Water in the mast....leaks inside

[Dave22q]

Originally Posted by suenodelmar

I had this problem with a deck-stepped mast on my Downeaster 38. Rain water would enter the mast through the myriad of holes. There was no practical way to stop it from entering. The water would then seep through the wiring exit holes, pass through the mast foot and the deck, and damage the compression post and bulkhead. The solution was to drill two half-inch holes on opposite sides of the mast, located about two inches above deck level. I vacuumed out the accumulated crud with an angled snout attached to a shop-vac.. Then, I injected self-leveling caulk available at Recreational Vehicle supply stores. Ordinary caulk like 3M 5200 or Sikaflex is too viscous and will not flow to fill the gaps. The self-leveling caulk must be injected in several layers because if a single, deep layer is injected, it may take several weeks to completely dry. I was able to fill the base of the mast up to the level of the bottom of the holes with three injections allowing about two weeks of drying time for each layer. Thinner layers may have dried faster. Now, when water enters the mast, it flows harmlessly out the holes onto the top of the deck. The interior of the boat is FINALLY dry!

Seems like the weight of a single layer would better seal your bottom holes. Why is curing time an issue? Once in the mast your calk is not going anywhere.