FAQ

How do I rewire my mast? Can you please help. I am trying to do some rewiring in the mast (Isomat): radar, coax, and a triplex wire for deck and steaming light. Are there internal conduits in the mast that extend below the side exit? Do I need to pull the mast? Gene Stoddard (#158, Swell Dish). a. All masts are probably different. I have an Isomat clone (Cinkel Canada) and it has 3 extrusions inside the mast, 2 either side near the front and one aft.. They go the full length except that one or two (I forget which) are cut by the upper spreader supports. The extrusions each hold a plastic conduit tube and may be cut at whatever height one desires. I believe the only way to resolve wiring problems is to pull the mast. David Salter (Here’s my mast base, Pic 1) (#050, Opportunity). b. We had an Isomat mast previously on our Corbin. It had two conduits, one fore and one aft. The wires within our conduits were bound together with cable ties every couple of feet or so. These wires flex snakelike back and forth across the conduit taking up much of the conduit space. We needed to take our mast down to get the wires out of the cable wraps and add another wire in the conduit. We disconnected all the wires, slid the entire bundle out, added a wire, attached it with cable wraps, slid the whole bundle back in, and reconnected everything. It was not as difficult as it sounded, and went quite smoothly. Hope that helps, Stephen Lefneski (#187, Toboggan). c. I have an Isomat mast which I rewired several years ago. I had no conduits in the mast initially but Isomat sells various size conduits which can be slid up the mast from below into a retainer slot so they are fixed. In order to rewire your mast properly, and certainly to install additional conduits, the mast must be removed and put on sawhorses. Pull out all the old wiring and even remove the mast head temporarily for ease of pulling. Find the supplier of Isomat masts and accessories and purchase the new conduits you need. The conduits can be trimmed at the exact point where wires need to exit such as at the spreaders for spreader lights or radar domes before continuing on the the mast head. I would suggest signal wires be in separate conduits from the power wiring. If you have room in the conduit you might consider a spare wire for some future device or antenna you might want to install. Be sure to file smooth the holes where the wire exits the mast and that the wires are not pinched when exiting. All new wiring should be in double insulated sheaths and be tinned stranded wire of the proper gauge for the devices run. When the wires exit at the spreaders or at mast head they should exit at 90 degrees and make a slight bend down before heading back up again to the device. This will prevent water from entering the mast. Good luck with your rewiring. Jack Verheyden (#127, Kathrian). d. There is no way you can deal with this mess without pulling the rig. The wires in the conduit will be impossible to pull out or use as pull throughs for new wiring. I rewired Two Pelicans mast down. The reason the wiring exit is higher than the conduit end is to form a drip loop. This exit would be the one to use for all the wiring including the radar if its cable is properly shielded. On deck I would mount an inverted U-shaped stainless steel conduit, one end attached by a flange to the deck where the wiring feeds below, the other end half the length of the U would be where the cables are fed in, then up and over the U and then down. With a suitably sized piece of pipe and a flange welded on the longer end you will have a barrier to sea water going below through the conduit. Plug the pipe after the wires are fed in, either with putty or with a piece of plastic tubing where the wires are fed through, one end inside the mast opening, the other slipped over the inverted shorter end of the conduit. Use the proper sized silvered copper wiring……expensive but a one time fix. Good luck, Jeremy Parrett (#101, Two Pelicans). e. At the time most Corbins were being built, Isomat spars did not have conduits in them. Instead, they had two internal extruded tracks, similar to the sail track on the aft outside of the mast tube. Isomat would take the appropriate lengths of mast wiring, secure miniature slides every 12 – 18 inches along them, then “hoist” the wiring harness in one of the internal tracks, while fishing wires out of the mast tube at appropriate locations. With more complex wiring harnesses, they would split the bundle into two harnesses and use both internal tracks. There is no way to adjust the wiring on a setup like this unless the mast is unstepped. You may have something that’s been retrofitted, including a conduit (you should be able to see fasteners on the outside of the mast tube used to hold the conduit in place). In some cases, where advanced planning was employed, it may be possible to fish new wires through a conduit while the mast is stepped, but it is always easier while the mast is laid flat. In any event, your biggest issue may be the exit plate on your mast; a non-standard fitting for an Isomat spar and one I’ve never seen before. Good luck, Chris Reynolds, former owner of #083, Tamalmar, Corbin 39 pilothouse cutter. f. The rewiring of a mast is much, much easier done with the mast down, especially if you are going to replace all the wiring. That being said, many times the wiring is filled with 3M 5200 at the base of the mast to prevent water from entering. To get wires out of 5200 is not an easy task if you don`t have access to it. There are internal conduits but the radar wire was big and often times did not make it inside the conduits. The radar cable usually goes out at the 1st spreader so it is about 20`long. Again, May I suggest that the mast be taken down for re-wiring. Have a wonderful day. Marius Corbin

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.

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

I go up at the start and finish of each season to install/remove the electronic wind indicator and the Windex so that the crane hook can’t damage them. Our system of lifting the mast uses a 135′ length of rope that is looped under both the lower and upper spreaders and extends above the mast top. Once the mast is hanging from the rope, for the haulout time, one can pull the heel of the mast aft and it gradually comes to the horizontal as the rope slides along the crane hook. Launching is the opposite action. In the photo we have already removed the sails and the boom. David Salter (s/v #050, Opportunity)

Asked by Hans Bavelaar (#072, Tahei)

a. Pros: 1. Increases the area available for the headsail; boat can go faster. 2. Decreases angle the headsail makes with the centerline of the boat. Boat can point better when closehauled. 3. Enables placement of anchor roller forward of prow, but best if rollers are placed at forward end of bowsprit. Moves overall center-of-effort forward, reducing weather helm. Cons: 1.Reduces maneuverability of boat in marinas. 2. Increases LOA, increases marina fees. 3. Is OK when used with a furler, dangerous with hanked-on headsails. 4. Bowsprit tends to move aft under headsail forces.
Lester Helmus (s/v #010, Insouciance)

b. As Lester suggests, the bowsprit tends to go aft, making it difficult to hold headstay tension when the headsail forces increase. It can be bad news when you’re in 35 KTS + winds for many hours. Our bobstay mount was displaced on two occasions while crossing the Pacific. Half inch bolts were bent. We also took a little water on. We think that we have now solved the problem. We welded 8″ x 8″ plates on the sides of the mount. This has allowed us to bolt from the sides. This also gives us the option of attaching our sea anchor to the new mount. Richard Bacon (s/v #043, Balmacara), now in Oz.

My mast has a one piece elastic which is held to the deck collar with a large hose clamp and to the mast with a similar large hose clamp. The elastic deteriorates over the years and develops leaks. I have been caulking these leaks and then spraying with a rubber waterproof liquid. But now I need a better solution to the problem. Spartite is very expensive. Is it worth the expense? Lester Helmus, (s/v #010, Insouciance).

a. Yes there is better solution than Spartite. On my previous boat (ketch rigged) I used on old truck inner tube protected with Sunbrella, matching the sail cover. When I sold the boat after 17 years, I did not have any leaks; I just replaced the Sunbrella to make it look new again. Here’s how you do it. Clean both sides of the rubber because you will have to seal it with silicone later. Cut open the inner tube to make a flat piece of rubber. Wrap it around the mast (4″ above the deck collar) and the deck collar using the big hose clamp to hold it in place and make sure that you overlap at least 3″ on the wide side of the mast. Stretch the rubber as you do it to make a tight fit around the mast and the deck collar. It will wrap on diagonal because the size of the deck collar and the mast is different. Do not worry about that you will cut the excess later. When you begin wrapping have a bigger size inner tube piece than necessary and start wrapping and pulling the end of the piece up or down to make a good fit around both the mast and the collar while keeping the whole piece smooth and flat. It took me a few tries before I got it right. Clamp the inner tube at the collar and the mast paying attention that the end of the overlap lays flat. By stretching in all directions you will achieve a perfectly flat end. Now that everything is tight and flat, cut the excess inner tube below the deck collar clamp and above the mast clamp leaving a little excess to keep it from slipping of the clamp. Now clean the mast above the boot and the deck collar below the boot. Also clean the rubber at the end of the overlap. Apply a generous bead of pure silicone on top, bottom and overlap edge. Smooth out the silicone bead with your finger and let it dry. Now make a boot to cover the rubber boot with matching sailcover material. Wrap it around the mast on top of the rubber and attach it with Velcro to close it and put a string in the hem at the top to tie it snug to the mast. That way the cover stays in place. Valois Nadeau (#096, Giva, ex-Gulliver).

b. Valois, how do you prevent the rubber from slipping while stretching it? Here is my understanding-so far. A new rubber inner tube, like a bicycle tube, comes folded flat in a box. If you unfold it and open it, the ring (or annulus) lies flat. Then, you can cut a part of the ring into an annulus segment, and it will lie flat. Then, you can cut the annulus segment along the inner diameter and along the outer diameter, and get two identical annulus segments, both of which will lie flat. Right, so far?

c. Yes. Now you are ready to attach the rubber to the mast. But, how do you prevent the rubber from slipping while stretching it? Put one hose clamp at the bottom or at the top and work it out to have a good fit. You do not need to stretch it very much. You just need to make it snug against the mast and the collar. Et voilà. You will have the best waterproof boot that costs close to nothing and will last for years; not to mention that it matches your boat’s canvas. Good luck. Valois Nadeau (#096, Giva, ex-Gulliver).

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.

a. See : http://www.boatus.com/seaworthy/rigging/default.asp

a. Jack, we chose a staysail without a boom partly because of the ease of removing the stay when not needed. I don’t know how you will handle moving the boom readily or dealing with the bulk and lines of a furler. We also chose to use a hanked on staysail to avoid this situation. We also have experienced the problem of tacking a large yankee through the space in front of the inner forestay. I have been told, and have had some experience to confirm, that tacking the yankee when the staysail is flying results in an easier operation, presumably from wind off the staysail. However, I don’t believe a staysail is recommended when beating. It comes into its own further off the wind. To remove the inner forestay I slacken the turnbuckle (by hand) and pull out the clevis pin which is a light friction fit (only slightly opened) and remove the clevis. Before going further I replace the clevis and pin in the turnbuckle. I have a parking spot for the inner forestay on the port rail (see below). When parked here it is tensioned by tightening the turnbuckle, with the clevis held by a captive pin shackle permanently mounted on the toe rail. [Lester’s Note: The shackle is to the right in the pic but is not shown.] I usually leave the running backstays set at all times, just slackening the leeward one and leading it forward to allow the mainsail boom the maximum travel. I have a Velcro strap holding the excess runner rope to the upper lifeline and another strap, attached to the runner upper block to loosely attach the runner to the aft lower shroud, out of the way (see below). My runners are tensioned by hand, using a 3:1 pulley system and a cam cleat on the lower block. I am sure that leaving the runners set up all the time is overkill unless one is in very high winds but since they are there I use them! Regards, David Salter (s/v #050, Opportunity).

How do I rewire my mast? Can you please help. I am trying to do some rewiring in the mast (Isomat): radar, coax, and a triplex wire for deck and steaming light. Are there internal conduits in the mast that extend below the side exit? Do I need to pull the mast? Gene Stoddard (#158, Swell Dish).

a. All masts are probably different. I have an Isomat clone (Cinkel Canada) and it has 3 extrusions inside the mast, 2 either side near the front and one aft.. They go the full length except that one or two (I forget which) are cut by the upper spreader supports. The extrusions each hold a plastic conduit tube and may be cut at whatever height one desires. I believe the only way to resolve wiring problems is to pull the mast. David Salter (Here’s my mast base, Pic 1) (#050, Opportunity).

b. We had an Isomat mast previously on our Corbin. It had two conduits, one fore and one aft. The wires within our conduits were bound together with cable ties every couple of feet or so. These wires flex snakelike back and forth across the conduit taking up much of the conduit space. We needed to take our mast down to get the wires out of the cable wraps and add another wire in the conduit. We disconnected all the wires, slid the entire bundle out, added a wire, attached it with cable wraps, slid the whole bundle back in, and reconnected everything. It was not as difficult as it sounded, and went quite smoothly. Hope that helps, Stephen Lefneski (#187, Toboggan).

c. I have an Isomat mast which I rewired several years ago. I had no conduits in the mast initially but Isomat sells various size conduits which can be slid up the mast from below into a retainer slot so they are fixed. In order to rewire your mast properly, and certainly to install additional conduits, the mast must be removed and put on sawhorses. Pull out all the old wiring and even remove the mast head temporarily for ease of pulling. Find the supplier of Isomat masts and accessories and purchase the new conduits you need. The conduits can be trimmed at the exact point where wires need to exit such as at the spreaders for spreader lights or radar domes before continuing on the the mast head. I would suggest signal wires be in separate conduits from the power wiring. If you have room in the conduit you might consider a spare wire for some future device or antenna you might want to install. Be sure to file smooth the holes where the wire exits the mast and that the wires are not pinched when exiting. All new wiring should be in double insulated sheaths and be tinned stranded wire of the proper gauge for the devices run. When the wires exit at the spreaders or at mast head they should exit at 90 degrees and make a slight bend down before heading back up again to the device. This will prevent water from entering the mast. Good luck with your rewiring. Jack Verheyden (#127, Kathrian).

d. There is no way you can deal with this mess without pulling the rig. The wires in the conduit will be impossible to pull out or use as pull throughs for new wiring. I rewired Two Pelicans mast down. The reason the wiring exit is higher than the conduit end is to form a drip loop. This exit would be the one to use for all the wiring including the radar if its cable is properly shielded. On deck I would mount an inverted U-shaped stainless steel conduit, one end attached by a flange to the deck where the wiring feeds below, the other end half the length of the U would be where the cables are fed in, then up and over the U and then down. With a suitably sized piece of pipe and a flange welded on the longer end you will have a barrier to sea water going below through the conduit. Plug the pipe after the wires are fed in, either with putty or with a piece of plastic tubing where the wires are fed through, one end inside the mast opening, the other slipped over the inverted shorter end of the conduit. Use the proper sized silvered copper wiring……expensive but a one time fix. Good luck, Jeremy Parrett (#101, Two Pelicans).

e. At the time most Corbins were being built, Isomat spars did not have conduits in them. Instead, they had two internal extruded tracks, similar to the sail track on the aft outside of the mast tube. Isomat would take the appropriate lengths of mast wiring, secure miniature slides every 12 – 18 inches along them, then “hoist” the wiring harness in one of the internal tracks, while fishing wires out of the mast tube at appropriate locations. With more complex wiring harnesses, they would split the bundle into two harnesses and use both internal tracks. There is no way to adjust the wiring on a setup like this unless the mast is unstepped. You may have something that’s been retrofitted, including a conduit (you should be able to see fasteners on the outside of the mast tube used to hold the conduit in place). In some cases, where advanced planning was employed, it may be possible to fish new wires through a conduit while the mast is stepped, but it is always easier while the mast is laid flat. In any event, your biggest issue may be the exit plate on your mast; a non-standard fitting for an Isomat spar and one I’ve never seen before. Good luck, Chris Reynolds, former owner of #083, Tamalmar, Corbin 39 pilothouse cutter.

f. The rewiring of a mast is much, much easier done with the mast down, especially if you are going to replace all the wiring. That being said, many times the wiring is filled with 3M 5200 at the base of the mast to prevent water from entering. To get wires out of 5200 is not an easy task if you don`t have access to it. There are internal conduits but the radar wire was big and often times did not make it inside the conduits. The radar cable usually goes out at the 1st spreader so it is about 20`long. Again, May I suggest that the mast be taken down for re-wiring. Have a wonderful day. Marius Corbin

Any idea where I might find a mast exit plate for my Corbin ketch? Stephan De Blasio (#176, Gisela)

a. Stephen, What is different about it and a standard plate? Lester, “I’m not sure. I walked into West Marine with the old one and they acted like I had a third eye. It’s made of plastic or bakelite and is curved. They suggested I try DuFour.” It’s a halyard exit plate.

b. I don’t know if this will help or not but you might try Hall Spars on the web – Try Hallspars.com I think… Question – is this a halyard plate or a wiring plate? Good Luck – Tom & Melod on Tiaga

c. This would be supplied originally by your mast manufacturer. Mine was made by Metalmast, they are or were located in Putnam CT. Tim O’Neil (s/v Whaleback) of Boston.

d. We have stainless mast exit plates on our mast. Schaeffer calls them Halyard Exit Plates and had them in 3 sizes in stainless in my 1993
catalog. Part nos. were 34-46, 34-48 & 34-49 for the largest. West Marine have them in the 2004 catalog, p.1055, P/Ns 149492, 163857 & 285470.
Regards, David (s/v #050, Opportunity)

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

How do you brace your mast at the deck?
a. see photos below for typical arrangements (they will open individually if you click them):

Who manufactured the Corbin bowsprits and if they are still available. Mine has some small cracks and I am considering whether to repair or replace it. Sim Hoggarth (#143, Alianna)

a. Sorry, I do not know. Mine is in good shape. If I was him I would call a marine stainless fabricator for a repair Stephen Lefnesky (#187, Toboggan).

b. The original bowsprits were made of stainless steel by a company called Tops . Tops was located in Michigan, I think; not sure where or if they are still in business. Mike Cashin (#045, Sea Dream).

c. Some of the Toronto area owners had bowsprits made by Klacko Spars. I imagine they could repair or replace your unit. They also made a lot of other stainless steel parts for the Corbin. http://www.klackospars.com/ Regards, David Salter (#050, Opportunity).

d. My wife Wendy and I have a Corbin 39, hull number 195 -a PH-CC. We bought our boat in Nassau Dec. 2010 and keep it at Grand Bahamas. I expect that we have the same bow sprit. I do not know who built it. Shortly after we bought our boat we had to have the bobstay replaced. The bobstay had been a threaded rod. We replaced it with a combination of rod and chain (at the water). A welder/machinist in Marsh Harbour, Abacos did the work for us. David Hibbard (#195, Endorphin).

e. While I was on the hard in Beaufort NC (Bock Marine) during 2006, I found a 1/4″ wall 3″ in diameter SS bowsprit from an old Abekin Ramussen ketch that had fallen onto the ground. Haggling with Kenny Bock……for $350 it was soon on the ground under Two Pelican’s bow!! It weighed a ton. I shortened and sleeved the ‘arms’ so we could align it to the Corbin’s hull before welding; built a scaffolding to sit it on and then bolted it on . There are 8 x 3/8″ bolts on each attachment plate, through bolted into the fwd deck locker above the airex core, backed up with equivalent sized 3/8″ thick backing plates!! I used an old chainplate welded to a fitted 12″ x 12″ ss plate to secure the bobstay which is a 1″ ss solid rod. The end of the chainplate pokes through the hull while the plate is well expoxied into the inside of the hull. A bead of 5200 around the protruding chain plate finished the job. Moving the whole foretriangle fwd 48 inches has eliminated all the weather helm. I removed the staysail boom; moved the staysail inner stay at deck level to the old forestay fitting at the bow, and fitted a new attachment higher up on the mast. I now have a very useable inner foretriangle as well . Two deck tracks for the sheets finished the job. Fair winds and calm seas, Jeremy Parrett (#101, Two Pelican) [Editor’s Note: The headstay will try to pull the bowsprit aftward. You must secure the sprit very securely to the hull and to the deck to prevent this from happening.]

f. See photos of (#069, Joint Effort).

g. The name of the company that did the bowsprits was Tops-In-Quality in Michigan I think…. I do not know if they are still in business. Have a wonderful day. Marius Corbin