Freedivers safety vest in development

[Bill McIntyre]

You folks that are concerned about DCS are a lot better divers than I am. I know thats possible to get bent while freediving, but I don't think its a realistic concern for the great majority of spearfishermen.

And again, if forced to make a choice, I'd rather be bent on the surface than blacked out on the bottom.

[Ted Budion]

Seb is right. This happened to the first effort in this field, the DSA vest by Mares, 30 years ago. I agree that times have changed and so has microcircuitry. But litigation has grown worse. But I presume Chip has a keen eye on this as he has for WSB. Not to mention Terry, of course, being a surgeon he knows those legal risks too well.

BTW, this new vest is much better thought out than the DSA ever were, and I'm not talking about the electronics.

[Seacidal]

I'll try to address a number of concerns/questions that have been presented today. But first, I would like to point out that the device design is still being refined. I imagine a number of amendments and revisions will take place as testing proceeds.

With respect to a dump, or overpressure, valve. The device is anticipated to have at least one pressure release valve, in order to prevent bursting of the inflation bladder. It may be possible, though likely not recommended, to manually dump air during ascent. But bear in mind that such actions could prevent the diver from gaining buoyancy from the device.

Unlike a large scuba tank, the inflation tank is intended for a single use before requiring refilling. If a diver wishes for a device as was expressed earlier, perhaps they should consider the freedivers Ascent BC Belt (from Zeagle, I believe).

Regarding the risk of blackout during ascent, I believe the more commonly held view is that it is better to be safe than sorry. If a diver's blackout is precipitated by an increased ascent rate, then there is likely a strong chance that the diver would've blacked out or samba'ed. The device and its logic are designed to require a diver be sufficiently cognizant and oriented at the surface. If not, the device will inflate in order to ensure the diver's safety.

Regarding any risk of DCS. DCS is quite uncommon among freedivers. It requires significant skill and effort to become a real concern. I am not aware of freedivers adhering to the "no greater than 1 foot per second" ascent rule that is commonly employed to reduce the risk of DCS. If a diver blacks out at depth, or exceeds the limits which they themselves programed into the unit to ensure their own safety, then automatic inflation and the attendant return to the surface is intended.

Consultation with dive medicine experts is ongoing, and all discussions to date have indicated that the benefits provided by the present device far outweigh the minimal-to-negligible risks that might occur.

With respect to a maximum depth. The maximum effective depth of the unit depends upon a number of variables, including inflation source volume, inflatable bladder volume, diver weight and fat percentage, wetsuit buoyancy at depth, amount of weight carried by the diver, etc. Taking all of these into consideration, some targets were established for the device's performance. An initial target was to enable the successful retrieval of a 220+ lbs. "California" diver wearing appropriate wetsuit and weights from a depth of 120+ FSW. Obviously, a diver weighing less than 220 lbs, and with different gear, would have a different maximum depth of retrieval for the same volume of inflation.

As prototypes are refined and improved, actual performance may vary. It would not be too difficult for greater depths to be enabled through the use of different components.

I hope that I have answered some of the questions that have been presented. (without boring you) We're trying to provide as much information as possible, yet at the same time, to progress with the development of the finished product.

Thank you for all your interest and support.

Chip Bissell
Advisory Boardmember
Oceanic Safety Systems Inc.

[Jon]

Chip,

Do you have a volume for the bottles to be used yet? Could they be switched out with something larger easily, or is it a specialized valve/thread design that won't work with many different types of bottles?

I wouldn't be to worked up over lawsuits by divers who get DCS from having their butt saved by this device. Divers do get bent all th time even when they stay within their limits.

I had to rescue a scuba diver in the middle of Freedive-a-palooza a couple years ago- not part of our group- and I don't remember hearing about any lawsuits because they got bent due to uncontrolled ascent from using a new drysuit. I've also had to jump in and pull up a diver on other boat who was bent so bad he couldn't climb up his own boat ladder. When I got him out of his gear, and on 02, he couldn't believe he was bent because he was in the 'clear' on his computer and the other three divers who were with him weren't bent. it actually took me 20 mintues to convinve him that he did indeed NEED to go to the chamber.

DCS has many causes and to block a great product, like this, from market over some percieved risk would bock all development- and we're not even talking about something as advanced as a rebreather which have had multiple deaths on them over the past few years!

Speaking of rebreathers, maybe this thing should have a giant legal waiver engraved into the side of it- like the KISS rebreather does.

Jon

[Seacidal]

Jon,

It is important to keep in mind that this product is designed solely for freedivers. It is not to be used by scuba divers in any instance.

While the size of the inflation tank has not necessarily been finalized, we are considering the possibility of making different sized tanks available. It would not be as simple as swapping the tank to gain inflation volume. The tank volume is incorporated into the logic and software of the device, and would likely also require modification. Again, this has not been finalized.

Thanks for your interest, questions, and suggestions.
Chip

[Jon]

I understand it's only for freediving, but was trying to draw a corelation between liabilty on scuba and freediving equipment. It shouldn't be any greater for freediving equipment than it already is on dive computers or rebreathers.

The thought on switching out a bottle would be to increase it's operating depth for freediving- not scuba.

Jon

[Seacidal]

Originally Posted by sebastien murat

Hi,

A great safety device, but if I may play Devil's advocate:

My own research has shown that an excessive ascent rate (even without swiming) can itself be the cause of hypoxia of ascent, is/will there be a 'dump' on the unit, or is thre an uncontrolled ascent? In other words, though a diver at depth may feel having over-stepped his O2 reserve margin and deploy the unit in the hope of avoiding SWB, the unit may, if he is ascended excessively fast, precipitate a blackout.


Sebastien Murat
Sub7Seas Freediving

Hello Sebastien,

I would be very interested in learning more about your research, as the development team wishes to consider all instances of blackout, in order to consider how best they may be addressed.

If it's not too much trouble, would you please provide me with citations to journals or other documents that have published your findings. Peer reviewed publications would be preferable.

I am willing to pay reasonable reproduction and/or shipping costs.

You may PM or email me with additional information. Thank you.

Chip Bissell
Advisory Boardmember
Oceanic Safety Systems Inc.
LegalDiver@SBCglobal.net

[Marwan]

Chip,
i think youre doing a great job, obviously im not the technical expert compared to sebastien and some of the other members here, but from a practicality/commercial point of view, i would recommend that you have maybe several versions of the vest depending on activity. Clearly spearfishermen's requirements would differ greatly from say, a no limits freediver...so rather than attempt a one solution fits all, maybe address separate needs by separate models, it could also have a positive impact on your end price...
just my 2 cents
cheers

[DeepThought]

A few questions/suggestions (that I think were brought up on this thread before).

1) Once the warning starts is there anything the diver can do to prevent/delay the vest from inflating? If for example the diver is just on his way out from inside a cave/wreck or trying to untangle/cut his foot from a line (or trying to rescue a vestless buddy or any other unusual emergency).

2) I assume there's an emergency inflate button?

3) How similar is the device to a freediving computer? Is it in theory possible to add certain dive profiles that would trigger the vest? Let's say one dives to 120ft, ascend to 50ft, blacks out and starts to sink while there are still 30 seconds on the timer. In this case the vest could inflate when the diver already has water in his lungs.

4) Most blackouts/LMC seem to happen when the diver is already bouyant/has reached the surface. How about an optional "end of dive" button that would have to be pressed till X seconds after the end of each dive? So in theory if one reached the surface and blackedout, X seconds later the vest would inflate and make sure the diver's face are out of the water (assuming the vest ensures that when inflated on the surface).

5) Have you considered making the vest's gadget a full-feature freediving computer that can be seperated from the vest? I think that might increase the market potential. Or maybe making it possible to be triggered by some other programmable diving computer (such as the F1) so people could customize their own profiles.

Good luck with the project.

[Seacidal]

To address your questions:

1. Once the warning starts, (at present) to prevent inflation the diver must:
(a) return to the surface (in the event the warning was due to approaching the preset time trigger); or
(b) return to a shallower depth (in the event the warning was due to approaching the preset depth trigger).
This is deliberate, as a diver in these circumstances diver is likely cognitively impaired to some extent, and cannot be trusted to exercise consistently reasonable judgment.

2. Most likely, the device will provide a means for initiating emergency inflation. However, it will be such that accidental activation will be a virtual impossibility.

3. The initial iteration of the device will be directed toward recreational freedivers/spearfishermen. Additional versions, specially adapted for pure freediving, are likely to follow shortly. These would differ primarily in the definition of inflation activation conditions and available inflation volume.

4. Conditions to address surface blackouts have been incorporated into the device.

5. To your first question, Yes. As to your suggestion regarding triggering by another device -- extensive efforts has been made to preclude such interaction. Each unit has a unique transmission identity, which is registered through a "handshake" procedure, in order to prevent two divers' units from miscommunication with eachother.

Also, let me clear up a common misperception many seem to have about the device. The wrist unit does not trigger inflation of the device. If it did, and you happened to drop the wrist unit overboard while you were on a boat, it would inflate when the wrist unit reached a triggering depth or time. Such is not the case.

Thanks for your interest and support,
Chip Bissell

[azapa]

Hi, I have cross-posted this on another board as well to see if we can generate some more ideas.
This is a great project. Congrats to all involved. I am a freediver (intermediate level at best) and engineer (a good one, IMHO

I have been dreaming up a vest for some time, but I see you have got it to a very high state of development already. Let me give you my ideas, as compared to your version, they were very simple and a little "out of the box". I hope they help:

1. "my" vest would be very simple and low tech/ low cost to encourage more people to really use them. Freediving is an inherently low cost sport, and attractive for that reason.

2. I recognize (I do it myself nearly all the time) that many people freedive alone. I am careful, but know the risks. I could die any time I go out. I take the risk. Its either that, or not go out. I therefore need a chance to survive a BO.

3. The activation device would be hand held, passing out, releasing the squeeze, would inflate. It would work as follows: commence dive, once down (personal taste/ comfort point) arm with one hard squeeze. Retain with soft squeeze. I have ideas for "squeezer" to go down divers arm, inside wetsuit, appearing at wrist and fitting over glove. Low profile, lo drag, and snag proof. These may have to be duplicated, one on both hands working together.

4. I am not a doctor, but blackouts generally release muscle tension. Releasing squeeze starts inflation process. Connection squeezer>valve via mechanical connection, like bike brakes: steel wire within flexible steel tube guide.

5. Your inflation layout looks perfect.

6. On surface, a loud whistle blows, powered by same air residual from inflation process. In fact, whistle starts as soon as vest is filled. Both are on same manifold. Whistle has three points:
i. Attract attention of potential helpers
ii. alerts dopey diver himself
iii. angled so as to blow air (whistle) on divers face. This has been shown to be a very effective as a stimulus to bring around a blacked out diver

7. < US$100 target.

Of all the points, I think that 6 and 7 are important. OK, so its never going to approach the effectivty of your vest. But over a 10year period, may save the same quantity of lives?

You may consider the two price range models?


Please let me know if you need anything. Although, I have nothing more to offer other than these ideas!

If you need and "beta testers" in the cold, kelpy waters of Chile, let mw know!

GOOD LUCK........

[Seacidal]

Azapa,
I can tell you have thought long and hard about this, and you are to be commended for your efforts. They say that great minds think alike. That may be true. The features you refer to in your paragraphs 3 & 4 have been incorporated into a number of previous attempts and patents. The features in paragraph 6 would be more difficult to enable. However, additional surface signaling features have been considered and may be incorporated. Your paragraph 7 sets out one factor in determining how many, and what, additional features to include. Clearly, the primary objective of the device is to make every effort to help ensure the return of a unconscious freediver to the surface. To that end, performance and reliability are key, and cost is not controlling. Yet we recognize that in order for the device to be useful, it needs to be used. Therefore, it can't be priced out of reach. While pricing remains to be determined, I believe it will be as affordable as possible.

[azapa]

Hello Chip, thanks for your positive reply. I think I can see a nail being hit squarely on its head: are these going to be bought by solo freedivers?? If I had a buddy, why buy one?

This opens a whole "can o' worms" as some may say the product endorses or allow solo freedives.

For me, this is as a BIG point, as I actually like to solo freedive.

Secondarily, assuming the above, the alert system (signaling) is of paramount importance. I, personally, would have no use for the vest if it did not have it.

Best of luck, and congrats again on the initiative. I dearly hope it is a sucess.

..azapa....

[Seacidal]

While being returned to the surface in the event of blackout is obviously desirable, by no means is it a guarantee of survival. Subsequent surface rescue efforts may be required and are always recommended. Diving alone is risky, regardless. That risk may be reduced. But eliminated? Not likely. The present device may make the odds more favorable for freedivers, but survival is never a sure thing.

I don't know the usual conditions where you dive, but in many places (like California) the visibility and/or kelp coverage prevents you from observing your buddy throughout their dive. It is not uncommon to be diving to 30 feet, over a 50 foot deep bottom, with visibility of less than 15 feet. Say that your buddy makes a dive, disappears from view, and reappears on the surface some 100 feet away. If your buddy didn't return to the surface, when, and how, would you begin your search?

With an alert system as you suggested, you would have to ensure a reserve (or other source) of compressed gas to activate a whistle. And an audible alarm would have to either be audible underwater for great distance, or be of sufficient duration on the surface to provide time for your buddy to resurface from their dive.

As you can well appreciate, simple ideas often require sophisticated solutions in order to provide the desired function in ways which are effective, dependable, durable, and inexpensive. I welcome your suggestions and discussion of the features, and I encourage all of you to follow along as the development of this device proceeds toward becoming readily available.

Chip

[Fondueset]

I agree re- the buddy scenario. This device would certainly not be replaced by a buddy or be a replacement for one. I like the alarm idea but would not use compressed gas to power it. An audible alarm would be more economically and ergonomically handled with a battery operated device - a small strobe would be a great addition - there are quite a few on the market that are very small. A simple idea I had awhile ago was to attach a strobe to your float - assuming that you are attached to the float - with a timer that you have to deactivate upon surfacing. Primitive and I know being attatched to your float is not allways practical.

In short, I think an audible and visible alarm is a great idea. It could be marketed as an addon if you are trying to keep the base price down. It could probably be triggered in a couple of different ways - either off the guage/timer - or right off inflation.