StuartP wrote:
Yes that does look good. Price is around $3000 from the website!!

Was working on a (eerily) similar design in 2000, but shelved the project after it became apparent that it would be way too expensive to produce and keep it affordable for most freedivers. Good Luck Terry. (sure he'll get a bunch of sales worldwide, but if WE can't afford it, what's the use?)

There is scope for a smaller device that deploys automatically but if it only pulls you to the surface without keeping our head out of the water it will be mostly useless. (Even with a bright SMB )

Best still is to estimate your limits (I don't believe that you can know your limits until you have crossed the threshold), BUDDY UP and don't push yourself in an uncontrolled unsupervised environment. (also no point in being supervised by someone who doesn't know how to react when something does go wrong. A person prone to panic is also of no use no matter how long they have been qualified as a "rescue diver") Case in point - Morkel Swart drowning from a SWB in a Nelspruit pool with friends "watching" him while pushing himself for statics. RIP Morkie San.

If you can't watch your buddy surfacing from where you are floating at the surface, you are too far apart. (This is a hassle for most, I know, and ignored in a competiiton)

Have to agree on the young guns being he biggest danger to themselves. "You get bold divers and you get old divers, but NO old & bold divers" From a cheesy t shirt at sodwana years ago.

Maybe more of a question than a comment:
Lets say you are coming up after a dive where you over stayed you limit and deploy these inflatable devices to help you reach the surface. Won't this extremely fast ascent rather cause the blackout than help preventing it? And by ascending too fast, isn't there other dangers coming into play?

From what I understand a blackout is cause by the rapid change in pressure inside the lungs and the gasses trying to get in balance. Now with a rapid ascent the partial pressures of the gasses have less time to balance out and you will blackout.

In other words: these devices must only be used(according to me) if you are already blacked out, but then you are not able to activate it. So what is the use.

Best is to stay in your limits and have someone to watch you.

As far as i understand ( from diving nitrox) a Swb is caused by a drop in partial pressure of o2' your brain needs a certain pressure of oxygen to operate. So when surfacing from 20 upto 10 metres the partial pressure halves, from 10 to te surface it halves again. So if you are feeling ok at 20 you may already be in trouble, if you are ( physically) feeling signs of lack of 02 at 20 like a contraction you are most probably screwed.

Our device worked on the premise of a timed alarm connected to a depth gauge. You would set a max dive time ( similar to declaring a target time or depth) and once the time is exceeded our device would inflate automatically - not for use in overhead environments - no chance of altering or resetting the device until you reach the surface on your return.

Once a swb occurs you want to get to the surface asap. So the speed at which you ascend becomes irrelevant, as long as it is quick.

Hi guys,

Reading some of the posts I see some misconceptions about what a SWB is and how they happen.

There is a difference between a deep water Blackout and a SWB but the former applies mostly to freedivers.

Below is a link to an article I wrote about SWB's. It was published in USM and was moderated by Trevor Hutton and Terry Maas.

www.sealine.co.za/view_topic.php?id=46738&forum_id=68

hey chaps,
Definately a lot learnt from all the posts. Reading up on the causes and incidents of spearos suffering from swb's was a real eye opener. Knowledge that could really save your life. I think far to many divers seem to throw caution to the wind and do their own thing when boat diving instead of sticking to a real dive buddy system. As for the auto inflatable vests im sure the prices will decrease if more manufacturers join the market.
Safe diving everyone,
the garrick have hit the south coast,
time to dive

Hi guys,

I’ve read this thread a number of times and have been somewhat reluctant to contribute my 2 cents worth due to “Diver Safety” complexity. You can write a book on the subject. Diver Safety starts at Dive Planning stage which normally includes a Contingency Plan. I’m going to chat to Chris and see if we can start a “DIVER SAFETY” column in the USM so all can benefit from.

Diver safety is not all about SWB prevention, there are other factors which are detrimental to a diver such as cramps … ever suffered a serious calf muscle cramp? It’s so painful it’s debilitating.
Inflation vests … I haven’t seen the new designs but the old inflatable vests resembled the floatation vest used on boats except it had a timer which you could be set before a dive and reset it when you surfaced. The timer was attached to a mini cylinder with compressed air. Once the timer reached the preset time, the seal on the cylinder was ruptured and the vest would inflate thus brining a diver back to the surface. These vests weren’t very successful, especially among the spearos … could you imagine you have this beauty lined up and the timer activates the vest’s inflation just before you squeeze the speargun’s trigger … ( L.o.l.) I think the ocean would be polluted with one more foreign article.

Referring back to the thread, there is a comment which I want to compliment and that is “STEADY’s” contribution. If more freedivers / spearos practiced the One Up / One Down buddy system the way STEADY explained, there would be far less accidents. I’d like to add onto his comment. When your buddy has surfaced, look into his/her eyes for any signs of glazed stare, look at their body language, are they breathing funny, speaking in a strange way, shaking LMC (Loss of motor control). These are all signs of a Samba, beware of them, they can be very subtle or quite violent. In any case, allow at least for a 20 seconds period of observation before you dive. A diver can surface okay and can still suffer a blackout within the first 20 seconds of surfacing… be very careful of that too. If a Samba is observed or your buddy suffered a SWB, be anal and make sure he does not dive for the next 24hrs.

Keep well hydrated during your water session and make sure to replenish natural minerals and salts which are lost during a water session. Get enough rest the previous evening and dive well within your capacity, then you should have little chance of having an incident. Diver Safety should become a habit … a way of “Diving Life Style”

Safe diving everyone.