Water proofing at the mast-deck joint?

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).