A question on BP/W single tank mounting

[cool_hardware52]

Where's your tank position in relation to the cam bands/wing. If the tank is sitting too high that'll throw you forward. Quite a few people who go to a BP/W without someone experienced helping them set it up end up with the tank too high and pitch forward.

Yup, or too low.

Me? The tank belongs where I have the best chance of reaching the valve, and adjust trim around that.

It's also pretty common for divers to be butt heavy and over compensate with body position and end up falling forward, particularly with singles. The reverse is often true in doubles.

What I recommend is:

1) Determine your idea total ballast

2) Find a dive site with a horizontal bottom that is ok to lie on, institutional pools are great.

3) Dump your BC and lie face down, get into the "skydiver" position

4) Add puffs of gas to your BC until a big deep breath just lifts you off the bottom.

5) If your knees are on the bottom and your chest is rising you need to move ballast north, for example from a belt to the plate, or raise the tank position. (This is the most common condition for single tank divers) If your chest is on the bottom and your knees are floating away move ballast south.(This is more common in doubles)

Repeat with a near empty tank to see if you need to compromise ballast location.

Done.

Tobin

 

[scrane]

MrC:
Right now the tank falls just into the contour of the wing, i.e. the tank does not overlap the top of the wing nor is there a void between the tank and the top of wing. It just kind of nestles in there. It is positioned such that when I lean my head back I don't hit the first stage. The hoses from the reg rest on the top of the bag.There is definitely room for experimentation as to the position of the plate to the wing to the tank. Thanks.

 

[scrane]

Tobin,
Thanks for the tip. This makes a lot of sense.
I hope I haven't overemphasized the problem. I can definitely dive without difficulty, and when I get to salt water I can determine how much weight I need to be neutral, and where it should go.
But I really do like your test! Foolproof.

 

[scrane]

One additional question. Can there be a problem when unloading the tank in the typical recess on the dive boat that the wing will pinch between the bottom of the plate and the boat?

 

[seeker242]

One additional question. Can there be a problem when unloading the tank in the typical recess on the dive boat that the wing will pinch between the bottom of the plate and the boat?

It depends entirely on the boat and how they have the racks set up. It has happened to people.

 

[Bierstadt]

I am pretty paranoid about the pinching issue, but as long as you always keep a moderate amount of air in your wing I think you'd have to be really aggressive in order to pinch. Dropping and pinching is another story, but for normal use the air should help keep your wing safe.

 

[USMC CPL.]

I have this one. It's good for $299 The only thing I don't particularly like is the pull dump but it's not a big deal.

DGX Custom - DGX Singles Harness / Backplate / Wing Package

It doesn't require an sta and it doesn't roll around. It does come with screws to secure bp to wing but they are just for convenience when assembling/disassembling

I bought this bp/w and love it.

 

[stuartv]

One additional question. Can there be a problem when unloading the tank in the typical recess on the dive boat that the wing will pinch between the bottom of the plate and the boat?

CAN there? Yes. Shorter tanks and bigger wings are more likely. E.g. An AL63 with a 30# wing is more likely to have the wing get pinched when you drop it into a boat bench tank holder than an HP120 with a 23# wing. But, really, neither is THAT likely.

I pinched a hole into a wing I used to have. Actually, it put 3 holes in the bladder. I don't know for sure, but I am pretty sure it happened when I was trying to swap my BP/W from one tank to another between dives, on a pitching boat. I suspect I accidentally dropped the BP/W onto the bench and the corner of the plate landed on one side of the lower part of the wing.

That is one reason why I now use ScubaPro-style Quick Release tank straps, instead of cam bands, and I have used a piece of string (cave line) to make a loop that is tied to my BP. I use the loop to hang my BP on the tank - just like a lot of integrated BCDs do, using a loop of webbing. It is tied to hold the BP at the right height, so it can just hang there while I fasten the tank straps. I don't have to hold it up with one hand while I try and fasten tank straps with the other. And I don't risk dropping the BP/W in the process...

 

[dmaziuk]

One additional question. Can there be a problem when unloading the tank in the typical recess on the dive boat that the wing will pinch between the bottom of the plate and the boat?

Yes. It's just something to keep an eye on, e.g. put a hand in there when sitting down after a dive, watch it when changing tanks. As others said, a bit of air in the wing helps.

Also keep in mind that swapping tanks on a boat like that is more hassle with 2 cambands, esp. if you have rubber no-slip pads on them. It helps to have 3 hands: one to hold the tank out, one to hold the bp&w, and one to slide the bands down on the tank.

 

[scrane]

Thanks for the replies concerning pinching the bladder. I guess I'll have to go against my natural instinct and be careful.