Diving Dry...is it bouyancy control?

[Quarrior]

I think learning how to use the suit as a back up is a good idea. I don't like the idea of using the suit as a primary. As stated earlier, to many places for air to hide and to slow to vent.

 

[diverdan214]

i control bouncy with drysuit and my lung(s).

As do I, I find it much more intuitive to manage one air bubble than two (or two than three I guess). Never had much problem, but then I am a noob.

I wonder how much this is a cultural thing. Most people I know who learned DS in Europe seem to use DS for bouyancy, the only person I've seen diving dry from the States over here and most of the posters on here (from the States) seem to go with BC. This is one of a number of differences I've noticed from diving on both sides of the pond, and have heard good arguments for doing things either way. It's funny how different ways of doing things become dominant in different parts of the world even for a practice as relatively young as Diving. And of course people always have compelling reasons for why they do things the way they do.

Since PADI & NAUI both have training material suggesting that the drysuit be used for buoyancy I teach it both ways and suggest that people figure out what works best for them.

Giving your students freedom to choose albeit informed by your experience sounds a bit radical. This freedom thing scares and confuses me.

 

[The Kraken]

Dry suit = thermal protection an squeeze relief
B/C = Buoyancy control

the K

 

[Scubar]

Dry suit = thermal protection an squeeze relief
B/C = Buoyancy control

Same here.

 

[spectrum]

The less air in the suit the better. Enough for warmth/comfort and that's all.

The buoyancy with the suit scheme is so bizarre that several local intructors I have spoken with pretend it does not exist.

Pete

 

[MikeFerrara]

A few posters have pointed out that in rec gear the amount of gas needed to take care of the squeeze is about what's needed to get neutral so it isn't a big issue one way or the other.

I was originally taught to use the suit and never had a problem until...I took an entry level tech class and went for a dive with a heavy set of steel doubles with lots of gas...at which time, I almost got hurt because I was taught this nonsense of using the suit for buoyancy control. I raised my head a bit, for some reason or the other, and all the air bubbled out my neck seal and DOWN I WENT! Well right then and there I invented a new way of controling buoyancy with a dry suit...I started using the BC. Imagin that.

There is another little issue in using the suit that I haven't seen mentioned and the agencies certainly haven't figured it out. they tell you to use the BC at the surface. They tell you to dump all that air to descend and to then use the suit. the problem is that in order to do a nice controlled descent, you don't want to dump all your air at the surface but rather just enough to get slightly neg which often would leave you with some air left in the BC. When and if the rec agencies ever learn how to do or teach a very controlled descent, they'll better understand saome of the problems assiciated with how they teach dry suit use.

 

[jiveturkey]

I raised my head a bit, for some reason or the other, and all the air bubbled out my neck seal and DOWN I WENT!

I use the BC so it wouldn't normally affect me but I never even considered this happening before. Hopefully you didn't drop too far.

 

[diverdown247]

Using the dry suit for buoyancy isn't a good idea. Supplement the BCD, sure, but not primary.

Air can get in the legs and cause you to flip upside down. Then you have to figure out how to "tuck and roll" to get the air back up to the top of the suit. Although this can happen at any time, it's more likely with more air.

 

[SteveAD]

A few posters have pointed out that in rec gear the amount of gas needed to take care of the squeeze is about what's needed to get neutral so it isn't a big issue one way or the other.



There is another little issue in using the suit that I haven't seen mentioned and the agencies certainly haven't figured it out. they tell you to use the BC at the surface. They tell you to dump all that air to descend and to then use the suit. the problem is that in order to do a nice controlled descent, you don't want to dump all your air at the surface but rather just enough to get slightly neg which often would leave you with some air left in the BC. When and if the rec agencies ever learn how to do or teach a very controlled descent, they'll better understand saome of the problems assiciated with how they teach dry suit use.

In typical rec configuration the diver should be weighted such that dumping all air from the bc will allow you to descend, not cause you to drop like a stone. Why would you want to be so heavily weighted that that you're leaving the surface with air still in the bc?

That said, in tec configurations with large capacity doubles and stages, where there is the possibilty of up to a 20 pound weight change due to gas consumption it may be necessary to be 20 pounds "overwight " to ensure adequate weighting at the end of a dive.

In short use the right tool for the job. if there is no need for a "big bubble" simply preventing squeeze maintains bouyancy, if there is a need to offset 20 pounds of consumables use the bc.

 

[MikeFerrara]

In typical rec configuration the diver should be weighted such that dumping all air from the bc will allow you to descend, not cause you to drop like a stone. Why would you want to be so heavily weighted that that you're leaving the surface with air still in the bc?

Even in a rec configuration your liable to be 6 pounds or so neg with a full tank (assuming an 80 cu ft tank). Do you need to be six pounds neg to descend? I don't think so and that means that you don't need to completely dumping your BC at the surface especially since your only going to be picking up speed as you descnd util you start adding gas.

Regarless of the amount of breathing gas carried, the only time you need to completely dump to descend is when you have an empty tank and that's a silly time to be descending.

To start a nice controlled descent, get neutral and exhale which leaves the BC buoyant buy an amout roughly equal to the weight of the gas carried. An object that's 6 pounds negative pretty much drops like a stone more than it does like a diver...especially if it's vertical and not offering much resistance rather than nice and horizontal.