NEW SHEAVE SLOT FOR MAIN MAST

Comment

Comment by bob mitchell on August 9, 2016 at 3:55am

CAPTAIN CLYDE'S COMMENT

     "I never like the way the then modern technology was used at the halyard sheave area on the masts.  The masts were built and the heads were carved out to fit the head fittings.  The sheave slots were cut out and the masts were fiberglassed, which covered the sheave slots.  The fiberglass was cut away from the slots and the head fittings were mounted and the three bolt holes drilled.  Here's the problem I saw: the slots were raw wood.  The "waterproofing" that was applied to the inside of the slots was nothing more that some of that latex concoction smeared all over the raw wood and over a wee bit of the fiberglass.  Side to side, what we had was the fiberglassed outside of the mast, a hole for the center throughbolt the hole of which remained raw wood.  Its inside waterproofing has been compromised by drilling the center bolt (the sheave axle) hole.  Now, here's a wrinkle: I changed the "plywood rabbet" in this area by removing it.  This increased the fore and aft thickness of the solid blocking at the head, and it became the "rabbet" for the upper two or three feet of the head.  So some of the masts had the "plywood rabbet" and some didn't.  I have no record or memory of the boat on which I made the change so what you found is what you have.  After all this I think the source of water that started the rot at the head entered either in the bolt holes or the inner surface of the slot where the latex (or whatever it was) that may have separated from the wood or was worn through by the turning sheave.  Here's another out of sight out of mind situation and that area may have never been looked at during all the years of use."

          This particular mast is from Le Bateau Sans Suci, a west coast boat before Clyde's time building Newporters, so it has the plywood attached to the fore and aft staves to form a rabbit. The rabbit aligned all four mast staves during assembly.