What are your thoughts about our constant buoyancy BCD ?

[DaleC]

Next question: Does your system auto deflate upon ascent, as it auto inflates upon descent? Or is the lack of runaway ascents solely dictated by the small displacement of the bladders.

 

[eelnoraa]

The volume is not fixed. It adjusted when the diver enters the water to provide neutral buoyancy. After that, there is little or no adjustment required despite changes in depth.

---------- Post added August 16th, 2014 at 07:35 AM ----------

To make it clearer - There is adjustable buoyancy, not fixed - but it does not have to be changed with changes in depth.

How exactly do you detect and decide whether the diver is positive or negative buoyant? What external signal or measure do you use to detemine this?

 

[lmarks]

Questions
1-Where is the air sourced from the the LP or HP regulator port and what pressure are the bladders operating at above ambient .
2-Is there any consideration for a stuck open inflater to prevent over inflation to the point of rupture such as on a BC.
3-If higher pressure is required to inflate that is more of a reduction of air available to the diver then with a regular BC that only requires air at ambient, how much would the reduction be.
4-What is the weight of it, is it more or less than a regular BC. When empty how negative is it.

1-Air is sourced from LP port
2-There is a relief valve that limits maximum pressure
3-You are correct - but the amount is negligable
4-It adds about 8 lbs of weight - I haven't actually measured it's negativity, but I will say that when I dive it, I use about 2 lbs less than usual

---------- Post added August 19th, 2014 at 05:23 AM ----------

I fully respect your point of view. But there are a surprisingly large number of uncontrolled ascent fatalities each year and this could possibly save some of those lives. Also, this would allow the technical diver to adjust for carrying additional unknown negative buoyancy such as new equipment. Now he/she may need to add a fair amount of air to a conventional BCD and that will need to be adjusted frequently with changes in depth.

Pretty soon divers won't have to know how to dive.

Just like cars, first there was the automatic transmission, then there is development with anti lock brakes, now we have self parking cars, self steering cars, automatic braking. Pretty soon people won't need to know how to drive, it will all be done for them. Pretty soon divers won't need to know how to dive, it will be done for them.
I like to dive because it's a hands on thinking sport, something that's still manual that I can do and get good at. Like working with wood or some other hands on hobby.
If the automatic trend keeps up pretty soon any blob would be able to strap on a tank and go under - propelled by automatic fins or scooter, controlled by an automatic BCD, can't run out of air because a sensor will force the diver to the surface when the air gets low, etc.

I choose to go the other way, towards minimalism....it's a new trend of an old school idea. Modernized, streamlined, making use out of all the great new "simple" gear available to us in this day and age.
The more I dive and learn the more gear I get rid of. I have it down to a bare minimum, just what I need for the dive at hand. Many times I don't even use a BC, and that's with a 7mm suit. If I had the luxury of living somewhere with warm water I would probably never use a BC.
Proper weighting, proper streamlining, keeping skills sharp, staying wet, that's where it's at, not some contrivance to top the "elevator lever".

---------- Post added August 19th, 2014 at 05:26 AM ----------

The diver determines if they are positive or negative and then adjusts the amount of air in the high pressure bladder. This is NOT an automatic servo-system.
It may best be described (as one of the commenters called it) as "variable static buoyancy."

How exactly do you detect and decide whether the diver is positive or negative buoyant? What external signal or measure do you use to determine this?

---------- Post added August 19th, 2014 at 05:34 AM ----------

I obviously need to do a better job explaining the device. It offers "variable static buoyancy" that is you actively set your buoyancy - positive, neutral, negative - your choice - and then it is fixed - you have to do little or no further adjustment during the rest of the dive. I hope this is a better explanation.

---------- Post added August 19th, 2014 at 05:40 AM ----------

That's a very novel concept. However it sounds like a gear solution to a skills problem. I'll give you guys props for ingenuity though.

Certainly a reasonable point of view. However, there are a significant number of deaths from uncontrolled ascents each year. It is our hope that this could eliminate some or most of these fatalities. Also, remember that when you change your buoyancy by using a different wetsuit or by carrying new equipment, you have to guess how much weight to put on. If you go in the water significantly negative, you will have to add a lot of air to your BCD. This large amount of air must constantly be adjusted with changes in depth. With our BCD, this is not a problem.

 

[captain]

1-Air is sourced from LP port
2-There is a relief valve that limits maximum pressure
3-You are correct - but the amount is negligable
4-It adds about 8 lbs of weight - I haven't actually measured it's negativity, but I will say that when I dive it, I use about 2 lbs less than usual

---------- Post added August 19th, 2014 at 05:23 AM ----------

I fully respect your point of view. But there are a surprisingly large number of uncontrolled ascent fatalities each year and this could possibly save some of those lives. Also, this would allow the technical diver to adjust for carrying additional unknown negative buoyancy such as new equipment. Now he/she may need to add a fair amount of air to a conventional BCD and that will need to be adjusted frequently with changes in depth.






---------- Post added August 19th, 2014 at 05:26 AM ----------

The diver determines if they are positive or negative and then adjusts the amount of air in the high pressure bladder. This is NOT an automatic servo-system.
It may best be described (as one of the commenters called it) as "variable static buoyancy."



---------- Post added August 19th, 2014 at 05:34 AM ----------

I obviously need to do a better job explaining the device. It offers "variable static buoyancy" that is you actively set your buoyancy - positive, neutral, negative - your choice - and then it is fixed - you have to do little or no further adjustment during the rest of the dive. I hope this is a better explanation.

---------- Post added August 19th, 2014 at 05:40 AM ----------



Certainly a reasonable point of view. However, there are a significant number of deaths from uncontrolled ascents each year. It is our hope that this could eliminate some or most of these fatalities. Also, remember that when you change your buoyancy by using a different wetsuit or by carrying new equipment, you have to guess how much weight to put on. If you go in the water significantly negative, you will have to add a lot of air to your BCD. This large amount of air must constantly be adjusted with changes in depth. With our BCD, this is not a problem.

And here in lies the crux of the problem, instruction that doesn't teach how to not be grossly overweighted. That and the use of different rental equipment never lets the diver be able to determine correct buoyancy. If you own your gear then it is possible to get the familiarity with it so that over weighting does not occur. I would bet that 98 percent of the uncontrolled accents are new divers using ill fitting rental gear that they are unfamiliar with.

 

[DaleC]

So anyways, about that photo...

 

[boulderjohn]

But there are a surprisingly large number of uncontrolled ascent fatalities each year and this could possibly save some of those lives.
...

Certainly a reasonable point of view. However, there are a significant number of deaths from uncontrolled ascents each year. It is our hope that this could eliminate some or most of these fatalities. Also, remember that when you change your buoyancy by using a different wetsuit or by carrying new equipment, you have to guess how much weight to put on. If you go in the water significantly negative, you will have to add a lot of air to your BCD. This large amount of air must constantly be adjusted with changes in depth. With our BCD, this is not a problem.

I challenged you on this earlier, and you ignored me.

I just went through every case study in the 2008 DAN report you cited in the safety section of your web site. Yes, there are quite a few fatalities related to rapid ascents in that study, but these are almost all intentional rapid ascents, chiefly because the diver was out of air. They are not the unintentional rapid ascents due to lack of buoyancy control that you are claiming. I found exactly two cases in which the diver MAY have ascended rapidly due to lack of buoyancy control. I say MAY because they did not have enough information in the case study to form a judgment.

In the fatalities that were ascribed to rapid ascent, the problem was air embolism from holding the breath during the intentional rapid ascent. Do you suppose that every diver who made a rapid ascent after an OOA emergency held the breath and died from an embolism? I don't. I suspect many times that number made a rapid ascent, exhaled as they were taught in in their instruction, and lived without any report being made anywhere. They were aided in their ascents by the expanding air in their BCDs, which will not happen if they are wearing your BCDs. In that case, with their delayed ability to reach the surface, they may be more likely to hold their breath an embolize.

So how many people could potentially be saved by your BCD, and how many would potentially be killed by it?

 

[Eric Sedletzky]

I challenged you on this earlier, and you ignored me.

I just went through every case study in the 2008 DAN report you cited in the safety section of your web site. Yes, there are quite a few fatalities related to rapid ascents in that study, but these are almost all intentional rapid ascents, chiefly because the diver was out of air. They are not the unintentional rapid ascents due to lack of buoyancy control that you are claiming. I found exactly two cases in which the diver MAY have ascended rapidly due to lack of buoyancy control. I say MAY because they did not have enough information in the case study to form a judgment.

In the fatalities that were ascribed to rapid ascent, the problem was air embolism from holding the breath during the intentional rapid ascent. Do you suppose that every diver who made a rapid ascent after an OOA emergency held the breath and died from an embolism? I don't. I suspect many times that number made a rapid ascent, exhaled as they were taught in in their instruction, and lived without any report being made anywhere. They were aided in their ascents by the expanding air in their BCDs, which will not happen if they are wearing your BCDs. In that case, with their delayed ability to reach the surface, they may be more likely to hold their breath an embolize.

So how many people could potentially be saved by your BCD, and how many would potentially be killed by it?

It still boils down to the fact that if divers did what they were trained to do in regular open water class none of this would be an issue and there would be no need for this device. Diving down and putting a few shots of air into a BC to stay neutral, then venting it accordingly for an ascent doesn't seem like brain surgery to me. I still don't see an excuse for running OOA, being overweighted, not knowing how to use a BCD, being too out of shape to dive, not knowing how to fin properly, etc, etc., and I really don't think it's in the best interest of diving to create yet another layer of equipment to deal with the shortcomings of some people who have horrendous skills.
It seems to me that deciding to become a better diver would be the better solution not another contrivance.

 

[Rich Keller]

I obviously need to do a better job explaining the device. It offers "variable static buoyancy" that is you actively set your buoyancy - positive, neutral, negative - your choice - and then it is fixed - you have to do little or no further adjustment during the rest of the dive. I hope this is a better explanation.

So you are really going back to what we used to do before BCDs were invented but automating it for the people who have no idea how it works. You get to the bottom then set the amount of buoyancy you want and take into consideration the difference between a full & empty tank. I used to find neutral at the surface with a full tank and then split that difference so I was a couple of pounds heavy at the start of the dive when I wanted to be on the bottom and a couple of pounds light at the end when I wanted to be on the surface. A couple of pounds either way is easy enough to adjust for by other means. You BCD does the same thing but the diver makes the adjustment at the bottom at the start of the dive regardless of how much they are over weighted. That means just a one time introduction of air into the device saving more air for the dive, the only way to save more air is if you can pre-fill it on the surface from another tank to a previously know amount. It is a simple concept but they have not taught that in OW classes in decades. Even when I try to explain this concept to experienced divers who should know better it is like I am speaking another language. You might have a shoot given that the changes in training have paved the way for you but you will need to do a MUCH better job of explaining this or it will never sell.

 

[cerich]

this would allow the technical diver to adjust for carrying additional unknown negative buoyancy such as new equipment. Now he/she may need to add a fair amount of air to a conventional BCD and that will need to be adjusted frequently with changes in depth.

I think we have a case of instead of just being an equipment solution to a skills problem, we have an equipment solution to a lack of understanding problem.

Not trying to just be a jerk but if a technical diver is doing what you wrote, they either haven't been trained or have been trained exceptionally poorly.

 

[scubafanatic]

It still boils down to the fact that if divers did what they were trained to do in regular open water class none of this would be an issue and there would be no need for this device. Diving down and putting a few shots of air into a BC to stay neutral, then venting it accordingly for an ascent doesn't seem like brain surgery to me. I still don't see an excuse for running OOA, being overweighted, not knowing how to use a BCD, being too out of shape to dive, not knowing how to fin properly, etc, etc., and I really don't think it's in the best interest of diving to create yet another layer of equipment to deal with the shortcomings of some people who have horrendous skills.
It seems to me that deciding to become a better diver would be the better solution not another contrivance.

...sounds like you have no plans to make your custom BP's compatible with this new system.

I agree with you about buoyancy control not exactly requiring MENSA membership, but perhaps I'm mistaken ?