Join Date: Dec 2004
Location: Alameda, San Francisco Bay
Thanked 67 Times in 66 Posts
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Re: Thru hull possibly leaking... what to do
Hnash - DO NOT LOOSEN THE RETAINING NUT WHILE THE BOAT IS IN THE WATER! Your problem is the bond line between the thru hull's outer flange and the outside of the hull has been broken. I can see how this problem originated. The original repairer did a nice job making flat backing plates so the retaining nut have a flat surface to mate. The problem lies with the elbows screwed directly to the stand pipe. When torquing the elbow to align with the hose there must of been some movement of the thru hull itself, breaking the caulk bond. The elasticity of the caulk have been preventing (or slowing down) the leak so far. The proper repair is to haul the boat, remove, recaulk, and reinstall the thru hull. The AYBC way is to use a right angle seacock that can be closed off in this application instead of a threaded elbow.
2000 Catalina 34 MkII