bcd vs dry suit for buoyancy

[lmackay]

Originally was trained to control buoyancy by inflating dry suit. Having now moved to Florida and started cave diving, I am now in the habit of only inflating the dry suit enough to prevent squeeze. Everything else to controlled using the buoyancy compensator.

What are your views on this?

 

[Mo2vation]

Originally was trained to control buoyancy by inflating dry suit. Having now moved to Florida and started cave diving, I am now in the habit of only inflating the dry suit enough to prevent squeeze. Everything else to controlled using the buoyancy compensator.

What are your views on this?

Hey buddy -

Although you only have 3 previous posts to the board, I'll spare you the "use the search feature" thrashing.

That said, you gotta do a search on this. In the universe of thoroughly, passionately, thoughtfully and lucidly addressed topics, with valid, reasonable, experienced and well crafted arguements on both sides, this one is easily in the top 10.

Enjoy the hunt.

OK everyone (mech diver, that means you) - now you can pile on.

K

 

[OneBrightGator]

Exposure suit for exposure, bouyancy control device for bouyancy.

Ben

 

[GDI]

In caves the BCD is used over the Drysuit because of it's ability to dump quicker than the drysuit. Caves do not allow you the luxury of movement that a open water environment has. Just enough air/argon into the suit to stop the squeeze

 

[Web Monkey]

Originally was trained to control buoyancy by inflating dry suit. Having now moved to Florida and started cave diving, I am now in the habit of only inflating the dry suit enough to prevent squeeze. Everything else to controlled using the buoyancy compensator.

What are your views on this?

I add just enough air to the drysuit to keep it from crushing me.

The drysuit is for keeping dry, the underwear is for keeping warm and the BC for buoyancy.

Aside from anything else, air I put in my BC stays there, and doesn't vent itself off as I tilt one way or the other or change depth.

I believe that the various agencies teach using the drysuit for buoyancy because they think (probably rightly so) that the new OWD students are already overloaded with tasks.

Terry

 

[Dryglove]

http://www.baue.org/faq/dynamic_instability.html

Straight from the horses mouth(George Irvine)
http://www.baue.org/library/irvine_baue_talk.html#Weighting
"One big thing, and I know you guys all know this, is the way we do the weighting. The buoyancy compensator is a fine tuning device. It's not like a lifejacket or anything like that. There's no such thing as redundant buoyancy or backup buoyancy or backup any of this stuff. The drysuit is not an inflation device, it's not a backup anything. Drysuit is to keep you warm."

 

[Snowbear]

I believe that the various agencies teach using the drysuit for buoyancy because they think (probably rightly so) that the new OWD students are already overloaded with tasks.

The shop I occasionally DM for teaches OW students that the DS is for exposure protection and the wing (yes they teach OW students in a BP!!) is for buoyancy control.

 

[Jim Baldwin]

Originally was trained to control buoyancy by inflating dry suit. Having now moved to Florida and started cave diving, I am now in the habit of only inflating the dry suit enough to prevent squeeze. Everything else to controlled using the buoyancy compensator.

What are your views on this?

I know that PADI teaches to use the drysuit for buoyancy. I think that this is to help cut down on task loading with a new diver.

When I started using my drysuit I tried the drysuit as buoyancy method but it was uncomfortable so I went with the idea of adding just enough air to prevent a squeeze and using my BP/W for my buoyancy control because it was so much simplier to do.

Working with Open Water, Advanced and Rescue students who have little experience with drysuits I show them how it works. They're always amazed that I stay dry and warm after a day of diving. I don't get bogged down on this is the only way to make this work.

I try and go over in detail with the advanced and rescue students how the suit works and the advantages and disadvantages of each method and let them make their own decision.

Jim
Louisiana

 

[jerrynuss]

Using the drysuit for bouyancy in ow has nothing to do with experience. The idea is the diver is using a standard equipment configuration and not extremely negative equipment like a set of doubles. Some divers may require the addition of weight to get down ina drysuit. If this is the case the diver would weigt themselves to be just slightly negative at the beginning of a dive to compensate for the loss of weight due to gas being consumed. Since the drysuit is variable volume the diver adds just enough gas to keep the suit from squeezing or maintaining a relative constant volume. It he diver is weighted to be neutral or just slightly negative bouyancy will be maintained.

The BC was created to adjust for the loss of bouyancy due to wetsuit compression and loss of volume. So adding air to the drysuit is correct for maintaining bouyancy if the equipment is not heavy and the suit can support the weight without having large masses of shifting gas.

For diving in a set of steel doubles a bc is needed because of the greater negative weight. The diver will need to add gas to the drysuit to maintain from being squeezed. The bc will need to be used for flotation at the surface and bouyancy underwater. Because caves are not all at one depth addition to the drysuit and bc will be needed to adjust for increases in depth and venting to adjust for loss of depth.

The deeper the area the less change needs to be made, Boyle's Law.

The trick in cave diving is watch where a person is going and make adjusts ahead of time and not when the depth change has been made. After a few dives it is rather simple.

 

[detroit diver]

...........

The BC was created to adjust for the loss of bouyancy due to wetsuit compression and loss of volume. So adding air to the drysuit is correct for maintaining bouyancy if the equipment is not heavy and the suit can support the weight without having large masses of shifting gas.
..........

As this is a DIR forum, I'm going to call BS on this. It's just plain wrong. The drysuit is NEVER used for maintaining bouyancy. Period.