Grinding back on each side of the skeg/hull area would allow epoxy and fibreglass patches to be added. A heavy roving or unidirectional fibreglass (Liasil) may be suitable. This may be where a naval architect should be consulted. Good luck. David Salter “#050, Opportunity” located in Bath, west of Kingston, ON .
b. Hello Bill. How are you? How did you damage your skeg? Did you hit something or just by using it. Could you send me pictures. When you knock on it with a hammer, does the skeg feel soft or solid? Where are you located? And what is your hull number? Maybe I can help you. [edit: GD was the yard manager at Corbin les Bateaux]. Best regards, Gaetan Duchesne, (#165, Therese Vincent).
Is your mast compression post sliding aft?
[2019 edit by DS : The premise of this issue as described below is not entirely correct, and best I explain this up front. In the mk1 there are two possible mast and compression post positions. The fwd mast position was intended for use with the ketch, and the aft mast position was intended for use in the cutter/sloop. Subsequently the mk2 design revision adopted the fwd mast position for the sloop/cutter, in combination with the bowsprit, so as to resolve the weather helm that affected some of the mk1’s. Therefore the issue of the mast compression post sliding aft – as described below – can in principle affect the mk1 ketches as well as the mk2 cutter/sloops. Remember also that some of the mk1’s were completed after this weather helm issue was understood and so in fact adopted the fwd mast position.]
I’ve been hard at work below decks on hull #145, Luff Shack. Since I purchased the boat this past Spring, I was kicking around shimming the compression post, once the rig was lowered, to address a slight depression in the deck around the mast step. I knew that the deck was solid fiberglass in the region of the compression post, so it wasn’t a wet deck core issue. I just didn’t like the little puddle that appeared right behind the mast step after a rain or heavy morning dew. The depression would only get worse once the boat is fitted with a hydraulic backstay adjuster. The 2-1/2″ diameter schedule 40 stainless steel compression post has a welded deck flange that has the same dimensions as the cast aluminum mast step/halyard organizer. At the bottom of the post, a single 1/2″ diameter stainless steel bolt passes thru both the compression post and an 8″ tall piece of 3″ diameter stainless steel schedule 40 pipe that acts as the post socket. The socket itself is welded to the 1/4″ thick stainless steel baseplate weldment.
So, to fix the deck depression, I pulled the compression post to install some shims in [under?] the post socket. Upon closer examination of the compression post mounting socket, I realized that it was going to take a bit more than a few shims. As I cleaned up the bilge sump directly behind the compression post mounting area I realized that what I thought was sloppy fiberglass tabbing was actually distortion of the thin fiberglass tabbing due to the compression post mounting area shifting backwards about 3/4″. What happened???
When the [original, mk 1] boat was originally designed, the original location of the mast/compression post was on top of the fiberglass laminates that capped the lead ballast. This presented a nice flat surface for the compression post to sit on. Once the mast and chain plates were moved forward on later Corbins, the mast step now intersected the leading edge of the fiberglass keel laminates. The leading edge of the keel has a pronounce swept back angle, so the downward force of the mast resulted in a secondary force aft and down (down the hill so-to-speak). This arrangement is not unique with the Corbin 39. My previous boat also had the keel sited forward of the lead ballast in the region of the fiberglass laminates that defined the leading edge of the keel sump.
The reason why I found that the compression post keel sump reinforcement shifted aft was due to poor surface preparation of the primary hull laminates, poor material selection used in the keel sump reinforcement, and inadequate surface area/total number of plys of the fiberglass tabbing to handle the thrust loads. Luckily the bond of the fiberglass tabbing was so poor that I was able to literally pry the entire structure out of the leading edge of the keel cavity. I was left looking at shiny (read un-sanded) fiberglass hull laminate and a total of 12 layers of 3/4″ thick mahogany plywood packing that was cut to fit the bottom of keel sump prior to capping off with several layers of fiberglass for the compression post to land on. It is also worth noting that once the compression post keel mount shifted aft, water that found its way aft from the chain locker to the keel sump ended up completely saturating the mahogany packing material making a bad situation even worse. The upcoming repair will find things better than new due to proper surface preparation, epoxy resin, a proper laminate schedule and the elimination of any wood in the compression post mounting area. Here is a sketch that will help you, Compression Post Support .
Here is an outside view of the keel in the compression post step area, Outside View . Note the 2 holes. The upper one is just above the keel sump floor behind the step prior to the tear out of the wet plywood. The lower hole is about 2″ above the polyester resin fill that was found at the bottom of the plywood stack. Once the glasswork is done in the spring, this will be the new elevation of the keel sump. The lower hole will be finished with a 1/2″ bronze flush thru hull fitted with a threaded cap. The cap is removed during winter storage so that any water that comes aboard can drain away rather than accumulating and freezing. This is a common feature on wooden boats, called a garboard (plank) drain plug. The upper hole will plugged with new laminates.
So if anyone finds trouble with a sagging deck or maintaining rig tension, a good look in the forward bilge at the compression post step might be in order. I hope that the chainplate knee laminates continue to hold! Jeff Shutic (#145, Luff Shack).
a. My Corbin 39 is hull #101, an original Corbin with the mast compression post sitting flat on top of the encapsulated lead ballast. Sounds like moving the mast forward on the Mk 2 was not well thought out at the factory. Jeremy P. (#101, Two Pelicans).
b. A2b: Great post – I don’t have the problem but I will watch for it happening. John Gleadle (#181, Spinnaker).
c. I too had the same problem when I first bought the boat. I ended up extending my Compression Post almost 2.5 ” and by making a much larger and a beefier flange ( 1/2 ” SS ) at the top of the post, to spread the deck load more. In my case, there was a large SS saddle c/w short sleeve that held the bottom of the post in place. Also, I ended up making longer all 8 of the deckside turnbuckle bolts in order to gain that 2 1/2 ” without redoing the rigging. Lastly, I had a close look, in the bilge, at the fiberglass around the post and it looked fine to me.
Thanks again. Damn!! I miss that boat ……. Frank Bryant s/v #186, Visitant
Please also cross-reference to the FAQ entry on Rudder and Skeg Repairs as there is information in that FAQ entry which is equally relevant to Keel Repairs.
Here is a 2021 article on Keel & Skeg Repairs that was collated in 2021:
– photo gallery associated with repair of #086, “Stella”, formerly “Jack Iron”
– photo gallery associated with repair of #135, “Petit Chantier”, formerly “Necessity”
– photo gallery associated with repair of #174, “Anakena”
The entries below were collated up until 2019.
I am seeking information to assist a keel sole repair: (A) What material is the sole of the keel and how has it been joined with the rest of the hull? (B) What is the best strategy for repair, especially: what should I use to fill a cavity? Background: When we surveyed my Corbin, we noticed damage to the sole of the keel. No information was available as to the type of damage or when it happened, but by the looks of it this may be many years old grounding damage. I have attached two images: (1) an overview showing the crack at the leading edge and the “cavity” at the stern See Pic 1: Overview and a close-up of the stern damage See Pic 2: Closeup. Forward, I think the crack around the edge suggests that the sole was not laid up with the hull but cast separately. Aft, probing with a screwdriver dislodged a few walnut-size chunks of material, almost like gravel, and this left the white spot that is visible in the photo. No fibers are apparent at that spot. Since this was pre-purchase, we refrained from probing more vigorously. Boris S. (#131, Two Crows, previously Phoenix).
a. I have one of the early Corbins and I’m still building it. Nearly finished though. The Corbins were laid up in two longitudinal halves. Then the two halves were lifted together and glassed on the inside to form a single structure. In my understanding there were no old or new hulls. There was but a single hull mold from which all the Corbins were made. There was, however, a fire at the factory which destroyed the deck molds . So today you will see two configurations , for example, of the pilothouse, the old and the new. Since the hull is one piece there is no separate keel. You will not find a line where the keel attaches to the hull. No keel bolts or anything like that. The ballast is internal. It was placed in the bilge from the inside of the hull. It was glassed in place and covered over with fiberglass. In looking at the photograph of the underside of the keel I believe I can see the line down the middle where the two halves of the hull were put together. This would mean that I am looking at fiberglass, with the gelcoat having the barnacle growth attached. No problem here. Some epoxy or acrylic filler material should solve the problem. If, however, I am looking at exposed lead, and I’m suggesting this because I don’t see a radius where the side of the keel turns to the underside, then you will need to glass the underside of the keel. In reviewing your note i find that I failed to address the issue of the walnut size chunks you’ve extracted. This has me puzzled. I don’t believe this is fiberglass. Is this lead that has been in touch with salt water and it’s corrosive effects? If so how extensive is it? Until you’ve made a determination on these issues it’s pretty hard to suggest a solution. Sincerely, Richard Bakker= , s/v no name yet. (subsequently #008, Stingray).
b. The keel and the hull were built and laminated together, and so is the bottom of the keel. The center of the hull, including the keel, had additional layers put in and in order to do so, and since the back end of the keel is so narrow, we had to fill the aft end with putty (about 2 feet). Additional layers were then put in. Therefore, the aft end of the keel is not structural and is considered sacrificial. Consequently, when damaged, you only need to fill the damaged part with putty and cover the repair with a couple of layers of fiberglass. The bottom should be repaired using alternating layers of 24 ounce woven roving and 1.5 ounce mat, starting laminations with mat. There are many layers on the bottom and you only need to replace whatever was damaged. But, putting too much is better protection for future groundings (I know, I know, you never ground…). Personally, I would put a minimum of 10 layers of alternating mat and roving and finish with 2 layers of mat. At 1/32 of an inch each you should have 1/4 to 3/8 of an inch thick. The more, the better. Hope the above will be of some help, and have a wonderful day. Marius Corbin
c. I’m assuming that the photos you provided are of the bottom of the keel… Perhaps Marius can elaborate further on the building process, but it appears to me that after the hull is removed from the mold, the keel void is liberally lined with a filler before the lead keel is dropped in. The yellowish-orange stuff at the centre of the keel damage is probably the filler, and I’m guessing that whatever caused the damage knocked out a bit of the filler. To repair the voids you will need to fill with a resin/filler mix – you could even use finely chopped fiberglass to thicken the resin. Since you will be filling something upside-down, there will be a tendency for the filler to spill out. Get some heavy cardboard and shape it so it can catch the filler and keep it in the hole. To do this you may have to clamp the cardboard in place across the vertical sides of the keel, so the cross section of the cardboard is a U. Put a plastic drop cloth on the inside of the cardboard and you will have no problems removing it after the filler has cured! Obviously you must sand the surface of the repair area and clean it so everything bonds well. Once the filler has cured, grind down the vertical sides of the keel to about 12 inches above the bottom of the keel. Clean with acetone and cut fiberglass cloth to complete the repair. The cloth should be: (1). a piece just wide enough to span the horizontal bottom of the keel, (2). a piece that covers the bottom of the keel and goes 3 inches up either side, (3). a piece that covers the bottom and goes 6 inches up, (4). a piece that covers the bottom and goes 9 inches up, (5) a piece that covers the bottom and goes 12 inches up. This will give a solid repair and roughly 8 – 10 mm of glass on the bottom of the keel. Use biaxial /chopped strand fiberglass and epoxy resin. To finish you will need an epoxy filler like Interlux’s interfill 830 lightweight epoxy filler (it is good stuff, I have used it a lot) then sand until fair, and coat with one more coat of epoxy resin. Sand lightly and reapply primer and bottom paint. Charlie G. (#066, Pinguescence).
d. As far as I know, the layup for the keel was poured resin to set the first lead ballast into and then many layers of matt and roving between the 4 layers of lead ballast topped off with a final 14 layers of matt and roving at the turn of the bilge. The keel itself was laid up as an integral part of the hull. If Phoenix has a “shoe” attached to the foot of the keel it was a previous owners modification. Hope this helps. Jeremy P.
e. It looks to me, from the pictures, that someone has cut the fibreglass cover off the bottom to the entire keel. Corbin hulls were laid up as an encapsulated keel which would be filled from the inside. Normally the keel enclosure would be filled with lead although I have also heard of concrete being used at times. It also looks to me as if this keel is filled with concrete. However I could be wrong and misinterpreting the photo. Take a chisel to it and see what comes out. My advice would be to ensure this keel is well dried out and have that fiberglass reinstalled. This needs to be done properly with the right amount of layers which Marius can comment on. Boris, if you don’t have much experience with this I would suggest you engage someone with experience in fireglass repairs. Left unprepared it will certainly lead to serious delimitation of the keel enclosure…especially in freezing winter climates such as Toronto. Jack V (#189, Tangaroa V)
f. The following comments are from a beginner in fiberglass work, although I have made one repair to the bottom of my keel. I was able to enlarge Pic 1 by clicking on it. The sides of the keel, at the top of the pic, looked normal and the forward half of the bottom looked normal, but the aft half of the bottom with the cavities looked awful and your comment about being able to remove walnut size chunks that looked like concrete aggregate causes me to be concerned. Here is a pic that may be helpful, Scaled view of Corbin profile. Sorry that it is sideways. When I click on the view it enlarges. It shows, to scale, where the putty is in the keel and where the lead ballast is. Note that the lead is immediately above the bottom layers of fiberglass. I would follow Marius Corbin’s advice and strengthen that part of the bottom that appears weak and crumbly. Lester H. (#010, Insouciance).
g. Two weeks ago our Corbin was about to be put back in the water after being on the hard for 9 months, during which she had her topsides repainted, when a yard worker noted water dripping from the keel. It transpired that a previous owner had hit the bottom and the repair was to put a fibreglass ‘patch’ over the damage; over the years water had got in behind the patch and up into the keel! The repair involved chipping out the resin until there was no water, leaving a hole about the size of a walking boot. A gallon of acetone was then used to ensure all dampness was removed. Then two gallons of resin, four gallons of thinner and three yards of fibreglass were applied. This took two guys two days lying on their backs with our #173 “Antic” waiting in the slings! Hope this gives you some idea of what has top be done. Regards, Matt E.
h. [Ed, 2019: My understanding is it was ultimately concluded that a previous owner of #131 had sawn approximately half a foot right off the whole length of the keel at some time, to reduce the draught, leaving the bare lead exposed, without making any attempt to seal it back up. It was of course repaired and rebuilt when it was discovered on this change of ownership. DS]
How to go about inspecting a deck for water intrusion damage?
a. Saturation can be determined by a number of methods; a good source for information is Henry Mustin’s book, which if I remember correctly is called “Surveying Fiberglass Boats” or something like that. In this case the first sign was that the deck surface had raised slightly around the cracks in the deck. There were no obvious spots of delamination and soundings of the deck were ok. however when moisture readings were taken it was apparent that water was entering the deck cracks and then, because the deck is slightly curved, the water was moving outboard and the deck was highly saturated at the outboard edges, primarily amidships at the point of maximum beam; this was confirmed by drilling 6 holes from the interior into the wood core in these areas and inspecting the core. Obviously the repair would have been horrendously expensive. All the cracks in the deck were located either above bulkheads or radiating out from the compression post. The opinion of the surveyor was that because the deck has so little form strength (it is a very large flat surface) the deck flexes slightly and that there is insufficient support, causing it to crack around those portions which are supported and cannot flex, IE, the bulkheads and compression post. It was clear from the beginning that these cracks were not simply gelcoat cracks and if the owner had dealt with them immediately, the core would not have been breached and the repair would have been much less costly. Of course that would not deal with the root cause of the cracking, a deck which is not sufficiently supported, but could have been a repair which lasted another 25 years. I hope this information is useful to you and other Corbin owners. Let me know if you have any other questions as I have gathered quite a lot of knowledge about this particular issue. Nick C.
Unfortunately, the coring on parts of my deck needed to be replaced and an additional unfortunate is that I hired the wrong guy to fix it. (See deck repair 1 and deck repair 2 .) Before I knew it he cut the deck up and tossed it and a long list of other incompetence’s. Should have just done it myself from the beginning. I found a product called Flex-Mold and they have a pattern that matches the Corbin diamond non-skid. However, since I don’t have the original section anymore and no good pictures, I’m unsure of the original non-skid patterns in the area. Could you please ask the group and see if anyone would be willing to send me some good pictures of my repair areas? Thanks, Tom Knight, #157, Fabled Past, [Ed. Note: The need for deck repairs usually results from improper sealing of any holes cut through the deck. Be sure to epoxy the exposed layers of the deck.]
a. Tom, No replies, yet, although Marius Corbin did send an email to the man near Montreal who supervised the building of the Corbins. Everyone else is busy sailing. If you have located a company that supplies a rubberized sheet material with a pattern that matches our decks, then you have 90% of the problem solved. Could you send me an email link to that source? Lester Helmus.
b. Understand, I should be sailing also vs doing all these projects 😉 The product is called Gibco Flex-Mold and it’s available from http://spectrumcolor.com/catalog.htm . The part number of the Corbin pattern is GFD302. I called them and they sent me a free sample of about 60 different patterns they have. Tom
Two of our club members are planning to dry out their Corbins and then do bottom work, including epoxy barrier coatings. I may be a third member to do the same. 1. How much credence do you place in moisture readings? 2. What make and model of meter do you use? [Ed. Note: All fiberglass boats are subject to sea water absorption]. Lester Helmus (s/v #010, Insouciance)
a. I took the hull back to the gelcoat in 2001 and then applied 10 coats of MAS epoxy……Iroquois Marine did the work. Cheers, Jeremy
b. If I remember right, the hulls were laid up with vinyl esther resins.[See A44d below.] This should help prevent osmosis blisters. 5 years ago I stripped my bottom down to the gel coat and did not find any blisters. I did use Interlux 2000 (6 coats) before I put on the anti fouling. As far as I know I never had water intrusion in the hull. Moisture meter did find moisture in the deck however, I had the deck completely stripped and all gel coat removed and the deck completely refinished. Some coring needed to be replaced. This work was needed because of careless placement of a point loaded block mounted behind the mast on a flat portion of the deck stressing the area, letting in water. Plywood is not something that tolerates water intrusion well as it will migrate along the grain. I have noticed that the deck laminate is about 1 1/2 to 2 in. thick with the plywood core. The interesting thing about this deck is that the outside fiberglass laminate is only about 1/4 in. thick where the inside is about 1/2 thick. This means all deck repair if needed is done from the outside, much easier to do. Gene Whitney (s/v #069, JOINT EFFORT)
c. I was around when a number of boats were treated in New Zealand. Every moisture meter can provide a different reading. I saw three meters placed on the same spot and they all came up with a different reading. The trick is to do all the work on a boat with the same meter. the numbers are relative. Most people in NZ and OZ were attempting to get their boats down to about 15 percent. it took them about eight months to get there. #043, Balmacara needs to be treated but I would like to get my numbers down to about 12 percent. Turkey may be the place. It is also important to keep the sun off the glass while it is drying. Richard Bacon (s/v #043, Balmacara) [Lester note: Los Angeles would be the place. Our air is extremely dry, especially in the winter when the temperature is at 70 degrees.]
d. We only used conventional resins, no vinyl esther was used. Osmosis and blisters do not have to do with the type of resin used but with the time spent during laminations to roll the air bubbles out of the laminate. Whereas most builders would pop one hull a day out of their molds, we took 4 to 5 days. Hope this will help. Marius Corbin
This is to keep track of hull info as it accumulates, if it isn’t recorded elsewhere:
a. “While living aboard our Camper Nicholson in Tranni, Italy, a Corbin 39 was towed into the marina by an employee in a workboat going about 7 knots. Yhe owners on the Corbin had a bad engine. The employee threw off the line a few boat lenghts out of the slip. The owners headed into the slip with no hope of stopping before smashing into the solid cement seawall. They hit, while I was watching. The boat cement seawall twisted the 45# CQR anchor up like a pretzel. The Corbin bow came up out of the water as she climbed the seawall then settled back into the Adriatic. Other than a destroyed anchor, the Corbin had a few scratches on her bow down toward the waterline. The was no other damage. If you tried that with one of the newer boats you would have to call in a salvage company. Corbin’d are one tough boat!
Jack KB8RJ” (quote from 01-08-2009, 20:01 by iona350 on cruisersforum)
b. “My friend hurricane Larry had one of these boats. Lived on it in the caribbean and in the keys for many years before I met him. The boat was gorgeous, and he took it through one of the many hurricanes that he was in. Boat apparently washed ashore in the virgin islands and Literally broke a hole through the wall of some sort of government building on land during the storm surge.
The story goes that he and the girl he was dating crawled out of the boat and into the building and rode it out between a few large bookcases that had fallen on each other. Apparently the boat was barely hurt, but the building had a bit of trouble. He said that after the storm he only had one drawer of dry clothes in the world, and when he came back to salvage his boat a bit after the storm someone (the people who looted his boat) had opened up his sealed emergency bag and peed on them. First a hurricane and then somone pees on your stuff! Bummer.
Anyway, I digress. This is ancedotal evidence of course, but this was probably the smartest cruisers I have ever met, and if he owned one they must be pretty good. Good old uncle larry. I miss that guy. He knew absolutely everything about everything but wasn’t a know it all, and would only tell you if you asked him.” (quote from 31-08-2007, 03:09 by brian_and_clare on cruisersforum)
c. Photos of hull core plugs taken from various Corbin 39s are below.
d. Airex data sheet and product list are below:
e. There was a Corbin that fell off a truck in 1980 that illustrates the hull strength. Chris Reynolds saw it in 1980, and in his own words, “I saw the Corbin that survived the transport accident in 1980. Muarius Corbin was having a display boat trucked from Montreal to Toronto for the winter boat show in January. There was an accident on the road, and the boat ended up skidding on its side down the highway. Apparently a small car even slammed into it. They got the boat righted and onto another truck, and made it to the show. Corbin made a frame of duct tape around the damaged area of the hull to show how minimal the damage was (basically some gelcoat scratches, no structural damage).”
I have a question with regards to my new Corbin 39, #042, Blondie Too. It was fairly badly scratched up topsides with Hurricane Katrina. I bought her and had her trucked to my home in Peterborough (ie. from warm to temperate climate). I recently had a friend who was a marine surveyor moisture metre it for me and the results were quite discouraging…it seemed to have high levels of moisture everywhere below the water line and on the deck. I wonder if anyone has had any experience with stripping off the hull gelcoat and recoating it and if so where in Ontario it was done and at what expense. The boat sat in salt water most of its life (it is a 1981) and the surveyor seemed to indicate that the work required wouldn’t be worth the cost in the end and that I should think about scrapping the boat and selling off the new engine, rig etc. I, of course, was discouraged by this and am wondering if anyone has had similar experiences with their vessel. I assume the hull has no wood coring, and that the deck has wood coring…if this is incorrect, I would like to be aware of it as well. Tks. kindly. Best wishes to all in the upcoming holiday season. Bill Swales, (s/v #042, Blondie Too)
a. Bill, Sorry to hear about your experience. Our boat is from 1980 and we are original owners. The hull is cored with 3/4″ Airex (PVC) foam down to about the waterline. Is it possible that this has fooled the moisture meter? The deck is cored with 1/2″ exterior grade plywood. We treated the hull with barrier coating, Interprotect 2000/2001, before launching as a precaution. One way to check for excessive moisture is to drill out a core from the inside skin at the bottom of the Airex zone. Don’t penetrate the outer skin! If you then dig out the Airex you will see if there is visible moisture. I have found that the Airex is well bonded everywhere we have drilled out cores for thru hulls etc. Regards, David Salter (s/v #050, Opportunity) [Ed. Note: Marius Corbin says, ” The hull is cored with Airex down to the turn of the bilge, well below the waterline. Airex is the only core that can be used below the waterline, because it is the only core that is 100 waterproof.”] [Lester, I am sure Marius is right. Our boat is too snowbound at the moment to check but I do recall the double inner skin being fairly well down where I can see it easily, in the aft area. In the attached photo you can see the antiskid tape on the double inner skin stretching down well below the rudder stuffing box base. The latter is slightly below the waterline. David Salter.]
b. Dear Bill: I have worked in boatyards for years, and have owned my Corbin since 1995. My experience is that you shouldn’t worry about the moisture level!!!Surveyors and other boat “professionals” tend to rely on these high-tech gadgets and feel they are the be-all, end-all! If you hang in there and enjoy sailing your new boat, you will soon find that although your boat has been in the water most of its life, you can’t kill a Corbin!!! Marius Corbin, the designer, told me that the reason he went out of business, ultimately, was because he built the boat so tough and strong, it cost more than he could charge. There is NO tougher blue water cruiser, and it is the best suited to cruising, as you’ll find if you research the cruising magazines, who have all voted it the best blue water cruiser over the years, and still do even now! Although your boat probably has blisters under the waterline, as mine did when I first bought her, if you work bit by bit on fixing the problem areas every time you haul out, I think you’ll find, as I did, that eventually you won’t have blister problems anymore (I haven’t seen a blister for three years or more). The hull has a foam core, so there is no problem with wood rotting. The deck, on the other hand, has a plywood core, so you may have some rotting there. However, you’ll probably find that the fibreglass on only one side of the potentially rotten plywood core is probably more than sufficient. I recently cut part of my deck out to add a mini-pilot house, and in the 12-foot cut I went through about 10 saws-all blades, designed to go through nails and concrete. You may have some blisters on the bottom, and you may have some rotten core on the deck, my advice to you is to fix her up so she’ll sail safely, and take her out and enjoy her! As long as the rigging is sound (and the chainplates are attached to solid fibreglass, so no rot there), she will go anywhere! A common problem I’ve watched new boat-owners get into is the addiction to making their boat perfect. I, too, was in this trap, and I found, as did others, that I spent so much money on the boat, I didn’t have any money left to go cruising! Then I met a fellow Corbin owner in Guatemala, who was cruising in an unfinished hull, with his possessions stored in milk crates. I was appalled, until he explained that he bought the boat to SAIL, and he’ll finish it as he goes. I changed my attitude then, too! I have sailed my boat from Ft. Lauderdale throughout the Caribbean and Central America, then on through the South Pacific to New Zealand, back to Fiji, and she now sits in Australia. I did all this in a previously neglected Corbin that was covered with blisters and had a lot of deck rot around the anchor lockers. The total refit started in Mexico in 2000 is still underway, and probably always will be, but she’s a solid, safe vessel that will (and has) gone anywhere. She’s the same boat you have, as are all the other Corbins I’ve met around the world, in various stages of repair. In closing, I don’t ever remember hearing of a boat sinking because of a blister! Repair the necessities and go sailing! Marianne Gardner, (#001, Dolphin Spirit), hull #1 [Ed. Note: Dolphin Spirit was recently sold, Jan. 2010, and sailed from the Barrier Reef to Tasmania, 1500 nm. ]
c. Bill, before we bought our Corbin in 2003, it was abandoned for 11 years, we also metered our boat and found the moisture level was quite high. There were 5 other Corbins in the yard when we surveyed our boat. We moisture metered each and every one of them thoroughly. The hulls all measured quite high on the scale and we were somewhat discouraged. We then tested the hull by lifting each end with the stands, it did not flex anywhere. We then took a core sample and attempted to separate the foam from the glass…good luck with that. It’s tough and will totally ruin the foam before the bond lets go. The boat needed a lot of work, so when we brought it home and needed to do some fairing under the keel, we again lifted the boat with the stands, again no flexure. We would tip the boat forward and aft, lifting the ends of the keel to get to work under them without any problems or flexure. We sealed under the waterline with Interprotect 2000 and are happy with that. That was 3 years ago, we have since crossed the Atlantic and are now in France. Happy to be “out there”. Now my point is this, there could be a meter problem. Different cores give different readings. I don’t know enough about meters to make any more comment than that. But if I were to meter a boat and find it was pure water, but was as strong as steel, and it’s siblings metered the same, I wouldn’t worry too much. The center deck however, was quite wet and we replaced it ourselves. If it doesn’t flex when you jump on it, leave it alone. Have someone stand inside the boat while you bounce on the deck. No flex, no problem! The hull is foam core while the deck is plywood core. Replace the deck core with a proper core material of your choice and sail on. If you’re still thinking of selling your Corbin, write me a note, we may be interested when we get home. Happy Sailing. Paul and Christine Melanson on #058, Quintana. Hull 58, in La Rochelle, France.
d. My Corbin is a 1981. Hull number 101. One surveyor in Ontario, tried to tell me my hull was high in moisture……a second surveyor here in Beaufort NC seems to think it is fine……. I suggest average readings are the thing to go by…and remember the meter will always read high near any metal fittings…..such as the webbing in the rudder…which the first surveyor tried to tell me was highly elevated moisture!!!! #101, Two Pelicans is departing Beaufort NC in 3 weeks time for the Bahamas. Cheers, Jeremy
e. Oh boy, I have to say at first, that I would get another opinion. The deck may indeed have some moisture in it if it has been improperly exposed by drilling holes in it without protecting it from water migration. The deck is cored with plywood, but if it is wet, it can be repaired from the top surface as the top is about ¼ inch frp with ½ plywood core and then the bottom is one half inch in glass. The hull below the waterline is solid glass and above the waterline it is cored with airex foam. If you do not have blisters, I would let the hull dry out over the winter and then strip-off the bottom paint and then apply 5-6 coats of interlux 2001. If there are blisters they may have to be removed depending on how bad they are. Gelcoat stripping can be done, and I would talk to the folks at Bridgeport marina in Sarnia, Ontario to submit a quote; they have done this before. I would not be too discouraged over this, as of now. One of the problems with the Corbin is the gelcoat is too thick. The cracking you may see is from the gelcoat shrinking and it will crack all the way down to the laminate and then go even deeper into the laminate. The good thing is the boat is very heavily built and it has tremendous strength and can be repaired. Good luck on this! Gene Whitney
f. This is my answer to Bill Swales, the lucky owner of a Corbin39. My experience with hull moisture was that in many cases the moisture was in the antifouling paint, not in the core. A second test done after sanding some paint gave much better results. If the boat had been out of the water for a long period of time before the test, it may not be the case. The hull is built with an Airex core fiberglass. Very few boats have that core which is made of pure vinyl, is closed cell and waterproof. Because it is made in a mold, the core was cut in small squares and there is a minute distance between the squares that could form a crack or a bad thruhull, accumulate small amount of water that could trigger a dampness meter. That humidity has no effect on the integity of the hull and I would not worry about it at all. Personally I would not even bother with the epoxy coating. Just do the antifouling paint, put it in the water and enjoy your boat. The core that I mentioned above, Airex together with the thickness of the laminate, is what makes this boat hull so strong. I mean by that, exceptionally strong. For example, a Corbin39 spent 23 days on a coral reef and when it was pulled out, thru the reef (1,000 feet), it had a very small leak that the bilge pump could handle. Three of the engine mounts had broken on account of continuous pounding against the coral reef. Another Corbin39 was hit by a freighter going 14 knots and got stuck on the bulbous bow. It took 20 minutes before the cargo ship slowed down to 5 or 6 knots, so that the sailboat could free itself. The two boats travelled sideways for 20 minutes. Despite this, plus the impact when it was hit, the Corbin39 suffered no structural damage and no leaks. Don’t worry about what the surveyor says. He knows nothing about Corbin 39 sailboats and congratulations on owning one; you can now safely take your family around the world if you want. Marius Corbin
g. Bill, congratulations on your purchase of the Corbin. I purchased my 1982 model in 2002 and at that time it had absolutely no moisture barrier on it. It had been launched each year with simply a coat of wax under the waterline (Lake Ontario). After 20 years the gel coat was pristine. Before I launched it for the first time, I put 6 coats of Interprotect 2000 on it (8 at the waterline). After sailing it one year I decided to haul it and upgrade the systems and the interior. I spent 3 years straight working on this and have learned quite a bit about the Corbins. As mentioned by other owners the hull is indeed a sandwich panel with Airex inside. However, contrary to the advice of some, this Airex core does extend a few feet below the water line. In fact during the retrofit I had to abandon a former thru-hull fitting, and rather than leave it in, I removed it and that was when I learned that the former owner had placed the fitting within the cored area. Upon investigating further, the main water intake fitting was also placed within the cored area. The boat had only these two fittings under the waterline as the former owner was very cautious and limited the thru-hulls to absolute minimum (grey water discharges from a holding tank above the waterline). I took this #050, Opportunity to remove the main thruhull and since I could not practically relocate it I created a solid block of resin by using a 6″ hole saw to cut through the inner fiberglass, removing the Airex core within that 6″ area and pouring in solid resin & mat. I redrilled the main water thruhull and patched the Interprotect. When I was doing this work I discovered a small amount of standing water at the thruhull I was abandoning. The main water intake fitting was completely dry. This concerned me at the time; however despite the standing water the Airex core was not delaminated and was indeed extremely difficult to separate from either layer of fiberglass. I noticed that the core material was in fact cut into small squares as Marius had mentioned which allowed for the water to migrate vertically. My thruhull was only about 5″ from the bottom of the Airex core so I drilled out some 3/16″ holes through the interior layer of fiberglass and let it drain. I left them open for the balance of the year and simply filled them again later with epoxy resin. In total I spent 3 years out of the water after which I had it surveyed for insurance purposes and the surveyor did moisture readings on the hull and deck. Not surprising he found the hull to be well dry and found a few local spots at some deck fittings to be slightly higher. For these deck areas I have drilled from the underside and am leaving them open while I determine if my resealing the deck fittings has elevated the source of the intrusion. From my experience I would tend to believe the advice from the other Corbin owners. I would further recommend you find the lower edge of the Airex core and drill some pilot holes to drain any possible standing water…particularly before the hull freezes. Next year I would remove each thruhull below the waterline and either ensure it is placed in an area of solid laminate or create a solid laminate area and reseat them. This will give you a visual of what is going on down there and peace of mind. Hope this helps & don’t hesitate to contact me if you have any further questions. Jack Verheyden (Hull #127, Kathrian, a “Special Edition”)
h. I recommend that any fiberglass boat intended for use in the tropics be given barrier protection with epoxy. I had a Bristol 29 that had no blister problem for 15 years while in the cool waters of New Jersey. After one year in the Caribbean the entire bottom became full with quarter sized blisters! Lester
i. Re: the deck moisture / delamination: We had high moisture levels at areas where the deck sealant had failed [after drilling holes]. In those areas, holes in the deck core were not sealed at their edges with [epoxy] resin, so if the sealant failed moisture could get into the mahogany deck core. I think moisture meters are good tools but tricky to use. We bought a moisture meter, the same one our surveyor had, so we could monitor the moisture in the deck. Some areas, where he [had] indicated there was high moisture, after we removed that portion of the deck we discovered the mahogany to be dry. We had delamination [in] one of the hatches; it was an easy fix and nothing to worry about. Hope that helps, Stephen Lefneski (s/v #187, Tobaggan)
I need advice regarding cracks on deck and how best to repair them. I fear water has soaked into the encased wood – plywood. I hope it will dry out while in Tunisia during the coming months. I have opened these cracks, which range from hair lines to almost 1/32″ in width, and have sealed the worst of them temporarily using silicone. This should help the drying process and allow for a more permanent repair. I would appreciate help. Thank you very much. Peter Voges (s/v #099, Escapade)
a. Hi Peter, My name is Bob Cox. I have owned Dorisea, (Hull #070) for 12 years. I think I have finally succeeded where others have failed, to fix the thousands of ugly gelcoat cracks in the deck that, although cosmetic, de-valued the boat. None of these cracks intruded into the fiber glass, so unless your situation is different from mine, I do not feel you have the threat of water intruding into the plywood core of the deck. The problem stems from the fact that the gelcoat is far too thick. When I bought the boat, the deck had been painted with a very hard non-skid paint. There was also several coats of more paint on top of that, as well as a flexible primer under it. The cracks migrated through all of it. I was convinced that all the paint needed was to be flexible in order to prevent the cracks from re-appearing. One day I was working with some roof paint called Snow Roof. It is a water-base, elastomeric paint. Little bells went off in my head, and a web address on the can led me to their site and a listing of all their products. This included a product called Kote-A-Deck. The site also listed many applications which included Boat Decks. I called the company, and they were very helpful. They explained that the products would not be suitable for application on gelcoat unless the surface was sanded firs with 40 grit paper, to insure adhesion. They then recommended two products. Prime-A-Deck and Kote-A-Deck, both elastomerics. Company contact info. follows: Snow Roof Systems 1499 Enterprise Parkway Twinsburg, OH 44087 Phone: (888)-321-5665 FAX: (888)-296-5665 E-mail: email@example.com Web: http://www.thoroproducts.com
I began the long, hard job of removing all the crap that was already on the deck. That was the worst part and hopefully one that you will not have to do. Then I sanded the deck with a belt sander and 36 grit paper. I sanded the gelcoat until all the original molded non-skid surface was gone. Then I scrubbed the deck with bleach to kill anything living in the millions of cracks. Then I cleaned out all the cracks with a high-pressure-washer. It was now ready to apply the primer.
I began by forcing primer into all the cracks with a squeegee. As the product dried, it shrunk into the cracks, so I did it again until the cracks were filled flush to the deck. Then I brushed on 3 coats of Prime-A-Deck. Then I applied 3 coats of Kote-A-Deck. (The non-skid grit is mixed into the paint at the factory-just stir and apply) My deck now looks beautiful. I have pictures, before & after, if you are interested. The other part of the project was the water-channels and trim parts of the deck. They had many cracks too. Here I used a high-speed drill and tiny router bit to open the cracks down to the glass. I found spots where the gelcoat was 1/4 inch thick. I used Marine Tex to fill the trenches I cut. At first, I attempted to color the Marine Tex to match the color of my boat. I got close, but never satisfied. I resolved myself to the fact that I would have to paint the repaired areas. I had shied away from that idea because West Marine (and others) couldn’t or wouldn’t match the color. This would leave the repaired areas standing in contrast to the rest of the boat. Then another light went off in my mind. These marine supply places don’t make the products they sell. They just triple the price and put them on the shelf. I went to a few places in search of a single part polyurethane paint tough enough to walk on. At a True Value hardware store I found a product from “General Paint & Manufacturing Company”. It’s for interior and exterior floor and trim. I solicited the help of their paint man. He said if I can bring him a piece of the boat, he can scan it and match the color exactly. That’s what I did and that’s what he did. The paint went on beautifully with a brush (which they gave me as a thank you for doing business with them) and now looks like it was sprayed on. Just like BrightSide, except I got a perfect color match and $24 per gallon instead of $30 per quart. By the way, if you’re a “Cetol” man for your topside teak, Sikens sells through their dealers a product called Natural 078. Same stuff as Cetol Marine with one exception. Cetol Marine is $30 per quart. Natural 078 is $30 per gallon. I’ve had it on my wood for 5 years. Not as beautiful as varnish, but a fraction of the work to keep it looking pretty darn good.] Well Peter, that’s what I did with the deck of my Corbin. I’m extremely pleased with the result. I just recently completed it, although I did a few test places 5 months ago. I’ve had no problems in those areas. Time will tell, and at the very worst, it’s real easy to repair. Just slop on a little paint. Actually one slight problem has emerged. It didn’t use to bother me so much when it got dirty and the birds crapped on it. It looked lousy anyway. Now I find myself washing the deck every few days. Gotta keep it looking pretty. I wonder if those Marine Stores sell a bird repellent? Best from Bob Cox (s/v #070, Dorisea)
a. The hull inside was painted with a Canadian two part epoxy called Endura but I am sure any epoxy paint would do. The worst job is the preparation, to grind the hull to get rid of the waxy coating on top of the fibreglass, if it is in the condition where it came from the molding. The paint won’t stay long on the waxed fibreglass. It is possible to use sanding disks or a belt sander (coarse, 24 grit to minimize plugging up) if you can get access. I suggest that this is a good job to get someone else to do, ensuring that they take care not to damage anything. In some areas we put regular alkyd paint on top of the epoxy paint although it can take a while to dry machineryspacerudder.jpg. David Salter (s/v #050, Opportunity)
What should I do about those cracks in my gelcoat? Jeremy Parrett (#101, Pelican 1 / Two Pelicans)
a. Gelcoat cracks Deck or Hull ???? Since the Corbin is not prone to flexing, the gelcoat cracks are purely cosmetic and largely due to excessive amount of the gelcoat material. Case in point. We have had our boat Awlgriped and Epoxied recently and when the issue of the gelcoat crack repair came up, our shop elected to NOT to fill the cracks but to sand the hull and seal with Interprotect Epoxy several coats. This stuff has the ability to surface stretch and flex 40%. Our repair shop is: R Moreau Marine Refinishing here in Penetang, Ontario. Rick has been in business MANY years and has a very excellent reputation for workmanship and fair pricing. ( having done several Corbins in the past ) He is a local legend and his work from 20 + years ago still looks as new. Just sharing our experience.. Regards, Frank Bryant (s/v #186, Visitant)
b. Thanks for putting my mind at ease. When I bought Hull 101 last year we sanded the underbody and applied 10 coats of Maas epoxy so I shall now only have to deal with the deck and topsides in time. I am more than pleased with my Corbin. I had ordered one in 1982 but cancelled for reasons you may guess!! Jeremy Parrett (#101, Pelican 1 / Two Pelicans)
What should I do about those cracks in my gelcoat? Jeremy Parrett (#101, Pelican 1 / Two Pelicans)
The question was posed regarding the layout of #189, Tangaroa V. The full set of responses is included here firstly because of the very clear and evidence-based response at the end from Marius Corbin that is both a ‘yes, it is OK’, and gives insight into the structural design of the Corbin 39. Secondly it is interesting to compare that with some of the other responses, and to reflect on that when reading through and assessing the validity of some other opinions expressed elsewhere on other subjects.
a. Nice woodworking but a bit scary on the structural engineering, I’d say. Jack
b. Hi, we agree that these photos indicate a lack of deck support. Looks beautiful but waves on windows could be extra dangerous for this boat. Rod Kerry (#092, Vision Quest)
c. Are you saying that without more rigidity the hull might flex, allowing the windows to pop out? Maybe the pilothouse windows also? Skippers, A few days ago I sent you an email regarding a Corbin that was built without the main bulkhead under the pilothouse windows. I was concerned about structural integrity. Thus far, I have received only three responses. I feel it is incumbent upon us as the Corbin 39 Owners’ Group to comment on this departure from the original design plans. Is the present owner in danger of a serious accident? What about the person who buys this boat some time in the future? Please send your replies directly to me and I will post all of them on our Q and A page. I would like to hear from Marius Corbin and Collin Harty, especially. Lester
d. I find the photos of the open plan Corbin rather intriguing. The layout has definite similarities to the Nonsuch 30….also the Niagara 35 Encore Edition. …Jeremy
e. I would think the structural integrity of the deck would depend on where this person placed all the bulkheads. The cabin roof would sit on this particular bulkhead and I have not personally seen another Corbin where this main bulkhead was not there. I would be interested in hearing what Marius Corbin has to say since this was his design. Thanks, Christine Lawton.
f. While the boat may look very nice on the inside (as well as outside), there is no way i would ever raise a sail. The apparent absence of the structural bulkhead between the pilothouse and main saloon is a serious issue. i would suspect that stress transferred from the rigging (even just at dock or anchor with wakes and wind loads) will cause the deck to flex because of the missing bulkhead. Doug Archibald (s/v #158, Chaos !!) [The upper and intermediate chain plates are opposite the mast which is located at the aft head bulkhead. Therefore, the deck should not flex. Lester]
g. I’m surprised at the lack of comments / responses as there are many very knowledgeable owners here. Not being a naval architect or structurally inclined for that matter, I elected to decline a formal comment, but having had another look at the pics., I did not see the mast support ??? or is it keel stepped ?? anyway, without the bulkhead under the P.H., I would be reluctant to go ” off shore ” but for coastal cruising…..??.. I’m not qualified to comment. It looks like a very nice boat otherwise, Frank Bryant (s/v #186, Visitant) [Tangaroa has a substantial compression post under the mast which goes down to the hull. Lester]
h. Thanks for including me in this email and for posting #189, Tangaroa’s photos on your Corbin site. As our harbour-master, I appreciate your questioning and validating of this very uncommon Corbin design. This boat was designed and built in the second half of 1988 in Corbin’s yard and was also completely equipped in their yard including auto pilot, generator, air conditioning, etc. It had in mast furling, electric windlass,.etc. I have all the original drawings and documentation from Corbin including some comments by Mr. M. Corbin to the attention of the original owner. The interior was designed for a couple to live aboard in complete comfort with a very large living area and only one closed cabin, (forward) . Two heads are installed, one amidship on the port side and the other aft also on the port side . The whole volume under the cockpit is the engine room where the generator with its own diesel tank, water maker, main engine, (Perkins 60 HP), water pump are installed. Access to all those equipment is very good through cockpit deck that becomes a large hatch.The first owners took Tangaroa V down the Pacific Islands for a year or so and came back to Canada afterward. My intentions are to make Tangaroa V and its crew of two seaworthy for bluewater cruising. We expect to retire in about three year and start cruising wherever the winds take us. Best regards, Guy Viger (#189, Tangaroa V)
i. I have considerable boating experience but no professional qualifications. From the photos…I see a pair of semi bulkheads each side under the sill at the leading edge of the pilothouse where it joins the deck. These I assume are installed to the hull and below the floors as Corbin would have done. As the Corbin is cored and overbuilt this should be adequate support in this area, although I would add a couple of nicely finished posts from floor to deck head each side of the ladder joined to a shallow cross beam. The C & C’s of old used a system like that to open up the interior. I am concerned that the large area of the deck above the main cabin has no semi bulkheads or beams. I feel that in time this might lead to some deck flexing. The mast loads are carried to the keel by a compression post which is not visible The bulkhead (in the photo) in that area looks substantial. The cabinet work and upholstery are beautifully finished. The sofas and cabinets opposite are probably integrally glassed to the hull providing adequate support. Without more detail, especially measurements from the sill /leading edge of the pilothouse to the mast area support/bulkhead/compression post it is difficult to guess how much deck is unsupported. It appears that the main cabin forward bulkhead has been moved aft, locating it in the area of the mast? I believe I read in the original builders ads that one of these boats had been rigged and sailed with no interior at all except for a compression post ! It will be interesting to hear what the professionals have to say ! I am reminded of my Navy days sailing a 40 foot open wood gaff rigged cutter with just thwarts for side compression loads and stringers to prevent hogging and sagging. If all the cabinet work in Tangaroa is well glassed in to support the hull shape, then the deck just becomes a cover to keep out the weather. It is substantially constructed….has good camber…..but it does need reasonable support…..how much structural strength the deck adds to the whole boat is open to question ! Anyhow that’s my ten cents worth…and TangaroaV is one of the nicest Corbins I have seen ! Regards, Jeremy
j. The photos show a very nicely finished boat, both exterior and interior. As you note, the layout is very unusual. The instructions I received from Marius Corbin regarding the bulkheads was that there were 6 structural bulkheads and that they should be located not greater than + or – one foot from where the Dufour design showed them. I would think that the absence of a bulkhead where the front of the wheelhouse meets the deck cutout would result in a significant weakness. In Photo1 I can’t see any reinforcing such as a deck beam and there is no vertical pillar either. Regards, David Salter
k. I’ll have to fall back onto the sage wisdom of the anonymous broker who said “Corbins are like a box of chocolates, you never know what you’re going to get until you bite into one.” [This is true of every boat. Lester] It is simply impossible to say whether the interior layout of Tangaroa V has compromised her structural integrity by looking at the photos posted. It would take a much closer inspection of the boat to know. With structural PVC foams, knitted glass and/or carbon fibre, epoxy resins and substantially engineered structural knees, the technology exists to stiffen the hell out of a design like this. I would also note from the photos you posted that there seems to be a major bulkhead inline with the mast and major rigging loads. You would have to know more about the specifications of the sail plan, pull the headliner, delve deep into the lockers, and talk directly to the builder about his laminate schedules to know it this boat was engineered to take the necessary loads. There are a number of very high-end raised saloon and pilothouse boats on the market today that have opted for this very same open layout. It is possible to do, put impossible to know if it was done right solely by looking at these photos. Best regards, Collin Harty
l. Guy, Does Tangaroa have a compression post to the floor (not the sole) which supports the mast? (Answer: Yes, a 6″ diameter steel post) If yes, is there a bulkhead from the post to the hull, which braces this post? (Answer: Yes) Lester
m. As I mentioned to you, Tangaroa V has been cruised extensively in the South Pacific during more than one year. She is now almost 17 years old. There are no stress indication, (cracking, ….etc), anywhere on deck or below desk. I have attached more photographs that show the structural bulkheads on both the port and starboard side. As you can see they do not cover the whole area and thus allow the open view concept. This design conveys a tremendous feeling of space and volume that I have only seen in much bigger boats and is a great invitation to live aboard for extended periods of time. See Tangaroa Pics, Guy Viger.
n. Regarding the present layout, perhaps a structural header that spans from stbd to port hull ribs can carry the loads anticipated on an ocean crossing? I think it would be super if Marius Corbin could weigh-in on any kind of reductions in the bulkheads. [See A48n, below] I’m not speaking about total removal, but opening up the wall area on the port side just beyond the galley or the settee for example. Thank you kindly on your efforts in establishing the website. Tim O’Neil (#138, Whaleback- homeport Boston)
o. The Corbin was designed to be an ocean-going vessel. The plan provided for numerous bulkheads to give the boat the interior support for strength. This vessel looks to be missing 3 bulkheads that our boat has in the salon and pilothouse. I believe that this compromises the structure and could lead to possible problems such as hull flexing such as you describe. The deck is not getting the proper support and I cannot see a mast compression post in the salon. [It is in the aft inboard corner of the head compartment bulkhead. Lester] I personally would find this dangerous. Rod
p. Tangaroa, was one of the last layouts I designed and was factory built. Not to worry about the integrity of the design as far as strength is concerned. All the bulkheads are there and the boat is plenty strong. You seemed concerned about the one at the pilothouse. It is there, like all our bulkheads, laminated on both sides in the hull and in the deck. The part that seems to be missing, is the dash that unites the bulkhead to the windshield of the pilothouse. That part has never been structural and the bulkhead never went as high as the overhead of the pilothouse. That boat [Tangaroa V] is a 39′ like all the others. Tangaroa felt a lot bigger inside than the others, because of the openness of the design and two of that version [Demontigny] were built. I must confess that this is the layout I prefer for myself, maybe because it is the latest of all the layouts. Have a great day. Marius Corbin
q. Guy, 1. I know what the bolt heads are; they are rivet-like fasteners holding the pilothouse down onto the deck. On my Corbin, bolts were used and the nuts on the inside are covered by 1/2″ foam and 1/16″ vinyl sheeting. Also, your pilothouse appears to have a lid which is riveted on. It appears a separate mold was made in order to accommodate the two large hatches and the dorade holes in the roof. 2. The longest unsupported span, fore and aft, is 7′ on my Corbin. On most Corbins, it is about 10′. But on your boat, it is about 16′, from the companionway to the mast compression post. I think this is too long and a potential hazard in a heavy sea with a knockdown. 3. If I were you, before taking off around the world, I would consult a competent naval architect to look into this question. I recommend John Letcher, a PhD from Cal Tech, experienced singlehander, author of the first comprehensive study of self-steering techniques, designer of sailboats, and now a designer of boats and ships using computer techniques. He is located in Boothbay, Maine. 4. In order to be a bluewater boat, I think that TangaroaV needs a substantial beam athwartship where the forward end of the pilothouse sits on the deck. A SS truss about 6″ high would do the job and would fit into the open appearance of the interior. This beam could be tied to the existing wooden knees outboard and supported by two posts (lattice truss or poles) resting on the inboard ends of the two existing partial bulkheads, one in front of the helm and one between the back-to-back settees. That’s my two cents worth. Lester Helmus
r. Guy, Here are some further thoughts on this question One is redeeming, the other is less so. 1. In the severest of wind and sea conditions, Tangaroa should remain intact; the worst that might happen is loosened windshields, delaminated plywood, and/or delaminated fiberglass, all due to flexing of the unsupported main deck in the area of the windshields. Therefore, I conclude the Tangaroa open layout design is structurally safe. 2. When you go to stock up on victuals for that round-the-world cruise you are going to wish for the storage shelves and drawers that the main dashboard/bulkhead can provide. My #010, Insouciance has an additional bulkhead with shelves, drawers, and icebox-turned-storage box which is at the forward edge of the galley. This bulkhead plus a post lend added support to the deck which is needed for a keel-stepped mast. Good luck, Lester.
s. Our Corbin 39 hull #144, “Cormorant” was built by Don Ney in consultation with Marius Corbin. There is no bulkhead under the pilot house windows as in the factory models. This boat has been around the world one and half times and is still structurally sound. The inside steering station is mounted on a shoulder- high console (same level as deck) and is about 2.5 feet aft of the base of the forward pilot house windows (sort of a cathedral ceiling for the galley and main salon which really opens up the living space.) Don Ney told me that Marius Corbin toured the boat after he (Don) finished it and said “Why didn’t I think of that!” All the best, Harry and Jane Hungate, cruising in New Zealand in #144, Cormorant.
I am cruising in Cuban waters at this moment and I will be cruising till the end of April, then be on land for the rest of the year. On another note, after a very nasty overnight of sailing (30 knt on the beam, sea 10 ft) off the Cuban coast, I noticed that I had water seeping through the joint hull to deck. Is it a common problem of the aging Corbin or is it a rare occurrence? I already re-caulked all the fasteners at the joint. What is the fix for this problem? Valois Nadeau, (#096, Giva).
a. Wow, that is a first. I thought the hull to deck joint was done at the factory……..maybe Marius has some comments. My bet would be the chain plates deck seal are leaking. I have had to dig all mine out and using 5200 I refilled the recess and reinstalled the cover plates…..no more leaks !! Jeremy P. (#101, Two Pelicans).
b. My preferred fix is to take off the toe rail, sand/grind the joint surface beneath and then run a 2 or 3 inch strip of fiberglass over the joint. Fill the surface, fair it and then paint. You will then have to re install the toe rail. Although you will still have the holes created by the bolts that hold the toe rail down, you will have eliminated the vast number of hull/deck thru bolts as sources for water leakage. If you don’t have the time to lift off the whole toe rail, be sure to fully renew the caulking around the edge of the toe rail at the point where it meets the hull/deck. Use a quality caulk with a good UV resistance. I’m sure West Marine, Cuba (!!) will be able to advise. All the best, Charlie G. (#066, Pinguescence).
c. Valois, (1) Here is what John Neal said Solving Caprail Leaks “Hull to Deck Joint: There are several methods of attaching the hull and deck of fiberglass boats. The most common method utilizes bolts or screws protruding through on the inside of the hull to the deck joint. This a mechanical clamp joint is relying on the bond of a sealant adhesive (3M 5200 is often used) to stop leaks. After eight to 12 years and several thousand miles of ocean sailing the sealant/adhesive loses some of its elasticity. Due to the working of the boat and the different climatic conditions the toerail and hull expand, contract and flex at different rates eventually weakening the bond, allowing water to follow the bolt or screw threads down, and drip on the inside of your lockers. Two methods of solving caprail leaks. Remove the teak cap rail or aluminum extruded toerail and clean and re-bed each bolt. Radius the inside of the joint with epoxy and microballoons and then lay several layers of fiberglass tape over the inside of the joint, totally sealing it and strengthening the area at the same time. A more trouble-free hull to deck joint utilizes substantial fiberglass bonding on the interior of the joint, eliminating mechanical fasteners and leaks. (2) I say that leaks are caused by: (a) adding thru-deck fasteners improperly, (b) pushing the boat by the upper part of a stanchion instead of its base, and (c) etc.
I’m going to be looking at an older Corbin 39 that has soft spots in the cabin sole. I’d like to know how the boat was built to determine how serious the damage is. Could you please tell me, if in your opinion, if soft spots in the cabin sole are structural problems related to rotted thwarts (knees) or a cosmetic problem? I was “told” the boat was a factory boat, but the owner is dead and his widow may not really know. If the boat has structural problems I probably won’t buy it, if all I have to do is replace some flooring, I’ll try to buy it. Thanks & Sincerely, Tom Hally.
a. I don’t know how the factory-built boats dealt with the cabin sole. In my boat the supports, or floors, are like vertical mini bulkheads made from 2 layers of 3/4″ mahogany ply that were bonded [together] with epoxy and then covered with fibreglass. Then a piece of solid mahogany, about 3″x3″, was attached to the top to span the hull. I made most of my cabin sole consist of removeable panels so that the bilge and hull could be inspected. This is particularly important in the event of external hull damage. If you are keen on buying the boat I suggest you ask the owner if you can cut out a section of the sole. This is fairly drastic but I can’t think of another way to resolve the question. You should be able to advise the owner that other potential customers will have similar concerns. The cutout panel should obviously be in a position that would allow it to be used as a future keel access hatch [and for storage]. Regards, David Salter (#050, Opportunity).
b. Don’t know what to make of this ! Certainly it’s nothing structural, just an underfloor issue. maybe ?? the plywood got soft somehow … ? or maybe it was too thin in the first place ? My sole is on 3/4 plywood. Sorry I could not contribute much. Cheers, Frank B. (#186, Visitant).
c. Recommend that he take a look below the floor boards to see if there is an obvious reason for the soft spots. If he is still interested in the boat after that then a surveyor can help him determine whether this is a big or little issue. Stephen L. (#187, Toboggan).
d. Our 1984 Corbin #153 also has soft spots and one place where you can see the sole was replaced. Getting a closer look, it seems to just be some sole lamination deterioration and not structural (a future project I’m sure). In one spot it looks like some penetrating epoxy was used with limited success and some discoloration. Gene & Patti S., (#158, Swell Dish).
e. Many people say their boat is factory built but it is not always the case. The flooring is built with 3/4″ mahogany plywood, covered with 1/4″ teak and holly floor. It could be that one of these two parts has separated or is rotten. I would doubt very much it is structural. There are openings in the floor that will allow you to check for rot from under the floor. Have a wonderful day. Marius Corbin.
f. It’s going to be difficult to tell what the issue is and how extensive it is without taking a good look. Then there’s the question of differences in how each boat was built. When we purchased our Corbin, we had the sole factory-installed. In this case, the knees and stringers below the sole were well encased in fiberglass but the sole itself was just raw marine plywood without any sealant applied to the underside, allowing for the potential for rot. We didn’t have issues during our time owning her, but who knows now. Chris Reynolds, Formerly (#083, Tamalmar).
g. If factory finished, the supporting floors should be of substantially thick solid mahogany beams and thick marine mahogany plywood bulkheads. Because most of the boats were sold in various kit plans it is impossible for me to answer your question. However, if the joinery inside looks professionally done then the boat was probably factory finished. If the boat was kit finished only a careful inspection of the supporting flooring (the supporters of the sole) will tell if the problem is structural or cosmetic. The entire interior of my boat was finished by the previous owner and is still very solid despite the intrusion of fresh water on at least two occasions when the hull up to the salon sole was immersed in fresh water. Your problem is probably cosmetic. Inspect the flooring. Also, smell for rot. Lester H. (#010, Insouciance).
h. Attached are two pictures (I thought that I had more) of my boat under construction at the factory in 1984. The first picture shows the forward bulkhead in the main salon. Looking closely, you will see just aft of the main bulkhead, a stringer glassed to the hull; there will be one glassed to the starboard side also. Salon Sole Support Stringer Fwd There is also a bilge bulkhead glassed into place a few feet behind the main bulkhead. The second picture shows the underlayment plywood (appx 3/4″ marine grade) sole resting on the above-mentioned stringer and bilge bulkheads and glassed into place with tabs on the outboard edges. Salon Sole Plywood The underlayment plywood sole was secured to the bilge bulkheads, I believe, with Morebond and screwed down with SS screws. There would be another bilge bulkhead between the two tanks seen in the picture. All of this created a solid floor, covered with an appx 1/4″ teak and holly plywood which was secured with Morebond. I would suspect that water, perhaps from a leaking tank, may have somehow collected onto the plywood underlayment between the top covering teak and holly and the underlayment. This, over time, would cause punkiness and softness. Just a wild guess. Doug Archibald S/V #158, CHAOS !! (ex) [Ed. Note: The two pictures show a very solid substructure that not only supports the cabin sole but makes the hull more solid and rigid.]
i. I have hull #025 and have been installing new sole for awhile now. Thing is on my Corbin the sole is not structural but can add support to the overall stiffness. I would inspect the soft spots to see if it is in the stringers or supports. More than likely the sole is the issue. I am using an African rosewood that can be submerged in water for long periods without ill affect with only teak oil applied. Even if it were a small amount of rot due to poor sole installation it would not scare me from the purchase. These Corbin’s are literal tanks of the oceans and if water intrusion is caught early and repaired properly the boat has many more oceans to cross…….Fair winds, Keith Boettger (#025, Agape).
Is it possible to install a thru-hull at the bow lockers so seawater can drain overboard without coming into the boat? Charlie Haskell (#066, Pinguescence).
a. Our Corbin came with the bow lockers interconnected via a small hole in the separation nearest the bow and one drain on the port side. Works very well and drilling a through-hull above the waterline would be simple. Best regards. Gerry & Brigitte Stuurop (#087, Octopus I) [Ed. Note: Or simply allow the water to drain from the bow anchor locker into the nearby bilge, from which it will automatically pump overboard.]
b. The bow lockers on my Corbin, Perpetua, drain directly to outside. A little water tends to collect at the bottom, but, for the most part, they stay pretty dry. I believe the drains are just a simple hole, with a stainless steel vent cover located on the outside of the hull. Good luck! Bill Gifford (#078, Perpetua).
c. I imagine most Corbin bow lockers are different if they are owner finished. Mine has a sloping bottom (down towards the bow) where it is above the foot of the forward-cabin berth. The forward end of the locker has an athwartship “bulkhead” resulting in a well each side after the central divide is installed. I have a drain at the bottom of each well, where they exit the hull, about 12″ above the waterline, I have small stainless clamshell vents (see West Marine P/N 180356 type) with the opening facing aft and angled down slightly. See photo Sail Locker Drain. The base of these wells is a continuation of the forward berth. It is more or less “dead” space but I have put some chain there. I took care to make the sail lockers entirely sealed off from the rest of the boat interior. Originally I had some mildew form on the underside of the locker lids so I installed vents there and that cured the problem. It allows any wet ropes, etc. to completely dry out although I generally don’t put anything wet in there. Your rot problem might have been accentuated if the lockers were not ventilated. I presume your central locker divider is where the inner forestay is attached, which is what I have. Where the chainplate is attached I doubled up on the divider. I recall that this wood is 3/4″ ply. Everything is heavily glassed over. I hope this is helpful. Regards, David Salter. ( #050, Opportunity).