Air in tubes

[pugbro]

As I said earlier I am rebuilding a 20ft pontoon boat. I have the boat down to the bare essentials (tubes) and noticed a plug about 6ft from the front of each tube and another one about 6ft behind that one. I tried to loosen one of the small red plastic plugs and it came right out with only finger pressure.
When I removed the plastic plug there was a little air pressure released. Nothing major just a little "whoosh". Is this normal? Do the tubes require some air? Why two plugs?
I guess on the positive side, if its holding air, there should not be any leaks!
Any comments are appreciated!

KEEP IT FUN--KEEP IT SAFE

 

[blackcat650]

Re: Air in tubes

The caps should be for leak testing the tubes. The reason there are more than one is because the tubes are usually sectioned off inside. In case you rip a hole in one part the other should still float. I have heard not to use more than 3 to 4psi when pressure checking or damage could occur.

 

[5150abf]

Re: Air in tubes

We get requests for his all the time, it is simple science.

The tubes on your boat are a displacement hull, how much air is or isn't in the tubes has no effect on how they float, if you put a 20 pound vaccum on the tubes they would float exactly the same.

Those are to air check the tube at the factory to make sure all the leaks are repaired and black cat is right, a tube will pop at more than 6-8 psi, they are designed to hold pressure from the outside in not the other way around.

 

[pugbro]

Re: Air in tubes

Thanks a million for the info..Being dumb, fat, blind and ugly when it comes to boats, I know some of my questions sound stupid, but as my Dad used to say,"the only dumb question is the one you dont ask!"

Thanks again

Have fun, Be Safe!

 

[5150abf]

Re: Air in tubes

I agree with your dad, you can't learn anything if you don't ask.

 

[Splat]

Re: Air in tubes

Didn't see this answered,

The whoosh of air was also simple science. There was temperature difference of slightly warmer when you removed the cap than when they were installed at the factory. It's like leaving a sealed up gas can outside in the sun, it builds pressure as the air and fluid inside heats and expands.

Bill