How much ditchable weight should one have?

Running into a little problem.

I am using:
S/S bp (9lbs.)
S/S STA (2-3 lbs.)
HP 120 steel tank
7mm wetsuit (semi-dry)
ZERO ditchable weight


I weigh 185lbs., little to no fat, and sink like a rock. I need to lighten my rig to be able to have some ditchable weight in either a weight belt/harness, or integrated. How much is too little ditchable weight, and how much is.... well... too much?

Would you go with an AL tank, or lighter bp?

I thought that I should try to have as little ditchable weight as possible. But wanted to know your thoughts.

Thanks to anyone who takes time to post.

cybordolphin once bubbled...

Would you go with an AL tank, or lighter bp?

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Well... a lighter BP would be the cheapest and easiest way to go, but...

What is your tank? The first thing to remember is that with a 120, you've got an extra 9 lbs at the start of the dive. Make sure you're talking about being too heavy at the end of the dive. Also look at the tank specifications for the brand you have. If you have faber tanks, you'll probably need to go with a different tank,as faber tanks are noteably heavier than others.

I thought that I should try to have as little ditchable weight as possible. But wanted to know your thoughts.

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If you want my opinion... The first question is can you swim your rig with no air in your BC at depth early in your dive? If not, then you definately need some ditchable weight. But you don't want so much that you can't control your ascent if you have to ditch weight in the end of the dive.

I'm _personally_ shooting for ditchable weight == to the ballast the air in the tank provides, split up so I can ditch all, half, or none depending on where I am in the dive.

Tank is a PST HP120.

So.... as long as I can swim up at the beginning of my dive with full tank, I may not need any ditchable weight? Providing that at the end of my dive.... I still am negative?

Could this mean that there are divers who do not need any ditchable weight?

"Don't dive wet steel."

You've run into the best example of why that is, in general, a good rule.

As to how much ditchable weight: you should be able to make your rig neutral with no air in your wing, is the general recommendation.

Those are just guidelines, of course, but from what I've heard trying to swim up steel on a heavy rig in a wetsuit is pretty much insanely difficult... and then you would probably need to ditch your rig at the surface.

(if you need that much air, I believe the general recommendation is doubled AL 80's)

jeff

cybordolphin once bubbled...
Could this mean that there are divers who do not need any ditchable weight?

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Yes... but it's not the best idea. Try this... after your safety stop is done, dump your BC and try to tread water at 15 ft for 3 minutes [e.g. practicing a deco stop with no air in your BC]. You'll quickly find you'd have liked to have been able to ditch enough weight to be neutral with the extra ballast in your tank...

I personally have been in the market for steel 100s, and came across a killer deal for fabers with 6 dives on them [and I was present during those 6 dives]. While I loved the deal, they would have left me with ~ 4 lbs needed... _way_ too little in my mind.