Polyolefin - neutral buoyancy - eh, not so much.

[Kharon]

While at Roger's Rock this weekend I decided to do an experiment. I took all my exposure suits and my weights out to about waist deep and carefully sank them till they were neutral. I made sure to get all the internal air out of arms, legs, etc. My 3 mm full suit took 6.5 pounds 2.5 mm shorty took 3.5 pounds, 3mm vest took 3 pounds. But to my surprise my Henderson polyolefin (advertised to have zero buoyancy) took 1.5 pounds and my Hyperflex polyolefin (same claim of zero buoyancy) took 2.5 pounds. That's not neutral buoyancy folks that's hype.

 

[Altamira]

That surprises me because when I use the Henderson poly skin under my wetsuit, I do not need any weight adjustment. But the skin may take a short time to release any trapped air immediately after submerging.

 

[tbone1004]

polyolefin=polypropylene or polyethylene, both are less dense than water, ergo floats. It will not compress so has no buoyancy adjustments, but it isn't that much. Density is ~0.95 against water which is 1, or sea water which is 1.025. They're going to float. Not much, but enough

 

[Altamira]

Thanks Tbone1004. Since it does not appear to add any weight above what I use for wetsuit, I will continue to use it because it makes donning the wetsuit a lot easier.

 

[Kharon]

polyolefin=polypropylene or polyethylene, both are less dense than water, ergo floats. It will not compress so has no buoyancy adjustments, but it isn't that much. Density is ~0.95 against water which is 1, or sea water which is 1.025. They're going to float. Not much, but enough

Between the two of mine it's an additional 4 pounds even after soaking and squeezing the air out. I wonder if I'm doing something wrong - experiment wise. I also find that I don't need to adjust my weight that much when I wear them as opposed to not using them. Confusing. Guess I'll just go with what works instead of overthinking.

 

[stuartv]

Maybe when it's worn under a wetsuit it is compressed just enough to eliminate its natural buoyancy?

 

[tbone1004]

polyolefins do not compress, they are plastic, not foam. They are also completely hydrophobic which is why they dry so fast, no water to absorb and then release.

 

[stuartv]

polyolefins do not compress, they are plastic, not foam. They are also completely hydrophobic which is why they dry so fast, no water to absorb and then release.

Do they hold air (as in, microscopic bubbles or pockets)? Would wetsuit compression squeeze a little bit of that out?

 

[tbone1004]

no, they are solid, mostly crystalline polymer structures. The extrusion process ensures there is no air pockets inside of the fiber as that would create weak points in the fiber and that would be bad.

*disclaimer, polyolefin extrusion is a large part of what I do for my day job...*

 

[Doby45]

*disclaimer, polyolefin extrusion is a large part of what I do for my day job...*

Then I think you are duty bound to make us some sweet undies outta this stuff. Make mine extra medium, thanks!