Dry suit as BC backup

[ba_hiker]

During an advanced diving class (starts with advanced nitrox and goes through deco to "rec" mixed gasses) we were discussing a situation where a diver could not keep their bc hose connected and were unsuccessful at achieving positive buoyancy with just their dry suit.

They were wearing heavy doubles and had a single 40 cu ft stage. It was the start of the dive so all the tanks were full and weight was at the max. Their buddy and they finally fixed the prob, and they ascended normally. Here we kinda assume that a dry suit is a good form of alternate buoyancy. Is this really an alternative??

Of course they had several alternatives. The were at the start of the dive, with low nitrogen loading and no deco requirements, so a weight drop was an alternative (assuming they could free it from their crotch strap). Or they could have sent up a buoy an ascended the float line.

But we do really expect to be able to reach neutral buoyancy with just our dry suits. But does the neck seal release a bubble before this? Or does the gear restrict inflation to the point where this is impractical? Does anyone have any experience with this? Have you actually tried to maintain neutral buoyancy or achieve positive buoyancy with just the dry suit? Under what conditions? How heavy were you? What happens at the surface, is buoyancy adequate?

We are planning a series of experiments, but I though I would check experience and search the literature first

 

[CIBDiving]

Don't know what kind of suit you're used to but if I close the dump and fill it I have more lift than my 65 lb BC.

 

[waynne fowler]

During an advanced diving class (starts with advanced nitrox and goes through deco to "rec" mixed gasses) we were discussing a situation where a diver could not keep their bc hose connected and were unsuccessful at achieving positive buoyancy with just their dry suit.

They were wearing heavy doubles and had a single 40 cu ft stage. It was the start of the dive so all the tanks were full and weight was at the max. Their buddy and they finally fixed the prob, and they ascended normally. Here we kinda assume that a dry suit is a good form of alternate buoyancy. Is this really an alternative??

Of course they had several alternatives. The were at the start of the dive, with low nitrogen loading and no deco requirements, so a weight drop was an alternative (assuming they could free it from their crotch strap). Or they could have sent up a buoy an ascended the float line.

But we do really expect to be able to reach neutral buoyancy with just our dry suits. But does the neck seal release a bubble before this? Or does the gear restrict inflation to the point where this is impractical? Does anyone have any experience with this? Have you actually tried to maintain neutral buoyancy or achieve positive buoyancy with just the dry suit? Under what conditions? How heavy were you? What happens at the surface, is buoyancy adequate?

We are planning a series of experiments, but I though I would check experience and search the literature first

If someone can't get neutral with their equipment at the beginning of a dive by using the drysuit then they need to go back to school and start all over again cuz things are way WAY wacked out!.
Aside from that.
A bag shoot and ascent would be in order.

Edited to add..
Do a search on balanced rigs this should give you some real good insight as to how to go about what you are thinking of doing.

 

[gcbryan]

They should be able to use the suit, they should be able to manually inflate their BC, they should be able to swim their weight up, shoot a bag, have help from their buddy, etc.

 

[cummings66]

I agree with the thought that something was out of kilter on the setup they dove. It should have worked unless they were way out of line weight wise.