Questions regarding backplate and doubles

[2airishuman]

Hello everyone

Yes, I'm new, please be kind.

In my reading, it seems to me that jacket style BCs offer few if any advantages to the diver, other than being less intimidating and offering marginally better trim at the surface. Are there reasons why I shouldn't start with a backplate and wing when I'm ready to move on from rental gear?

Similarly double tanks seem to have clear safety advantages and no disadvantages except cost. Plenty of personal accounts out there of freeflowing regulators, runaway BCs, and clogged dip tubes, all easier to handle with doubles.

What am I missing?

 

[cool_hardware52]

Hello everyone

Yes, I'm new, please be kind.

In my reading, it seems to me that jacket style BCs offer few if any advantages to the diver, other than being less intimidating and offering marginally better trim at the surface. Are there reasons why I shouldn't start with a backplate and wing when I'm ready to move on from rental gear?

Zero reason not to move to a BP&W. A BP&W is a highly adjustable, modular BC, it's not a Fighter Jet. You don't need to buy and replace 1/2 dozen jackets before your are "ready" for a BP&W.

Similarly double tanks seem to have clear safety advantages and no disadvantages except cost. Plenty of personal accounts out there of freeflowing regulators, runaway BCs, and clogged dip tubes, all easier to handle with doubles.

What am I missing?

Doubles are:

More expensive, 2 x tanks, bands, 2 x regs

Harder to rent

Heavy

Have enough gas to get you into trouble, and maybe not enough to get you out, get some gas planning education.

To benefit from the added "safety" manifolded, Isolated doubles offers required specific knowledge and considerable practice. Without this they only offer additional failure points. Do find qualified instruction, a frightening % of the diving business has no idea how a manifold actually works.

May be more expensive to fill, and the chances of the fill station screwing up is not zero, as many have no idea how an Iso manifold works.

Personally I prefer doubles, my "single rig" is doubled up LP 45's, but I would advise most to exhaust the dives they can do on a big single before considering doubles.

They do offer some advantages:

They don't roll around in the back of your pick up truck.

The added mass makes everything happen more slowly under water.

No doubt shortly others will happen along claiming no instruction is necessary and that doubles are simple and self explanatory, but my experience with many new doubles divers compels me to council caution.

In the interest of full disclosure I design and sell BP&W's and have equipped countless divers about to try doubles.

Good luck,

Tobin

 

[dumpsterDiver]

Double tanks are horribly heavy, cumbersome, expensive, bulky and will slow you down in the water. If you need more air, you can buy a single big steel tank and it should have enough capacity to handle most any recreational dive. They will probably cost you double to fill every time you use them.

I read all the stuff on this forum for years and bought a BP/W. It was no big deal to me.

Less comfortable on the boat, much less comfort and support on the surface - since all the lift is in the back they tend to put you face down while diving and while on the surface, and they are much more prone to failure due to pinch flats from the plate cutting the internal bladder, they pretty much REQUIRE you to use an extra strap that goes over your nuts and is a pain to locate and connect on a pitching boat, and the most commonly recommended one piece harness is much harder and slower to get into, than say, a typical BC with adjustable straps. The crotch strap also significantly impedes the instant release of a weight belt in an emergency (unless you go to extra, extra effort to route it a special way).

They do have some advantages. One might be better trim while diving, but the vast majority of recreational divers do NOT use BP/W configuration.

Wanna buy my used wing? It is in great shape.

 

[DogDiver]

Stick with a well fitted jacket BCD. When your ready for advanced diving get the advice form a well trained and experienced instructor.


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[decompression]

I've been teaching for almost 20 yrs......backplate and wing for open water students day one, why learn to overcome a poorly designed Jacket bcd when you can have all the advantages of a bp/w. The backplate grows with you...no buying and selling every couple of years and learning a new piece of gear. It doesn't look as sexy as 90% of the bcds out there but I'd rather save money and have a better position in the water than 14 plastic D rings.


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[cool_hardware52]

I read all the stuff on this forum for years and bought a BP/W. It was no big deal to me.

Less comfortable on the boat, much less comfort and support on the surface - since all the lift is in the back they tend to put you face down while diving and while on the surface

A BP&W can force the diver face down at the surface but only if the harness is poorly adjusted, and…… The diver is grossly overweighted.


Comfort at the surface is a function of proper weighting.

The properly weighted diver needs only a small puff of gas in their wing. This "puff" of gas will be behind the divers shoulders. With a properly adjusted harness this puff of gas is all that is need to lift both the BP&W *and* the diver.

Unlike the typical vest / jacket BC without a crotch strap there is zero need for the properly weighted diver to add massive volumes of gas to their wing.

The over weighted diver OTOH needs a great deal more gas in their wing, and this gas will extend down their back, this is what creates the "forward push" attributed to BP&W and back inflates in general.

With proper setup and proper weighting the dreaded "face forward" is simply not a problem.

Tobin

 

[2airishuman]

Zero reason not to move to a BP&W. A BP&W is a highly adjustable, modular BC, it's not a Fighter Jet. You don't need to buy and replace 1/2 dozen jackets before your are "ready" for a BP&W.

Hmm.

Doubles are:

More expensive, 2 x tanks, bands, 2 x regs

Harder to rent

Yep, I'm willing to pay for safety and deal with the rental hassles (or dive with a single in those instances when no practicable alternative exists), if that's the tradeoff

Heavy

Some. A pair of LP50 steel cylinders is around 10 pounds heavier than an AL-80, right? And you carry a few pounds less lead.

Have enough gas to get you into trouble, and maybe not enough to get you out, get some gas planning education.

To be clear, I'm not asking from a capacity point of view. There are, after all, ponderously large singles.

To benefit from the added "safety" manifolded, Isolated doubles offers required specific knowledge and considerable practice. Without this they only offer additional failure points. Do find qualified instruction, a frightening % of the diving business has no idea how a manifold actually works.

I read the reports and am not entirely convinced that the isolator valve provides any net safety benefit because the incidence of tank, valve, and burst disk failures is vanishingly low. Qualified instruction is a good thing with any equipment, I'll give you that, yes, emphasis on qualified. My (inexperienced) point of view is that regulator free flows and runaway BCD inflators are both a significant contributor to accidents, and the statistics, the anecdotal reports, and the near-miss narratives all bear this out. With doubles, not hard, just close the valve on the offending side and switch to the working reg.

May be more expensive to fill, and the chances of the fill station screwing up is not zero, as many have no idea how an Iso manifold works
Personally I prefer doubles, my "single rig" is doubled up LP 45's, but I would advise most to exhaust the dives they can do on a big single before considering doubles.

They do offer some advantages:

They don't roll around in the back of your pick up truck.

The added mass makes everything happen more slowly under water.

No doubt shortly others will happen along claiming no instruction is necessary and that doubles are simple and self explanatory, but my experience with many new doubles divers compels me to council caution.

In the interest of full disclosure I design and sell BP&W's and have equipped countless divers about to try doubles.

Good luck,

Tobin

Appreciate your words, wisdom, and perspective

2air

 

[decompression]

Further to Tobins comments, the heavily over weighted diver inflates his far to big bcd bladder (55 lbs for a recreational bcd, seriously?) and it's like strapping a marker buoy to your back.

Again, my ow students in bp/w no push ever commented on.

Years ago, my ow students in back inflate bcds (40-50 lbs), why am I being pushed forwards?


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[dumpsterDiver]

Hmm.



Yep, I'm willing to pay for safety and deal with the rental hassles (or dive with a single in those instances when no practicable alternative exists), if that's the tradeoff



Some. A pair of LP50 steel cylinders is around 10 pounds heavier than an AL-80, right? And you carry a few pounds less lead.



To be clear, I'm not asking from a capacity point of view. There are, after all, ponderously large singles.



I read the reports and am not entirely convinced that the isolator valve provides any net safety benefit because the incidence of tank, valve, and burst disk failures is vanishingly low. Qualified instruction is a good thing with any equipment, I'll give you that, yes, emphasis on qualified. My (inexperienced) point of view is that regulator free flows and runaway BCD inflators are both a significant contributor to accidents, and the statistics, the anecdotal reports, and the near-miss narratives all bear this out. With doubles, not hard, just close the valve on the offending side and switch to the working reg.



Appreciate your words, wisdom, and perspective

2air

A manifold with an isolator valve does provide considerable safety, however you are correct that regulator free flows and run away BC inflation is a much more common problem. The solution to a self inflating BC is to disconnect the hose. If you are looking for redundancy, then a 100 cuft steel tank and small pony bottle will be cheaper, easier and less cumbersome than double tanks... In my experience anyway.

If you are dead set on double tanks, then you are pretty much constrained to diving a BP/W.

 

[Scubatude]

I have been selling and teaching my students in BP/W for years and never knew they pushed you forward in the water. Then again, my students are properly weighted. If you start with a BP/W you will not have your "first" BC in a closet soon while you are looking for a new one.

Being of a modular design, BP/W are able to change from single tank to doubles in minutes with a simple change of the wing. Your thoughts are correct about the advantages of doubles, as were the comments about proper training.

I can tell by your comments that you are on the right track and are a thinking diver. The best kind. Good luck and dive safe.