Bung hole under water line on pontoon? Help please?

[duganderson]

I had a leak fixed on my tritoon. The guy that fixed it recommended and added bung holes below the water line so I can drain the aluminum hulls/toons if necessary in the future. I, however, recently read that water can get sucked in past the rubber screw-in-plug when the air inside the aluminum hulls changes temperature. The mechanic that did this said this would NOT be a problem because the pontoons have "pressure relieve valves" on the toons.

Will I likely get a leak?

Do the "pressure relief valves" let air in AND out or only out. If they only let air out, I'm guessing the pressure could still suck water in.

If this is likely a problem, can they just weld the holes shut?

 

[metriccrescentwrench]

I don't know much about pontoons (except that most of 'em are slow :lol: ), but in the years that I've been boating I've never seen any significant amount of water get past a properly installed plug. IMO you're worrying about nothing. From a scientific standpoint any 'vacuum' built up inside a pontoon from heating/cooling cycles would only amount to a difference in pressure equal to a foot or so of water, so it's not like you'd suddenly see a huge pressure differential.

 

[jestor68]

Did the "mechanic" show you a pressure relief valve?

 

[H20Rat]

My last pontoon had welded pipe fittings w/caps on them on the tubes. Never once leaked. Put some teflon tape on them, get a decent wrench, and if you really want paint over the threads/cap with silver paint after the cap is tightened. It won't leak, ever!

 

[duganderson]

This bung hole is just a 1" pipe with a typical rubber plug like you would use on a fishing boat (the screw in type).


BTW.....We have a 150 and it can go 25 with 11 on board. Pretty good for a 'party barge.'

 

[metriccrescentwrench]

BTW.....We have a 150 and it can go 25 with 11 on board. Pretty good for a 'party barge.'

I'll probably be looking for a 'toon one of these days, my wife is liking my go-fast boat less and less. She goes into automatic nag above 30 - "Why do you need to go so fast???".

 

[smokeonthewater]

I think I would ask the "mechanic" what the heck he was thinking and have him fix his 'bunged' up job... replace the bungs with threaded pipe so you can put a real plug in instead of the rubber plug.