Cross Threaded Fittings.

[Dyk Luben]

My boat has a polyethylene tank for water storage. It has a 2 inch threaded plug that has been cross threaded over the years. Is there a repair for this so I don't have to replace the tank?On another note, upon removing the head discharge hose from the thru-hull, no water enters the boat, though the seacock is open. The head pumps overboard just fine. There is a 90 degree elbow at the thru-hull so I can't see what's going on. Do builders use one way check valves in thru-hulls or do I just have a blockage?Thanks.

 

[Peggie Hall/Headmistress]

Sounds like a blockage in your thru-hull

And yes, your tank can be fixed...although how easily depends upon whether you can do it by just replacing the plug (they're available at any hardware store) or it's the threads in the tank fitting that are all screwed up

 

[Sam Lust]

The open end is above water line !

The fact that it has a sea cock does not mean it is below the water line when the boat is at rest. It can and probably will submerge when the boat is heeled, hence the need for proper assembly and maintenence. Look for the simplest answer first. If you're still not convinced, open the seacock and try to blow through it.

 

[Dyk Luben]

More on crossthreads

Peggy, the threads in the tank are messed up, not the plug. What repairs are out there.Thanks,Dyk

 

[andy]

pipe thread tap

are you sure it isn't 1 1/2" pipe thread? most are. you could borrow a 2" pipe thread tap and run it in by hand to clean the threads if they are not too messed up. Use a liberal amount of teflon tape when reassembling. I have also used a steel or bronze fitting with hack saw cuts in the threads instead of a real tap.Otherwise - tank replacement time