how do you figure out how buoyant a wet suit is?

[diverdude74]

I have recently purchased a new XL 7mm Henderson Thermoprene farmer john (7mm over my core) wet suit and i was wondering if any one knew how buoyant the suit is, or how i could figure out how much weight i would need to compensate of the buoyancy of the suit.
-Doug

 

[eponym]

In a pool, wrap a weight belt around the middle of the suit and add weights to the end of the belt until the suit is pulled below the surface. Be sure to shake out any trapped air.

-Bryan

 

[Lee Taylor]

what Bryan said

 

[Matt83]

I would start with about 10% of your body weight pluss 5 lbs. Then you can go from there. It really depends on a lot more than just the suit. For example, your body type, what tanks are you using, fresh or salt water, etc. The best bet is to find a pool and some weight and figure it out while you have time to play around. You may also want to keep in mind that the buoyancy may be different and you may have to play around with where you want your weight. When I got a new 5mm suit my ankles were very floaty so I had to adjust what weights go where. So, jump in some water and do a good weight check before diving. Have fun!

 

[Jim Lapenta]

What you just got told was info that should have been covered in your OW class and demonstrated to you in at least one of your pool sessions. In fact a proper weight check should have been done in every session. If it was not you have to wonder what else you did not get taught that you should have? The weight check in the pool is the only good way to start. How the suit fits, that it is new, what your body type is, etc all will come into play. How much buoyancy does your other gear have. Many jacket bc's have 4-6 lbs inherent themselves, a BPW none or may be a bit negative with a wing fully empty. Go back and ask your OW instructor what else did he/she leave out of your class that you now want since you paid for it.

 

[spectrum]

I agree with Jim that you need make an in the water evaluation will all of the gear on. There are way too many variables in getting to the answer. Ideally once it has time to saturate to remove any stow-away buoyancy. Having the cylinder at 500 PSI is ideal, otherwise you need to subtract the weight of the air in excess of 500 PSI.

Now... getting back to you your basic question. You can get the item into a mesh bag and see what it takes to make it go neutral at depth X. That information can be useful in swapping between items. I have 2 hooded vests for instance, a 3mm and a 7mm that I wear with the same suit. Going between them is easy when you know the relative buoyancy. For the numbers to be any good again you need to make sure things are saturated with no trapped air.

My favorite weight check is to get to the end of the dive when I'm back in the shallows in 6-10 feet of water with ~500 PSI. I vent any remaining BC air and confirm that I am neutral. I will set things up so I can remove weight in small increments and see what happens. When you don't have enough it's very apparent and you just take a step back. If I can comfortably hover at that depth with an empty BC I can mace a controlled final ascent by managing lung volume. If you're not ready to do that then keep 2 extra pounds. Once you have a few good baselines and understand cylinder buoyancy, fresh water/salt water and your other gear properties you can mix and match on paper and hit the requirement pretty close. Nothing beats a final weight check to correct for compounded rounding errors.

The objective is to have enough weight to let you make a controlled ascent at any time. The defining point is at the end of the dive when your tank is down to ~500PSI and is at it's greatest buoyancy.

Pete

 

[diver 85]

What you just got told was info that should have been covered in your OW class and demonstrated to you in at least one of your pool sessions. In fact a proper weight check should have been done in every session. If it was not you have to wonder what else you did not get taught that you should have? The weight check in the pool is the only good way to start. How the suit fits, that it is new, what your body type is, etc all will come into play. How much buoyancy does your other gear have. Many jacket bc's have 4-6 lbs inherent themselves, a BPW none or may be a bit negative with a wing fully empty. Go back and ask your OW instructor what else did he/she leave out of your class that you now want since you paid for it.

but keep in mind, some instructors are not the sharpest shovels in the sheds.....

 

[diverdude74]

What you just got told was info that should have been covered in your OW class and demonstrated to you in at least one of your pool sessions. In fact a proper weight check should have been done in every session. If it was not you have to wonder what else you did not get taught that you should have? The weight check in the pool is the only good way to start. How the suit fits, that it is new, what your body type is, etc all will come into play. How much buoyancy does your other gear have. Many jacket bc's have 4-6 lbs inherent themselves, a BPW none or may be a bit negative with a wing fully empty. Go back and ask your OW instructor what else did he/she leave out of your class that you now want since you paid for it.

this was taught in my ow class i was just trying to get a starting point for when i do a weight check

 

[Scott L]

What you just got told was info that should have been covered in your OW class and demonstrated to you in at least one of your pool sessions. In fact a proper weight check should have been done in every session. If it was not you have to wonder what else you did not get taught that you should have? The weight check in the pool is the only good way to start. How the suit fits, that it is new, what your body type is, etc all will come into play. How much buoyancy does your other gear have. Many jacket bc's have 4-6 lbs inherent themselves, a BPW none or may be a bit negative with a wing fully empty. Go back and ask your OW instructor what else did he/she leave out of your class that you now want since you paid for it.

I am sure bouyancy and good trim are also covered fairly well in OW class. Does that mean a student can then pass a UTD or GUE fundementals class? Most all skills learned in the best OW class can be further improved upon IMO...