How to practically measure float bouyancy

Aimrite sells the buoy for pound? :rolleyes1:

Aimrite vende la boya por libra?

Quote from Dan

Here's the bouyancy test for the Aimrite Reef float. As mentioned previously it's an older model but I was told the dimensions and stated bouyancy are the same as the current red/orange model; 39" long by 12" wide - 48lb.

The float was inflated by mouth as much as was possible. It had 37lb of lift in the pool. Multiplying by 1.025 to get saltwater bouyancy results in almost 38llb, 10lb less than Aimrite's stated bouyancy. After testing the Speardiver float this is more or less what I expected. Based on these tests and its dimensions I believe Aimrite's Bluewater float bouyancy will be significantly less than the stated 90lb.

Aimrite Reef Float Buoyancy Test - YouTube

I took the opportunity to retest the Speardiver float, this time without the ballast. It measured 43lb of lift. Multiplied by 1.025 results in 44lb bouyancy in saltwater. Same as the previous result.

Speardiver Spearfishing Float Buoyancy Test - YouTube

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i see one potential problem with how you are using the scale in the video it looks like you are holding it at a angle . a spring scale will give a lower reading if there is any side load at all on it, even a tiny bit of angle . to get a accurate reading hold it by a rope loop on the bottom of the scale .or to remove all doubt hand weights off the float until it goes neutral and compare that to the scale reading.
phil

Makes me wonder how aimrite came about there advertised numbers... Dan, does anyone at the pool ever question what your doing during these product tests/comparisons? I know I'd be curious if I saw such things going on.

Great looking float Dan, looks bullet proof.

Cheer, Don

Good test Dan. I believe that Rick claimed that float was rated at 80 lbs. I would like to see the same test on some other floats for comparison. Get to work:D

very well done...and i certainly hope you need that scale a lot in the future

I don't know how much difference it makes ,but 10# of steel won't weight 10# in water it will "float" a little .
Phil

Quote from phil herranen

I don't know how much difference it makes ,but 10# of steel won't weight 10# in water it will "float" a little .
Phil

You can subtract the volume of water that the steel take up using density of steel 7.85 g/cm3 and the density of fresh water 1.00g/cm3

10lbs steel x 1kilo/2.20lbs x 1000g/1kilo x 1cm3/7.85g x 1g/1cm3 x 1kilo/1000g x 2.20lbs/1kilo=1.27lb H2O

It is a small difference.

So if the float gives a buoyancy of 75lb with the steel plate in fresh water then subtract 1.27 pounds from it.