automatic vent valve for bc or wing?

[formula1mb@aol.com]

I've been looking into drysuits recently and thinking of buying my first but when I was looking at the features, I noticed almost all have the automatic vent valve on the shoulder to maintain a constant volume of air in the suit.

Afterward, I started wondering why don't any bc's have automatic, adjustable vent valves to maintain a constant volume of air? Sure they have the overpressure valves but why not an adjustable vent valve too?

Not only would it make it easier to maintain buoyancy and reduce the amount of fine tuning needed when changing depths, but it could be a great safety tool too esp for newer inexperienced divers. In an emergency ascent than, you can still vent manually but at least the bc would more or less take care of the majority of the venting and eliminate the risk of a completely out of control rocket ride to the surface.

Plus for a diver rescue, the task loading would be reduced since most of the venting would be automatic.

Am I missing something or isn't it a good idea? Of course you would still have the manual inflator for fine-tuning and emergencies but curious to see if it has been tried and if not, why not?

Robert

 

[redacted]

One reason is because a constant volume of air is not the solution to correct buoyancy.

 

[formula1mb@aol.com]

Yes I realize that but wouldn't it reduce the need to fine tune your buoyancy? I'm not saying it's a replacement for proper buoyancy skills but simply a way to make it easier.

Plus for emergency ascents or rescues, it would reduce the task loading and also reduce the chances of an out of control ascent.

 

[formula1mb@aol.com]

If you ever read on the bsac forum and other places, a lot of drysuit divers already do that and use the drysuit only for buoyancy control----letting the vent valve maintain a more or less constant volume and using the wing for backup.

 

[Peter_C]

If you ever read on the bsac forum and other places, a lot of drysuit divers already do that and use the drysuit only for buoyancy control----letting the vent valve maintain a more or less constant volume and using the wing for backup.

Most experienced drysuit divers use the gas in the drysuit to only remove squeeze (Also keeps loft in the undergarments for warmth) and the wing to control buoyancy.

I want my wing to only vent when I pull the dump valve or push the button.

 

[spectrum]

First of all the DS valve is a one way street. It does nothing to compensate for compression as you go down. That would require a lot more complexity.

I can see your point of preventing runaway ascents with new divers but IMO that is what training and shallow novice dives are for.

I and others before me have toyed with the concept of automatic control but it would need a lot of inputs including the compression response curves of compressible items such as neoprene gear and a signal to permit / halt a depth change. The system would also need to be position independent so it could shift on demand.

Pete

 

[formula1mb@aol.com]

First of all the DS valve is a one way street. It does nothing to compensate for compression as you go down. That would require a lot more complexity.


Pete

Good point and I wasn't referring to a valve that would compensate for both descending and ascending but only for ascending like a DS valve. You still need to add air when you're descending to establish neutral buoyancy at the deepest part of the dive but than when you start ascending the valve would start to vent. That way you only need to add air at the beginning of the dive apart from fine-tuning and when you start ascending the valve would handle the bulk of it. At least it would greatly reduce the serious possibility of an out of control ascent during any type of rescue, OOA situation, etc.

 

[halocline]

I am of the mindset that BCs in particular need to move in the direction of simplicity and minimalism, not added complexity and automation.

Even though your valve idea might lessen runaway ascents, I don't think it would eliminate them, and if a student diver became a little dependent on it and it stuck, that could be pretty problematic. Another safety issue with BCDs is establishing positive buoyancy at the surface; you could still do this but it would complicate it a bit. Unfortunately that added task loading would happen at exactly the time most new divers are at risk; on the surface.

 

[formula1mb@aol.com]

You dump the weights at the surface, per most standard rescue classes. I don't see it as being that much more complicated, you can replace the standard overpressure valve with an adjustable vent valve.

Drysuits already use them, not like it's a new unknown technology.

 

[formula1mb@aol.com]

Plus I'm not saying get rid of the standard inflator, that would still be there for fine-tuning, adding air, manual inflation, etc.