Water in boom

Strico

New Member
We were given an old Sunfish by friends, and I've just decided to learn to sail it. I cleaned everything today and ordered sail clips and a bag for the mast. When I lifted the boom, water sloshed from one end to the other, despite both ends having their plastic end caps. They seemed pretty well stuck in place. How did the water get in? How to get it out?
 
Oddly, many Sunfish booms get water in them, probably through holes in pop rivets that have not been sealed. Drill a small hole in the outboard plastic end cap and screw in a small round head s.s. or brass screw. When you detect water, unscrew the screw and drain.

A. Glos
Cazenovia, NY
 
Water will force it's way into the booms under pressure -- i.e. when they're under water. Especially if the boat's been upside down ("turtled") a lot -- the water pressure is significant down where the ends of the mast and upper boom are (maybe 10' - 15' ?). Anyways, water can get in around very slight gaps between the mast and end caps, at the eye bolt locations, and the pop rivets that mount the blocks on lower boom.

Best bet is to gently work/pry those end caps off, drain the water and dry the booms out, and then seal the caps with a bead of silicone around the cap's shoulder when you reinstall them. You can also try silicone at the eye bolts and pop rivets.

Note: Remove the old corks inside if you want (originally used to seal off the booms so water getting in at ends couldn't flood the whole boom) -- they're usually falling apart/rotted and don't hold back the water once they get old. You'll sometimes find significant corrosion under/near them as well...
 
I agree with all of this except I replaced the corks and caulked then in the ends of the mast about 2 inches inside the plastic caps as backup seals incase the caps ever leak.

I did the same with the spar and boom.

Secular



Water will force it's way into the booms under pressure -- i.e. when they're under water. Especially if the boat's been upside down ("turtled") a lot -- the water pressure is significant down where the ends of the mast and upper boom are (maybe 10' - 15' ?). Anyways, water can get in around very slight gaps between the mast and end caps, at the eye bolt locations, and the pop rivets that mount the blocks on lower boom.

Best bet is to gently work/pry those end caps off, drain the water and dry the booms out, and then seal the caps with a bead of silicone around the cap's shoulder when you reinstall them. You can also try silicone at the eye bolts and pop rivets.

Note: Remove the old corks inside if you want (originally used to seal off the booms so water getting in at ends couldn't flood the whole boom) -- they're usually falling apart/rotted and don't hold back the water once they get old. You'll sometimes find significant corrosion under/near them as well...
 

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