Would a boat float higher in the water if filled full of helium?

Question

Im working on a piece of equipment that has to be fixed to a floating tank, and was wondering if it would float better if it was filled with helium rather than air? (ignoring the explosive posibilties!)

It wont be moved around, and yes, I forgot that Helium isnt explosive, that would have been funny however! Should point out that the boat is really a big tank that floats, and equipment can be mounted to its top surface, its 15m x 6m and will be carrying over 30 tonnes!

Answer 1

Filling the tank or boat (or whatever) with helium will make almost no difference. Basically you're comparing the difference in buoyancy between air-in-water to helium-in-water (both are pretty much as buoyant as you can get). To illustrate the point: consider "filling" the tank/boat with nothing (i.e. vacuum) - that would be even better than helium, but you're basically getting 999kg/m^3 instead of 1000kg/m^3. It's not worth it.

You'd be much better off making a larger tank, or reducing its mass.

Answer 2

Yes it would float just a little bit higher.
As you fill a closed container with helium and place it in water you will have both the force of buoyancy of air in addition to force of buoyancy water to be concerned with.

Also helium, as you know, is not an explosive gas.

In responds to 'Additional Details'
You probably would add a few kilograms of displacement to your contraption by filling the tank or pontoon with helium.

Answer 3

No matter what medium you use to fill the (hermetically sealed) tank it is the MASS of the fill that determines the buoyancy.

For equal volumes helium, being less dense, would have a smaller mass.

By reducing the pressure (the volume being kept constant) the mass is reduced. P1 x V1 =P2 xV2 therefore if V1 = V2 (closed tank) reducing the pressure reduces the mass.

Less mass = Greater buoyancy. The tank will rise higher in the water.

Answer 4

Sure, unless you pressurise the Helium more than you would have the air. :)

Don't worry, the same pressure will give equal masses.

However, overall, unless it is a very small boat, it will not have that much effect.

And as for explosive possibilities..... Helium is the least reactive of all the elements. It will not explode chemically. (Though if you pressurise it enough it will go BOOM just like anything else... though only if it breaks the container it is in!)

Answer 5

If it was possible to contain all the helium within the boat - then the answer would be yes, because the boat only displaces as much water as the weight of the boat. Because it is filled with helium, the boat would be lighter than one filled with air.

Answer 6

Yes, but, how do you contain the helium? The container to hold the device would have to be leak proof, and may add weight, offsetting any other gains. Helium balloons, even in Mylar, do leak. How long does the helium have to stay.

If you have a tank to hold the helium, perhaps you might be able to pull it down to a vacuum, which would weigh even less.

Answer 7

Yes it would, and there aren't any explosive complications as Helium isn't explosive - you are probably thinking of Hydrogen with regard to the Zepplins, that is explosive and it was disastrous!

Answer 8

I would have thought it would float higher but that doesnt necessarilly mean better.
A boat should have ballast to make it handle better, otherwise it becomes skittish and more susceptable to wind interference.
Obviously if your equipment is not going to be moved or steered then try it. It would be good to see.

Answer 9

helium wont explode, its inert. hydrogen will though!

it would make it float easier but it would be unstable