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Freedivers safety vest in development
- Thread starterHuan
- Start date
Thread Status: Hello
, There was no answer in this thread for more than 60 days.
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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
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
Definitely great device, and hope that it will be available soon. Thanks for your hard work on it! However I had similar thoughts like Sebastien:
Besides the SWB due to abrupt PaO2 pressure gradient, it could also cause DCS due to the uncontrolled ascent. Well, suffering SWB or DCS and getting to the surface is still better than dying at the depth, but I guess this might be also a legal responsibility concern.
The diver doesn't choose to deploy the unit- it deploys automatically when selected depth or time limits are exceeded.
I was not aware that faster ascent rates could cause blackout. But even if its true, I would prefer to be blacked out on the surface with my head supported face up rather than black out at depth and sink to the bottom.
It occurs to me that the pure freediving community and the spearfishing community may have different frames of reference and a different attitude toward the usefulness of this vest. While I have no experience with competitive freediving, it is my impression that competitors have all kinds of backup and few fatalities, Pipin's wife notwithstanding.
But freedive spearfishermen do not have all that backup, and fatalities are relatively frequent. We had a couple here in Southern California just this summer, and I lost a good friend several years ago. In the case of my friend, and in other fatalities for which I have any information, I think it is likely that this device could have saved lives, assuming that it works as advertised.
Perhaps it would be useful for me to describe the situation in which I would most likely benefit from this vest. In Southern California kelp beds, white sea bass are often in the upper part of the water column, perhaps at 25 feet or less. But after we shoot them, they often wrap up in the kelp on the bottom, and that might be at 80 feet or more. The most dangerous thing I do is dive down there and try to cut fish out of the kelp. I am way past my neutral depth and am very heavy, the vis is often poor, and I have kelp and mono shooting line all around me. When faced with a situation like this, I call for a friend to come watch me. But most of the time, the friend can't even see me after I descend through the kelp, and it would be very difficult for him to help. I know that many times when I am the one on the surface, I will get concerned that the diver has been down too long and will be on the verge of a dive, only to notice that he is on the surface nearby. I didn't even see him come up, so how much help would I have been able to provide?
In a situation like this when I am pushing depth and time limits, I would like to have one of these vests.
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Bill, I definitely agree that the device can help saving lives. What Sebastian wrote was as he called it "devil's advocacy" - just trying to point out some problematic spots that possibly still can be handled either through technical modifications, or at least through detailed instructions and warnings in the user manual.
The problem is that the device can cause harm or even kill you when it misfires and you suffer SWB or DCS because of it, although you would be perfectly safe without it in the specific dive. The misfiring can happen due to technical failure, user error (time/depth set too low), or simply because you go over the preset limits without noticing it because you are in good form and still well within your safety margin. However, I guess there will be a release valve (either automatic or manual) that you can use to reduce the ascent speed even when the vest misfires by surprise. You just need to be well informed and trained to use it properly.
The problem is that the device can cause harm or even kill you when it misfires and you suffer SWB or DCS because of it, although you would be perfectly safe without it in the specific dive. The misfiring can happen due to technical failure, user error (time/depth set too low), or simply because you go over the preset limits without noticing it because you are in good form and still well within your safety margin. However, I guess there will be a release valve (either automatic or manual) that you can use to reduce the ascent speed even when the vest misfires by surprise. You just need to be well informed and trained to use it properly.
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I'm sure there'll be a very carefully thought out booklet of disclaimers with this thing - making it clear that it's not a license to go gonzo. In reality though - most deployments are apt to be toward the end of a dive - and shallow.
Sebastian - your work in freediving is awesome!!! It's like a whole new esoteric current.
Sebastian - your work in freediving is awesome!!! It's like a whole new esoteric current.
Please excuse my ignorance, I haven't had time to see the specs. for this device, so am unware of whether it does have a 'dump.' Though I'm not liabelous type, I'd have to agree that the issue of DCS might also be a problem from an insurance point of view, and it would be sad to see this product come of the market or stopped in its tracks because someone threw a spanner in the works. Other than that I'm a backer.
Good one!
Seb
Mallorca, Spain
ww.sub7seas.com
Good one!
Seb
Mallorca, Spain
ww.sub7seas.com
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.
And again, if forced to make a choice, I'd rather be bent on the surface than blacked out on the bottom.
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.
BTW, this new vest is much better thought out than the DSA ever were, and I'm not talking about the electronics.
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.
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.
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.:head
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
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.:head
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
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
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
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
The thought on switching out a bottle would be to increase it's operating depth for freediving- not scuba.
Jon
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
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
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
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.
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.
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
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