new 7mm suit too buoyant!!! What to do?

[opalobsidian]

Hello everyone!

I just got to try out my dandy new 7mm suit in Hawaii, which did a pretty good job of keeping me warm in those icy low 70s degree water, but the suit has a desire to pull me to the surface when I'm at about 20 feet. I can get past this issue on descent, and have no problems while diving below that depth, but while ascending it's a *****! Luckily in Hawaii the boats used mooring ropes that I could wrap myself around for my safety stop and controlled surfacing, but WHAT WILL I DO WHEN I DON"T HAVE THAT ROPE????

Thanks!
Pamela

 

[Rainer]

Um, add weight.

 

[under water]

Pamela,
It's a new suit, so not compressed much yet so it probably has more swing to it's buoyancy due to compression at depth. Like the previous poster said, you need more weight. It's physics. You are more buoyant after you use air than before so make sure you weight yourself for end of dive, not start of dive. Also, make sure you don't have excess air in BC.

 

[Brandon]

Um, add weight.

It's pretty much that simple. Another 2-6 pounds should do it.

Next time you dive, grab an empty cylinder and do a buoyancy check. Add weight until you float at eye level with air in your lungs and an empty bc. When you exhale, it should start a very slow descent. Dive like that for a dive or two, then make adjustments as you see fit.

-Brandon.

 

[opalobsidian]

Thanks, Brandon and Frank, for answering in a manner which is actually helpful!
Soooo, even though I am okay while diving with the amount of weight I'm currently using, I should add more weight so I won't shoot up during acsent, and then just inflate my bcd more during the dive itself?

Thanks!
Pamela

 

[fisherdvm]

It might be that you have not compensated for the extra 6 pounds of bouancy that you gain when you tank go from 3000 psi to 500 psi.

If you can descend, that means that you are short of 2 to 6 lbs - just like the other poster said.

Next time either do a buoyancy check with a near empty tank, or if you use a full tank, add an additional 6 lbs of weight.

 

[spectrum]

Thanks, Brandon and Frank, for answering in a manner which is actually helpful!
Soooo, even though I am okay while diving with the amount of weight I'm currently using, I should add more weight so I won't shoot up during acsent, and then just inflate my bcd more during the dive itself?

Thanks!
Pamela

Yes, you need to weight yourself for the end of the dive when your tank is the lightest. That is why you managed to get down but had difficulty controlling your final ascent.

Yes use the BC to offset the times when you are negative due to a plentiful air reserve and wetsuit compression. This is all entirely normal for cold water divers. That is precisely why you wear a Buoyancy Compensator.

Take about 5-6 pounds extra for the next dive and try to end with this weight check:
Remember to set your weight so that you bob vertically at eye level at the end of your dive with an empty BC, an average breath, your feet still (crossed) and about 500 PSI in your cylinder. A deep breath should get your mask out of the water and a deep exhale should sink your mask. Do all of this while breathing from your regulator. The end of the dive is the defining moment for your weight requirement and you want just enough to let you stay down in the shallows with a light cylinder.


Pete

 

[PerroneFord]

Now that proper advice has been given to the original poster, I just want to ask in all seriousness here.... was this not covered in your OW course? If there is one thing that seems to get done, even in poor OW courses, it's the idea of putting on plenty of weight (lead).

7mm expands pretty nicely through the shallows so you're going to get a real burst of buoyancy as you approach your final stop.

 

[SparticleBrane]

The next question--why a 7mm in low 70s? :11:

 

[SteveC]

The next question--why a 7mm in low 70s? :11:

Good point! The main reason to dive the tropics is so you don't have to wear a 7mm suit. Thick wet suits will always be harder to dive in than thin ones.