leaking holding tank

BrianConley · #1 (**permalink**) 05-31-2001

The plastic holding tank for the head, on a boat I just bought, leaks around the lowest fitting. Looks like stress cracks around the connection, I would guess from a prev owner twisting it to try to get a hose off. Attempts to repair have evidently been made with some type of epoxy, but still leaks. Does anyone know of a sure & permanent way to repair this. I really don''t want to replace the tank, looks like a custom fit.

clayton · #2 (**permalink**) 06-01-2001

If the tank is polyethylene, which I suspect it is, nothing will plug the leak. The fittings were heat welded on by spinning them to create friction melt. Your best bet is to bite the bullet and replace them. When I did I used Sealand - they are the best. Good luck.

navtron · #3 (**permalink**) 06-02-2001

I had luck on some tanks to stop leaks by heating a screwdriver hot and carfully melting the plastic next to it and dragging it over the crack..then marine-tex or boat-life...etc.

hgreen64 · #4 (**permalink**) 06-04-2001

I had the same problem on my 1983 Allmand 35. My tank was inaccessible also as with many boats are built from the hull up. I decided against a repair attempt, nothing like having that go bad on you in the middle of a cruse. You can see photos of my amateur but functioning repair at this website. http://www.allmandsail.com/holding_tank.htm

Hank Green
www.allmandsail.com

RobHoman · #5 (**permalink**) 06-04-2001

I would be most hesitant to try and repair a polyethlene tank that has a crack in it. It is highly unlikely that you will be able to actually repair the cracks and you will find that virtually nothing will seal the cracks for long.

I have had the same problem with my water tank in the nose of my Morgan 33 OI...it has a leak around one of the top fittings.... leaks whenever the water sloshes.....and I have put just about every adhesive known to man on the leak....none have worked. The only thing that has stopped the leak has been to drain the water tank. I''m currentlly getting ready to replace it.

Given the potential health risks that go along with a holding tank leaking or a fitting breaking off and the tak draining into your boat and the bilge......I would think it would be in your best interest to
replace the tank asap...even if it is difficult and inconvenient.

BrianConley · #6 (**permalink**) 06-08-2001

Well, if I may be so bold as to answer my own question... I found that polyethylene tanks can be welded by a process called plastic thermo welding. Had a guy in a plastic fabrication company do a very nice repair, cutting out the old & fabricating & welding a new piece in place. I was v happy to give him the $75 he charged me. Might be useful info for anyone with a similar problem.
Brian