What are your thoughts about our constant buoyancy BCD ?

[eelnoraa]

From pure usage perspective, a BCD with constant buoyancy is easy. A BP without wing is a BC with constant buoyancy with contant buoyancy of -5lb for SS plate. A BC is there to make sure the entire diver+rig's buoyancy change can be compensated by changing the BC's own buoyancy.

 

[TMHeimer]

Someone invents this every few years, but it has never become popular (or gone into production, as far as I know).

Why would someone want one of these, instead of being properly weighted?

flots.

A lot of interesting questions, some complicated. I would assume the whole idea is based on properly weighted divers.

 

[dumpsterDiver]

Maybe you people are smarter than me, but I can see ZERO benefit from something like this. And the list of negatives is huge.

 

[garethingham]

The device uses a bladder that does not inflate at all until about 3 atm pressure. It's pressure volume characteristic is such that it changes only about 3 lb in buoyancy from 96 feet to the surface. Thus, it is essentially rigid with constant volume. In answer to your other question, the device will not compensate for changes in buoyancy due to wet suit compression. In actual diving with a 3 mm full suit we found that you can go from 40' to the surface without having to let out air.

---------- Post added August 14th, 2014 at 02:47 PM ----------

I hope this is not utter nonsense after 5 years of development and testing!

You may find it interesting to look at our web site Home where the technology is explained. The buoyancy change with this device during a recreational dive is small enough that the diver can control buoyancy by shifting the tidal volume. Air does not have to be put into the bladder or expelled from the bladder after an initial adjustment.
I think it is is especially useful for technical divers because they often carry equipment that varies in buoyancy, so it is not possible to know how to weight oneself precisely before getting in the water. Th constant buoyancy BCD solves this problem as it is essentially applying "negative weight" which does not vary with depth.

Not utter nonsense but still unnecessary. Pen vs pencil in space analogy.

If you are requiring a machine to control Archimedes for you them perhaps stay in the shallow end of the pool.

 

[NAM001]

I played with something like this as a means to provide a static lift as a means to minimize the air int he wing/bcd. I used it with my steel tanks which made me quite heavy depending on what wet suit i wore. Ultimately i got to where the only air i used was to comp for the weitht of air in the tank and suit compression. What i ended up with was pvc tubes with no air connectons. Each tube could lift 3# so with one on each side i got 6# lift when i did not wear the wet suit. Another configuration i tried was tu do the seme thing but allow it to be floodable as i used air. I abandoned that idea. Ther first concept worked well however. I used it again a few weeks ago when i was diving in my lavacore only and ended up too heavy with my lp120. What the heck someone played with some idea to get where we are today. One win out of a hundred failures is really not that bad of a success rate. One more thing, what i used was in addition to the bcd/wing. It was used as static lift like lead is used for static weight.

---------- Post added August 16th, 2014 at 04:19 AM ----------

I remember these form te 60's they were need however you still had the moving bubble and when you pointed down the air ran out and you got heavy.

Or maybe this one from 1968:

 

[Rich Keller]

The "gear solution for a skills problem" argument is BS. The BCD itself is a gear solution for a skills problem as is the dive computer and I rarely see anyone dive without both. Your system sounds like it might be an interesting innovation that could sell to new divers if it was marketed properly but I do not think too many experienced divers are going to buy this product. On the other hand the same things were said about BCDs and computers when they first came out and now most people can not dive without them. I do not know where you got the idea that commercial divers use BCDs, I never used one and never saw another commercial diver using one either. Stick to the newer sport divers with this product and push the hovering aspect, sport divers love to hover, it is the subject of an endless number of threads on SB.

 

[lmarks]

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.

---------- Post added August 16th, 2014 at 07:37 AM ----------

The benefits are that there can be be no runaway ascents or descents and, you can precisely compensate for overweighting and not have to change that compensation during the dive.

---------- Post added August 16th, 2014 at 07:39 AM ----------

Your comments are noted and appreciated.

---------- Post added August 16th, 2014 at 07:41 AM ----------

Actually the idea is based on overweighted divers. The device provides the equivalent of "negative weight" that compenstaes for the overweighting regardless of depth.

---------- Post added August 16th, 2014 at 07:44 AM ----------

The device you allude to is a rigid hollow cylinder that is partially filled with water. In that case, there is an air bubble that moves around. We use a high pressure bladder that has no water in it and thus no air bubble to move around. In fact one of the additional benefits is that you can deflate the bladder from any body position.

 

[cascas]

We have developed a BCD that does not change buoyancy with depth. This prevents runaway ascents and descents. With it you do not have to inflate and deflate the BCD during a dive. It allows the diver to precisely compensate for overweighting and the compensation is fixed regardless of depth. Details are at Home. We have not yet commercialized this technology and would like to get feedback from divers before doing so. Do you think this would be a useful feature ? Are there disadvantages we may not have thought of ?

As a technical diver I would never even think of using or even trying one. As a former scuba instructor I do not approve of these sort of automated devices. If a diver can't keep his or her buoyancy, he she should stay out of the water.

As a challenge to create such a device, nothing but kudos. But I would hate seeing them in shops.

 

[Bob DBF]

I wanted to address also the statement some have made about it being an equipment solution to a skill problem. I hate that phrase in general, because it is too often a glib dismissal of what can be a good idea. If you think about it, the existence of a BCD at all is an equipment solution to a skill problem, since we could do a dive with the tank under our arms. I wish that phrase would go away so that we can look at each innovation to see if the benefits it brings to a dive outweigh its negative characteristics.

RichKeller
The "gear solution for a skills problem" argument is BS. The BCD itself is a gear solution for a skills problem as is the dive computer and I rarely see anyone dive without both. Your system sounds like it might be an interesting innovation that could sell to new divers if it was marketed properly but I do not think too many experienced divers are going to buy this product. On the other hand the same things were said about BCDs and computers when they first came out and now most people can not dive without them. I do not know where you got the idea that commercial divers use BCDs, I never used one and never saw another commercial diver using one either. Stick to the newer sport divers with this product and push the hovering aspect, sport divers love to hover, it is the subject of an endless number of threads on SB.

Although the phrase "an equipment solution to a skill problem" may be used dismissively, and there are a lot of devices we use now that had that phrase used on them, there is little memory of devices that have not met acceptance such as other automatic / constant buoyancy devices mentioned in this discussion.

I like to look at the phrase, "an equipment solution to a skill problem", more as a shorthand for the proponent of any such labeled device to show me how useful the device will be to me and how it won't get me killed when TSHTF. I think the phrase is more a challenge for the proponent to show the device is effective and safe, which traditionally has been the bar. I believe the phrase is even more important than in previous decades, because of this cultures nature to embrace new technology without reservations, and the "professionalism" of advertising and sales in selling products, regardless of the need.

"An equipment solution to a skill problem" is more like an antidote for "it's a life support device".




Bob
-------------------------------

That's my point, people, by and large, are not taught that diving can be deadly, they are taught how safe it is, and they are not equipped with the skills, taught and trained to the level required to be useful in an emergency.

 

[captain]

I played with something like this as a means to provide a static lift as a means to minimize the air int he wing/bcd. I used it with my steel tanks which made me quite heavy depending on what wet suit i wore. Ultimately i got to where the only air i used was to comp for the weitht of air in the tank and suit compression. What i ended up with was pvc tubes with no air connectons. Each tube could lift 3# so with one on each side i got 6# lift when i did not wear the wet suit. Another configuration i tried was tu do the seme thing but allow it to be floodable as i used air. I abandoned that idea. Ther first concept worked well however. I used it again a few weeks ago when i was diving in my lavacore only and ended up too heavy with my lp120. What the heck someone played with some idea to get where we are today. One win out of a hundred failures is really not that bad of a success rate. One more thing, what i used was in addition to the bcd/wing. It was used as static lift like lead is used for static weight.

---------- Post added August 16th, 2014 at 04:19 AM ----------

I remember these form te 60's they were need however you still had the moving bubble and when you pointed down the air ran out and you got heavy.

That's a pretty old idea that was used by deep wreck divers using wet suits and steel doubles before modern dry suits and BCs. I believe Cousteau also used it in certain situations.