Air in Pontoons?

[554937]

I just bought a 1972, 24Ft pontoon and they have a few small leaks that I have found while trying to air up the pontoons. I am in the process of getting the leaks repaired but need to know the best way to find all leaks and just how much air I should put in each pontoon. And how long does it take to air up a pontoon of that size. I have an industrial air compressor and want to make sure I get it right and most importantly I want to make sure that what we are doing is the safe way. Thanks
John Guy

 

[Jeep Man]

Re: Air in Pontoons?

Check out the sticky at the top of this section. It's an accurate depiction of what too much air will do. Pressure should be 6 or 7 lbs., and possibly lower considering the age of your vessel. A soapy solution should show the leaks.

 

[5150abf]

Re: Air in Pontoons?

Define"while trying to air up the toons"?

The only reason you put air in tubes is to find leaks, if you are trying to get them to be more buoyant that doesn't work.

The ONLY way to increase flotation is to increase the displacement of the tube, they will have the exact same flotation whether there is a 10 psi vacuum or 10psi positive pressure because they are the same size.

Jeep man is right, 5-7 psi max, no need for any more and use soapy water in a spray bottle, we actually use Polmolive dish soap at work.

I use more pressure at work because the leak test is also a quality check, if they can't take a little air I don't want them in the field just like the tube in the top post, it had a flaw in the top seem weld and failed the pressure test.

I have the luxury of just telling someone to build a new one though, if you blow yours up you are in for about $1500.00.

 

[ridefst]

Re: Air in Pontoons?

The ONLY way to increase flotation is to increase the displacement of the tube, they will have the exact same flotation whether there is a 10 psi vacuum or 10psi positive pressure because they are the same size.

Firstly - you're completely correct

Secondly - I got curious and had to calculate a few things...
Weight of 1 cu/ft of air at 60 F = 0.076 lb
Cubic feet inside a 24" diameter x 24' long pontoon = 75.4 ft^3
Weight of the unpressurised air inside one pontoon = 5.75 lbs
Weight of 1 cu/ft of 10psi air at 60 F = .128 lb
Weight of one pontoon at 10psi = 9.5 lbs

So, pressurising your pontoons to 10psi each would add about 7.5 lbs to the weight of your craft, causing it to float slightly lower in the water.
Pulling a vacuum and removing all the air would take away 11.5 lbs, letting the craft float a little higher.

Ok, this was off topic and all theoretical, and won't make any difference to anybodies boat, but I was curious and now you and I both know.

 

[5150abf]

Re: Air in Pontoons?

I was going to mention air had weight but I didn't know it was that much very interesting.
I will keep you in mind for all my complex mathematical problems.

 

[ftl900]

Re: Air in Pontoons?

So I could fill them with... helium?? j/k

 

[5150abf]

Re: Air in Pontoons?

We actually had someone wanted us to weld air fittings on there boat so they could put helium in the tubes.

Never mind the tubes weigh more than the tank the helium came in, I imagine it might lighten the boat a couple pounds but not nearly worth the trouble and expense adn no we didn't do it.

 

[boat1010]

Re: Air in Pontoons?

I had a friend that didn't believe me that SCUBA tanks do not float when full. He was so sure of himself that he threw his in the water just before the dive. He wasted a 80 foot decent and bottom time going to get his tank that was sitting on the bottom. And yes they do float empty.