SS BP/W weight question

[DivingCRNA]

I started diving BP/W this summer. I have a half a dozen dives in it now and took a Peak Performance Buoyancy class in it yesterday. After these dives I have the straps adjusted pretty well and the tank does not roll back and forth any more. It is also the most comfortable BC set-up I have ever been in.

We were in the lake yesterday and stayed above the thermocline. It was 82 degree water temp, so I had on the shrorty part of my 2 piece 3 mm suit. This little wetsuit makes me quite negative with the hammerhead steel backplate. I am pretty much neutral in the full 3 mm suit, and positive in a one piece full body 7 mm suit.

With 1/2 of the 3 mm suit on I had to put air in my wing to be neutral for the bouyancy test. Of course as I drained my tank I got to let most of the air out of my BC as the tank became positive.

Is this a problem, other than the issue of not having weight to dump? Am I going to want to use an aluminum plate for when I use less exposure protection, or can the steel plate serve all my needs?

I hope this isn't all too confusing.

Thanks,

 

[Don Burke]

Not having weight to ditch is the only issue.

If you have a BC failure, you may find yourself ditching the tank, BP/wing ,and regulator to stay on the surface.

I can use a steel BP with an AL80 and a 5/3 and have about eight pounds on my belt in seawater.

At one time I could use a steel 112 with my steel backplate. Since I lost some fat, I will have to get an aluminum plate so I can have enough ditchable weight.

 

[halocline]

Actually, there are a few other issues to think about, although they're no big deal. One is that fine control over buoyancy is more difficult with more air in your wing than it is with less; so using the steel plate in situations where you're negative with no lead means you'll work more to stay neutral during the dive, especially as you change depths. The other thing is trim is affected; you may be top heavy in that set up. If either/both of these things is a bother, probably you'd find an aluminum plate better for you in those situations. I'm assuming you were diving with an AL80; switch to a steel tank and you could really be top-heavy with your plate.

The no ditchable weight issue is something to think about, although I have the same situation and console myself by knowing that if I ever had to ditch the rig to stay buoyant (unlikely) where I typically dive in fresh water, it's shallow enough so I could retrieve the rig later.

 

[DivingCRNA]

I did play with trim yesterday. My fins are actually negative, so once I moved the aluminum 80 tank down a little my trim was pretty good. I could hover in diving position and not have trouble.

I do not add much air to the BC at the start of the dive. Just a couple short shots of air and I am set.

I do plan to just dump the whole rig if I have to lose the weight. Also, my knife could cut the harness no problem if I had to do that. But a BP/W comes of faster than my old BC anyday.

 

[GreenDiverDown]

With 1/2 of the 3 mm suit on I had to put air in my wing to be neutral for the bouyancy test.

How did you do your bouyancy test...full or nearly empty tank? At the surface or at 10-15 ft. or so? Were you in fresh or salt water and where will you be diving?

Of course as I drained my tank I got to let most of the air out of my BC as the tank became positive.

Specifically, how did this affect your bouyancy?

Is this a problem, other than the issue of not having weight to dump?

You don't need ditchable weight.

Am I going to want to use an aluminum plate for when I use less exposure protection, or can the steel plate serve all my needs?

If you want to dial in your weighting you may want to get an Al BP. But in general, a SS plate at 6# is very usable with thin exposure protection.
And an 18# wing is perfect for this situation.

 

[scubadobadoo]

I agree with not needing ditchable weight and that adding air to your BC to compensate for being too heavy is also troublesome. Perhaps the AL plate is the answer in warmer water assuming $ isn't a concern. Not to mention the pain of changing the straps.

Stephen above asks some good questions in light of the fact that you are really close here to balancing but may have to change gear a little due to the fact that you may be too heavy. You may not have another option other than adding a little air when diving warm, fresh water as you said. Not such a bad thing for one out of ten dives as long as you take it slowly and are careful and aren't going too deep. Sounds like you have pretty much figured this all out. Good luck and have fun!