BP/W: I officially don't get it

[D_B]

I am big into photography (but not writing on slates ). I have no idea why you think BP/Ws are a bad idea for photographers? Would be interested in some elaboration given I use a BP/W now and find it a great deal more comfortable than the jacket or back-inflate BCs I have used in the past.

I've seen posts by photogs that like their jacket type BC cause of that wrap around air bladder allows more positions to be stable at when on their side

My first impressions ......

The one thing I noticed right from the start is a lower SAC rate. Even though my rear inflation BCD was set up very clean it can not come close to how clean the BP/W is. Of course I dive with in the DIR equipment guide lines. The other thing was I needed 3lbs less to sink the BP/W. After a bunch of adjustment dives I have much more control in the water then before. This is just my experience with the BP/W.

good point, it takes a lb or two to sink a normal BC

 

[cool_hardware52]

I've seen posts by photogs that like their jacket type BC cause of that wrap around air bladder allows more positions to be stable at when on their side

Unless you are overweighted, have a LOT of gas, or a very compressible very buoyant wetsuit, (or all three) there isn't going to be much gas in the diver's bc anyway....

good point, it takes a lb or two to sink a normal BC

Depends on you definition of normal. I routinely see conventional BC that require 3-4 lbs of lead to sink with an empty bladder, simply due to the foam padding. Add to that BC designs that trap gas, i.e. hard to fully vent, and the extra ballast required to use can be 4-6 lbs.

Tobin

 

[D_B]

I could see the point that was being made by him , I know that with my steel HP100 on one side, and my 7mm suit on the other, my sidways teter totter doesn't like 90*

 

[Sas]

I've seen posts by photogs that like their jacket type BC cause of that wrap around air bladder allows more positions to be stable at when on their side

I have not heard this from any photographer I know. I do not find it the case myself too, as the tank is far less stable in a standard BC.

As cool_hardware52 pointed out, if you are correctly weighted you do not need a lot of air in the wing anyway for most types of setups (excl the examples he gave) so it should be a moot point.

good point, it takes a lb or two to sink a normal BC

Sometimes more. My old BC took 4lbs as I dropped 10lb when switching from it to a BP/W with SS BP (BP is 6lb).

 

[D_B]

position , not tank, stability ..
.. I just know for me, with a buoyant wetsuit on one side, and heavy tank on the other side , my teeter wants to totter after about 50* or so

it's -10lbs on one side, + something lbs wetsuit on the other side ... hard to balance that out

 

[elan]

Sometimes more. My old BC took 4lbs as I dropped 10lb when switching from it to a BP/W with SS BP (BP is 6lb).

Yes I figured out mine takes at least 3-4 to sink it.

 

[peterbj7]

Ahhh, no. Rear inflation BC's, sometimes called Tech BC's, have the bladder in the back, just like a wing. Jacket style BC's are the wrap-around bladders.

Yes I know that, but I think people were confusing those with regular BCs. I can't see the point in rear inflation BCs.

 

[Cave Bum]

Yes I know that, but I think people were confusing those with regular BCs. I can't see the point in rear inflation BCs.

The point of rear inflation BC's as is the point of BP/W's and the Transpac is that they tend to hold you horizontal and, also, you're less likely to turn 'turtle'.

If you get a little creative with them and move the weights up a bit, you become even more horizontal. The flatter you are in the water, the more streamlined, like an airplane in flight, the easier it is to move through the water and less gas you use.

This is the whole idea behind Bill Main's Hogathian Method. Smooth, low profile, low drag and fast moving are the key points to the system, if you talk to Bill. It has, however, been somewhat perverted both under the Hogarthian name and under the DIR brand. One thing in specific is I don't think I've ever seen Bill wear a dry suit. Too much drag...

On another board recently, Jarrod Jablonski, acknowledged his DIR gear configuration was from Bill Main’s Hogarthian system, praised Bill’s contribution and said he’d changed the name because parts of his DIR system conflicted with the principles Bill professed, in specific Bill believed in deep air and JJ believed in Helium. The rigging of the gear however is pretty much the same between Hogarthian and DIR.

At any rate, that's the point of it…

Be safe and have fun in the water! Bruce

 

[Adobo]

bp/w's are really versatile. the bc's are excellent for divers with a little more experience. Bp/ws really allow you to achieve best buoyancy, by laying you horizontally, fine tuning the air in the bc and allowing you to use the air in your lungs to rise and fall through the water collumns. if your into stuff like photography and writing stuff on slates, then no, theyre probably not right for you.

In terms of achieving stable horizontal trim, I do not see why one (a rear inflate BC vs. a BP/W system) would be superior to another. This is a function of being properly weighted and proper placement of the weight. The rest of it is diver skill - just like a rider balances himself on a bicycle.

I don't know what you mean when you say "best buoyancy", however, with regards to having good command of one's buoyancy, it is a function of having a sense of when to add gas to and when to expel gas from your lungs. Having minimal gas in your wing and drysuit definitely makes things easier but the amount of gas in your wing and drysuit has nothing to do with the type of BC you use, that is function of being properly weighted and the amount of gas in your tanks that you need to offset.

WRT photography and slates, there is absolutely no reason that one cannot accomplish tasks such as these in either a back inflate BC or a BP/W. In fact, just about all of my dive buddies use a BP/W system and they all can do complex tasks such as taking pictures, writing on wet notes, deploying SMBs, running reels, valve drills, gas sharing, etc. And they all can do these tasks in mid-water.

But just so it is clear, I personally find the backplate system superior. In this system, there are many well defined, well tested methods of adding and stowing additional gear that you will need in different types of dives. Some examples:
- canister lights are easily added on to the waist strap and secured by a second buckle.
- back up lights are easily stowed on the torso.
- crotch strap D-ring for tow behind scooter.
- plenty of d-rings for a reel.
- can easily integrate a stage/deco/pony bottle

I know one can accomplish all this with a back inflate bc but there is plenty of trial error that will be required.

 

[Adobo]

The other thing was I needed 3lbs less to sink the BP/W. After a bunch of adjustment dives I have much more control in the water then before. This is just my experience with the BP/W.

Did you factor in the weight of the backplate and all the other doohickeys that are part of the rig? My steel plate with STA, stainless steel buckles, cambands with stainless steel buckles weighed in at over 11lbs. Whether the weight is on your weight belt or on your rig, it is still weight.