Stopping water leaks at the compression post?

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.