Equipment Trends: The BCD

[danvolker]

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God, I hated those things!!!
Probably total number of dives with one for me was less than 5....they destroyed my underwater Zen

 

[AdivingBel]

Cave Adventurers in Mariana, FL offers a replacement for crotch straps that splits below the scooter ring and goes to either side of the BCD in the back. It solves an obvious comfort issue for those being pulled by a scooter attached to the crotch strap D-ring.

Yeah, that's the downside of the saddle strap, no scooter ring. Not a problem for her, but it is a negative. I had one laying around so it was an easy fix. I like easy.

 

[boulderjohn]

link? Looked, and don't see it....

I didn't either. When I was there, we talked about alterations to my Hollis SMS 75, and that was suggested. I said OK and they put it on. Give them a call.

 

[Eric Sedletzky]

Why aren't they? My understanding is that this was the original purpose of the first BCs. To help divers establish buoyancy on the surface. The early BC were modified aviation life preservers (Mae Wests) so they would float an unconscious individual face-up. The horse collar BC's were an evolution of this design. A jacket BC also floats a diver face up only back mounted BCs don't. As Dan points out a skilled diver doesn't need a BC under water, however a tired diver on the surface with negative tanks does.

I realize that manufacturers do not want to say BCs are life preservers because then they would need to meet Coast Guard regulations which they probably couldn't do. It would also open them up to additional liability.

I am not trying to argue with you and I know you are not the first to say this. However, I don't think this was always the case.

The first surface floatation device (horse collar) wasn't actually a BC because it was only intended to be used in an emergency at the surface to float a diver face up by pulling a string/lever that released CO2. This was something that was adopted from the military (Navy).
Then by evolution that device (or similar) became more developed to be "user friendly" by recreational gear companies and began to be used underwater as a BC. Then someone eventually had the brilliant idea to move it to the back.
So, your question was were BC's first designed to float you on the surface, no not really because a BC is a buoyancy compensator (at depth). What you were refering to was a surface floatation safety device which was not used as a BC. Most divers of that period didn't use them because they just cluttered up their front side and got in the way.
Here's the thing, if I'm wearing any sort of neoprene at all, even a shorty, that would be enough to give me all the surface floatation I need.
The rest is all weighting math. For instance in warm water, I wouldn't be using a 6 lb plate with a steel tank and trying to counter it with a 3 mil shorty, it's not going to work. I would use a lightweight plate and an AL80 then add just enough weight (if needed) to be able to hold a stop at 15 feet with 300psi in the tank (at the end of the dive). Lets say I'm diving in 5 mil in semi cold water, then I could use the same lightweight plate and maybe use a steel tank and add just enough weight to balance it out. If I'm wearing a full hooded 7mm suit (at home) then I'm using a 5 lb plate, steel 120, and a small weightbelt to balance it out. The critical factor is being able to hold a stop at 15 feet with no air in my BC, that's the perfect weighting. With that, anybody should be able to float on the surface with no air in the BC meaning that theoretically you don't need it at the surface.
I did some fun pool work a while back doing some ditch and dons in the deep end of the pool. This is when I first got my double hose and was goofing around with it doing some excercises out of the instruction book "New Science of Skin and Scuba Diving" (1967 edition).
I was using a steel 72 with straps (no plate) and board shorts, that's it. I found that with nothing to inflate or nothing to squeeze I could stay at any depth just by breath control including surface, it'didn't matter, and that was fresh water. I concluded that I could easily do a dive in a warm ocean using the same gear and in board shorts. It wouldn't matter if I was on the surface or at 100 feet, buoyancy wouldn't change if there's nothing to make it change (air cell, neoprene, etc.).
Back in the day (way before I got into it) I was told by an instructor that he used to make the students swim laps with a steel 72 strapped to their backs just to get them to relax (and in shape) and make them realize that they can do it just as easy with as without.

I think it would be an intersting experiment to start a new diver off with a thorough skin/freediving education, then add a tank and teach them no BC diving and adding small amounts of weight only as needed. Then eventually adding a wing and buoyancy control. They would already have perfect buoyancy control and a firm knowledge of weighting...they would have to otherwise they wouldn't be able to dive at all, no BC and too much weight flat doesn't work. This would be the additive learning technique, and I think it is a much more solid way to learn because it's the baby step method where they grasp each concept as they go.
The way it is now, they load up the student with way to much crap and too much weight, then it's up to the student to try and figure out what they don't need and begin to shed gear. Most never do they just give up diving.

 

[MichigandiverJon]

I can think of two more cases where the diver drowned at surface, because they panicked and could not remember how to remove their integrated weight...
The big issue is panic though....there are some people that panic easily, with most others in a wide range....
The ones that panic easily, and badly, really can't be divers....I have seen people like this actually forget even how to swim, as the panic overtakes them--even dog paddling is too much--they just thrash.

Which is to say....if just mild panic, the thought is reduced but still possible....the weight belt is still simple and most buddies will know how to remove a weight belt from a buddy....where as you CAN NOT say that most buddies know how to get their buddy out of his/her integrated weights....some just don't make sense...add some fear and panic in the buddy scenario, and both can drown....

Personally I have NEVER used integrated weights...just don't like the idea of them. I had no interest when Carmichael created integrated weight pockets for Halcyon....I saw it as fluff for some dealers, but NOT as something we would ever push as a DIR "optimization"

On the other hand, my wife Sandra uses them sometimes, so obviously I am not trying to push my ideas on anyone....just offering

Then again, I use fins that create so much thrust, that I can carry a good sized anchor, when freediving ---with no BC, so any worry or panic is not feasible with the tiny amounts of weight involved with another diver or myself on scuba....
Which of course, brings me to why good fins and propulsive technique, is almost equally as important as is the choice of BC and Weights
Sadly, fins and propulsive techniques get very little instructional time.

Dan......slight digression, but to what fins are you referring? Which ones are you diving? Thanks.

 

[Bob DBF]

Why aren't they? My understanding is that this was the original purpose of the first BCs. To help divers establish buoyancy on the surface. The early BC were modified aviation life preservers (Mae Wests) so they would float an unconscious individual face-up. The horse collar BC's were an evolution of this design. A jacket BC also floats a diver face up only back mounted BCs don't. As Dan points out a skilled diver doesn't need a BC under water, however a tired diver on the surface with negative tanks does.

The Mae West, and production variations, was not meant to be a BC, it was used as a life preserver in case you had an issue on the surface, and the CO2 cartridges could come in handy since oral inflation was through a modified tire valve which was a b**ch when you were cold. Actually one would weight about neutral on the surface, and use lungs for compensation underwater since the tank selection (and size) was not as big as it is now. The need for a BC underwater came from the use of thermal protection which could vary the buoyancy more than the lungs could handle, add to that the development of doubles, triples, and larger tanks, the BC also evolved. And yes wings were developed back then but were small players as is the BP/W now.

Because you weighted about neutral on the surface, or positive if you weighted for a target depth, staying on the surface was not the problem it can be now. If you were tired or had a problem on the surface, you could add a bit of air orally or pop the CO2. The problem Dan pointed out about cartridge misfires usually happened because of no maintenance rather than a flaw in design, mine always worked fine.

I wasn't in on the design of the BC, but I used each as it came along. I completely agree with Eric that "I'm still a firm believer that the best way to teach somebody proper weighting and buoyancy control is to take away their BC. If a person can learn to fine tune their weighting and buoyancy without the use of a BC then they have truelly mastered the two". Freediving is one of the best intros to SCUBA one can get, as it can teach weighting and buoyancy before it gets mixes up with SCUBA gear. Relying on a BC can easily mask over weighting which can cause buoyancy and trim problems.


Bob

 

[danvolker]

Dan......slight digression, but to what fins are you referring? Which ones are you diving? Thanks.

Dive-R Freediving & Spearfishing Fins - Hybrid Composite Design

I use my blades with the riffe Silent Hunter open heel pocket...it is stiffer than full foot pockets, so it transfers power from the blade better than the full foot pockets ( which bend too much), and this allows use with a dry suit if I really have to wear one for deep thermoclines.

 

[BDSC]

If nothing else, Dan knows his fins!

 

[boulderjohn]

I didn't either. When I was there, we talked about alterations to my Hollis SMS 75, and that was suggested. I said OK and they put it on. Give them a call.

I just broke form and gave my post further thought.

Yes, they make the alteration to the crotch strap I described, but it is not a stock item. The crotch strap system on the SMS 75, which is a side mount system, is more complicated than a standard back plate crotch strap, and you can't just replace it with a different style. They had to cannibalize it to use the front part with the scooter D-ring, add the diverging straps, and make connection points to the BCD. They measured me to determine the length. So, now that I actually thought about it, it's not going to be something you can just slap on a back plate. A system of that design would not be at all hard to make, though, and I'm surprised it is not being made, now that I have finally thought about it.

 

[danvolker]

If nothing else, Dan knows his fins!

Thanks, I think


To me on a vacation, I would be willing to use junky rental regs or BC's if I had to, but I will ALWAYS be using my fins..either my Dive R's, or Extra Force ( if doing serious penetrations). To me, the fin choice is the MOST important gear choice, as the differences in performance are so much more extreme with fins. As to BC or wing, I don't even need one
As to reg, I still have a 15 year old scubapro Mark2 1st with R190 2nd stage....which I did many 300 foot deep dives with, even though this is the bottom of the barrel for Scubapro regs....My Mark25 AND g250'S THAT i USE NOW BREATH better, but the difference is something I really don't care much about...same with cheap Sherwoods or any other regs I have used. I could care less about what computer I use, and am as happy using a bottom timer and a depth guage. The fins ARE the defining gear for safety and for getting to places not possible with other gear.