feet floating with Single Tank BP/Wing

[bradlw]

I'm looking for help with weighting suggestions.

OK, so getting ready to get back in the water after a very long time off. I've been working on getting my set-up sorted a bit

Just before life getting in the way of diving, i had just come out of training with back mounted doubles, getting several technical certs. and I was liking the BP/Wing set-up, so I bought a Halcyon SS BP with a single tank wing for recreational use. I only dove twice with it before it ended up in storage for a very long time.

It's still in great shape and I changed out the LPI, gaskets, and the OPV

just for reference, I ran some checks in my swimming pool
The BC as configured has about 18 pounds reserve lift and is negative 4.65# submerged and deflated

So I jumped into the pool yesterday with my 3mm farmer john on, wanting to figure out how much lead I need
I was strapped to an aluminum 80 tank with I think it was 250-300psi in it. A catalina that per my online research, is approx 4 pounds buoyant when empty.

I have weight pockets on my BP's waist strap, just forward of my hip D-Rings...so just forward of my hip bones. I don't love the location but it's the best way I can think of to get weight low and forward

When I dove it way back when I, it was a a very similar suit and I had a 30CF pony side slung
I had 4 pounds of lead in trim pockets on the top tank strap. I noted that it was extremely back and head heavy

So yesterday I had nohing in the tank strap pockets
and I found that 3 pounds in each hip pocket was pretty good, but 4 pounds in each gave me a little better margin to stay neutral submurged. 3-1/2 pounds would probably be about perfect with that empty tank, but I'm planning on floating anyway when I'm down to 250 psi, so I'm thinking 3 pounds per side is probably good....

But my problem is that my feet were floating up.

I didn't have my fins on, so I'm hoping that'll be enough.
and since I won't be diving with such an empty tank, I'm thinking that'll change things too

But if it's not and I need a little more weight down low, do you have any suggestions

 

[inquis]

Definitely test with your fins on. After that, some possibilities:

• Bungee a lead brick to the crotch strap. This can sit in the "loop" where attached to the plate to take the majority of weight.
• Use an AL plate and 4 or 5 lb bricks on the waist.
• Negatively buoyant fins like Jets or F1s

 

[Endler's]

A rubber weight belt would place weight lower on hips. Weight belt has additional advantages of making you close to neutrally buoyant, if you had to remove BC underwater. Less weight on BC, also makes it easier to fit straps around tank.

 

[Jcp2]

Al80 is butt light when close to empty

 

[FishWatcher747]

Agree with Inquis.

Also possible.
1. Move tank lower.
2. Move wing up relative to backplate.. My backplate has 3 possible positions for the wing.

 

[inquis]

Move wing up relative to backplate.

On this one, I'd say the wing should be empty (negligible lift) at these pressures if properly weighted. I agree that wing placement is important, but that should be done with full tanks after first fixing the empty tank/wing trim. This aligns the wing lift and gas mass so trim is consistent from dive start to finish.

 

[inquis]

Al80 is butt light when close to empty

All tanks are butt light when close to empty. (Don't forget about the valve and regulator.)

 

[bradlw]

On this one, I'd say the wing should be empty (negligible lift) at these pressures if properly weighted. I agree that wing placement is important, but that should be done with full tanks after first fixing the empty tank/wing trim. This aligns the wing lift and gas mass so trim is consistent from dive start to finish.

yes, it was as absolutely as empty as I could get it...

But this idea about what to do after I get the empty trim dialed in had not occured to me, so thanks to you and to @fishwasher747 for bringing it up!