Wrestling with dry suit buoyancy

[RIdiverMike]

Scott and NC Wreck Diver got me to thinking when they mentioned a tight bc or tight bc waist strap. I'll definitely try loosening the waist strap but I'm also wondering whether the shoulder straps of my jacket bc are contributing. Maybe a general loosening of waist band and shoulder straps are in order. While I see more drysuit divers with plates/wings or rear inflation bc's, I've never heard that you can't use a jacket style with a drysuit.

Thanx all for your ideas - good things to check and try!!

Cheers,
Mike

 

[HBDiveGirl]

Scott and NC Wreck Diver got me to thinking when they mentioned a tight bc or tight bc waist strap. I'll definitely try loosening the waist strap but I'm also wondering whether the shoulder straps of my jacket bc are contributing. Maybe a general loosening of waist band and shoulder straps are in order. While I see more drysuit divers with plates/wings or rear inflation bc's, I've never heard that you can't use a jacket style with a drysuit.

Thanx all for your ideas - good things to check and try!!

Cheers,
Mike

I dived a drysuit with a good BC (SeaQuest Balance) for about a hundred dives in 6 months...before switching to a backplate/wing. I dive positioned horizontally in the water column.

You can absolutely do it... but the BC does not help you manage the gas in the suit the way the BP/W does. With less compression against my back, the BC allowed lots of gas to move there. The plate eliminates that space and keeps gas elsewhere in the suit instead.

By the time I switched I had gotten pretty good at diving the d.s. with the BC, but it got much easier with a plate.

Idea for non-custom drysuit wearers (like me): I start each dive with a surface maneuver to reposition the suit before descending. (It shifts down as I walk or get through the surf.) I lie face down on the water with my reg in, close the shoulder dump valve, and inflate the suit. Really inflate the suit until I can feel my legs moving freely inside the gas-filled suit. Then I stretch my legs and arms into the biggest "X" I can manage and wriggle until the suit is fully extended (I have a DUI with a telescoping torso.) Staying face down, I open the shoulder dump valve all the way and rotate slowly to upright vertical in the water. The gas exits the suit and it's now press-fitted to me in a relaxed state.
It stays this way the entire dive and I'm dramatically more comfortable.

I call it "The Raul", in honor of the very nice PNW diver who showed it to me.

At the start of each dive, Ken's used to me saying, "Gimme a minute to Raul the suit....".

And then we dive.

It all gets easier. Don't give up.
I wasn't in love with my drysuit until the 49th dive I did on it.
A thousand dives later, I still love it.

Good luck!

~~~~~
Claudette

 

[RIdiverMike]

Thx Claudette - I'll definitely try the "Raul". Actually sounds something similar to what someone showed me at the DUI demo and admit I haven't done it since. Appreciate the words of encouragement too - so far the ds has been discouraging at best and of course the 100 ft/min ascent rates probably don't add to my life expectancy!

Best wishes.

 

[Randy43068]

Without seeing the problem, and from what you said about not getting air in the crotch area, I think two things about it.

1) it may be too big for you, allowing too much air into the thing
2) you are putting way too much air into it in the first place. Put ONLY enough air in it to take some squeeze off of you to allow movement.

I'm not suspecting the dump valve, and it's rare that your undergarment will block modern dumps.

Don't use it for buoyancy control. It's part of your thermal protection, NOT buoyancy control unless your wing fails for some reason.
Why they teach using the DS for buoyancy is beyond me and total lunacy.

 

[TSandM]

Dump valves can get sticky. The USIA rep here on this board gave me a great tip -- soak the valve overnight in distilled water, and then again overnight in water with a few drops of liquid Ivory soap in it. I have rejuvenated several sticky valves that way.

If the valve isn't working after that treatment, they are not horribly expensive or complicated to replace.

BUT -- you have to make sure you are actually getting the dump valve to the highest spot. Depending on where it is located, that can be difficult (although I don't think I've ever seen a DUI suit with a really misplaced valve).

With regards to the crotch squeeze problem -- it's very simple. Physics makes gas go to the highest point in the suit. If the bottom of the suit is squeezed against you, then your crotch is lower than your shoulders, no matter what you THINK about your position in the water. It is virtually impossible to tighten BC straps enough to keep air from migrating around in the suit (I wear a 20 lb weight belt cinched as tight around me as I can get it, and believe me, air has no problem getting to my feet ).

If you are truly horizontal and have gas in the suit, and your crotch is still uncomfortable, it is possible that the suit doesn't fit, and is simply too short for you from neck to crotch. You can diagnose that on land, by looking at the tension in the fabric when you are simply standing up, and by bending over to touch your toes. If you can't do it because the suit is binding, it's too small.

Buoyancy control in a dry suit is more challenging than with a wetsuit and BC, because the air bubble has so much more freedom to move around, so you really have to anticipate buoyancy changes and start venting the suit well before you think you need to. I think many of us have stories of yoyoing buoyancy and unplanned ascents, before we mastered the delicate art of drysuit management. (At least, I do!)