Uncontrolled Ascent - Solution (?)

[ylange]

Dear all,

This question is mainly for dive professionals and scuba certification agencies.

With the goal of reducing injuries when divers (especially beginners) ascend too fast to the surface and hold their breath due to panic, I was thinking about designing a device which can automatically release air from the BCD at certain vertical speed and depth combinations, thus slowing down an uncontrolled rapid ascent.

My question is whether you feel that this solution poses more benefit (i.e. preventing uncontrolled rapid ascent) or more harm (i.e. slowing down an ascent and preventing divers from reaching the surface as fast as possible in an emergency)

Detailed answers will be highly appreciated.

 

[Thalassamania]

Divers ascending too fast to the surface and holding their breath whilst ascending are two separate problems. Ascending too fast with a high nitrogen load can cause DCS, ascending slowly whilst holding your breath will still result in an AGE.

Then there is the question of what is "too fast?" The agencies today (and the computer manufacturers) are pretty much at 30 fpm. But is this because 30 is a great number, or because back when divers were supposed to be coming up at 60FPM several studies indicated that most divers were coming up at 100 or even 120 FPM? I was taught to ascend 5 feet on my depth gauge and then 5 seconds on my watch, cross checking every 5 seconds and adjusting as I went. 60 fpm seemed a fine rate to me then, and as far as I could tell never created any problem since the tables I was using (USN) were designed with that rate in mind.

As far as I can tell divers surfacing too fast in a panic and holding their breath simply is not a significant enough problem to warrant a solution of this sort.

 

[ylange]

Dear all,

This question is mainly for dive professionals and scuba certification agencies.

With the goal of reducing injuries when divers (especially beginners) ascend too fast to the surface and hold their breath due to panic, I was thinking about designing a device which can automatically release air from the BCD at certain vertical speed and depth combinations, thus slowing down an uncontrolled rapid ascent.

My question is whether you feel that this solution poses more benefit (i.e. preventing uncontrolled rapid ascent) or more harm (i.e. slowing down an ascent and preventing divers from reaching the surface as fast as possible in an emergency)

Detailed answers will be highly appreciated.

 

[RJP]

Short of knowing HOW this device would work - is there any way to ensure that it is infallible - I would have to say it sounds like a bad idea.

Beyond the obvious fact that "the diver should be able to control how much air is in the BCD" from a skill standpoint I think that "ONLY the diver should be able to control how much air is in the BCD." Suppose this device "misreads" a situation and starts venting? Suppose it simply fails - either "open" or "closed"?

As always, a gear solution to a skill problem is just not a good idea.

 

[DanBMW]

Automatic Activation Devise - Sounds like what we use to try and prevent skydiving injuries. If you are falling too fast at a low altitude, your reserve automatically opens. I'm not sure if SCUBA divers would be willing to spend the $1,200 for a similar devise that slowed them down automatically if ascending to quickly. Seems sorta like a solution chasing a problem that is not really that bad of a problem!

 

[SteveAD]

There are not a tremendous number of injuries due to overinflated BCs that this device could have prevented. The majority of excessive ascent rates are due to the diver swimming to fast, or the diver simply laying on the power inflator.

As RJP said a hardware solution to a skill problem.

 

[TSandM]

I don't like the idea of an automatic device, but I have to say that buoyancy issues are related (according to the DAN reports) to a significant number of injuries. And my guess is that most of those are rapid ascents, initiated by some incident, stress or error, but perpetuated by expanding gas in the BC and/or drysuit. Having something automatically dump would possibly prevent some of those injuries, but I have problems seeing how it would know how MUCH to dump (making a panic-stricken, rapidly ascending diver into a rapidly descending diver is not an improvement) or WHERE to dump (unless the diver's in one of those 7 dump valve BCs).

 

[Jim Lapenta]

It's alot cheaper to train divers properly to vent and use buoyancy control. Those who refuse to learn or practice what they are taught soon get claimed by Darwin anyway. Solution for problem that could be easily remedied or eliminated by training and adhering to that training. Like putting an up and down lever on a bc- why? Other than to make money off of a gimmick from people who don't know better.

 

[keyshunter]

It's alot cheaper to train divers properly to vent and use buoyancy control. Those who refuse to learn or practice what they are taught soon get claimed by Darwin anyway. Solution for problem that could be easily remedied or eliminated by training and adhering to that training. Like putting an up and down lever on a bc- why? Other than to make money off of a gimmick from people who don't know better.

I wouldn't be too quick to criticize the up-down lever. It won't be long until Oceanic brings out it's dive computer controlled up-down system which will control not only your ascent/descent, but your buddy's as well.

 

[Jim Lapenta]

I'd be just as critical of that if not more so! Although it would be cool for those annoying instabuddies. Just hit a button and away they go!