70 replies to this topic

[Walter]

I personally think it is better to go slightly heavy on the first dive and if you have no problem going down...PLUS....no problem maintaining depth as your tank drains...then take off two pounds.

Slightly negative is better than slightly positive. OTOH, neutral is even better. The problem is most divers aren't slightly negative, they are grossly negative. That results in divers dying. It's worth the time it takes to get it right.

[DandyDon]

Walter must be off having fun, or he would have posted already, I'm sure. Oh, there he is! Now that I spent several minutes writing and posting this, I guess I'll leave it. Hope I got his part right here...?

Anyway, he likes to teach a diver to be able to float at eye level with full lungs, empty BC and nearly empty tank, then sink after exhaling. A standard aluminum 80 cubic foot tank - the most common in use today - is about 3# more buoyant with 500 pounds of air pressure than at 3,000 pounds, so - if you can sink slowly with a nearly empty tank, you should sink easily with a full one. Like DrBill, I like to be just a little more negative or weighted - him so she can stay down in position easily while invading the privacy of the ocean's residents, me so I know I can get down quickly after surfacing if I see a boat coming my way.

You'll need a few more pounds in saltwater than in fresh, as the dissolved salts make the water denser and you more buoyant. Maye 3 or 4 more?

The same in a 3 mil suit as compared to just a swimsuit in the pool - maybe 3 or 4 more.

You'd need more a little more in a new wet suit than an old one, as some of the buoyancy leaks out after they've been deep and under pressure several times.

And if you're new to Scuba, you'll need more than the more experienced, 'cause newbies never relax enough to exhale all the way. I once went to Cozumel with a tiny newbie gal who used more weight than I did!

It's best to initial weight checks in a pool or a shallow beach dive, for with all the possible confusion of weighting, you might start with way too much. Wouldn't want you sinking rapidly down a deep wall. If you start with too little, don't get frustrated; just get more lead. And - keep it fun!

Edited by DandyDon, 08 May 2004 - 11:23 AM.

[scubahoney]

Walter- I think you are going to be my Yoda-you always know the answer to everything. From here on out I dub you Yoda (if thats kewl with you, lol).
I got the email..thanks so much...very helpful, and I can't wait to use it.
Dandydon-you're right abou the newbie stuff...I still suck down air b/c being underwater still makes me a little nervous. I'm always afraid that I forgot something!

[Coo's Toe]

Dang it Walter, you beat me to the punch, and now the ladies are singing "YES YES YES" to you.... I really should have checked in last night to see what was going on.

You did forget one small thing, though. Add six pounds to compensate for the air in the tank ( if you're using an aluminum 80 ).

Here's the process:

Get neutral in the pool, with a full tank. No air in BC and full lungs should have you floating at eye level. Exhaling completely should cause you to sink. Weigh yourself and gear. Multiply this weight by .256 to account for difference between fresh and salt water, then add six pounds to account for the air in the tank. You will be correctly weighted.

Or:

Get neutral in the ocean with a full tank. Add six pounds for the air. You're done.

Edited by Coo's Toe, 08 May 2004 - 12:58 PM.

[Coo's Toe]

Sorry Walter!!!

I just re-read your post and saw you are recommending this be done with a tank at 500 psi, so you are totally correct. My bad.

I've always recommended using full tanks, though, because this way you can do a check before the dive, and people are usually ready to go with a full tank. Either method works though.

[Coo's Toe]

Walter- I think you are going to be my Yoda-you always know the answer to everything. From here on out I dub you Yoda (if thats kewl with you, lol).

If he get's to be Yoda, can I be Darth Vader? I'm dressed all in black, in tune with the dark side, and I'm skilled with a lightsaber ( I'm talking about my HID light, girls, so behave. )

[scubahoney]

Yes, you are now offically dubbed Darth Vader...
hm..if you are Darth and Walter is Yoda, what does that make me?!

[Coo's Toe]

Uh... "Your Highness"???

[Walter]

Darlin',

As long as you keep screaming "YES! YES! YES! YES!" I don't care if you do think I look like Yoda.

Erin,

You're correct. If she's using an AL 80 (or any tank with that volume) and doing the weight check with a full tank, add 6 lbs for the air. Of course, if she's using a different size tank, the amount to add will vary.

You slipped a decimal. Multiplying by .256 would have that 145 lb diver in my example adding 37 lbs. That would be dangerously overweighted. Use .025 instead. While .0256 might be more precise, we're dealing with 1 lb (or larger) weights and adding that .0006 gives us results in ounces. That's not helpful. Drinking a root beer will change my buoyancy more.

Walter

[scubahoney]

Hey Walter, I never said you LOOKED like Yoda..you are just all-knowing like the creepy little midget. Don't worry, you don't resemble him at all! LOL

[Coo's Toe]

Oh geez, you caught one of my rare typing errors! Yes... .0256 is what I meant to say.

Sure the .0006 might be taking it to the ultra-geek level, but weren't we trying to prove it's more science than art?

[Coo's Toe]

Hey Walter, I never said you LOOKED like Yoda..you are just all-knowing like the creepy little midget. Don't worry, you don't resemble him at all! LOL

Sheesh! Now I'll be picturing little green midgets with big ears running around saying "Use the force, Darlin"!!!

[scubahoney]

YES! YES! YES CT!...Science! not art!

[DandyDon]

Drinking a root beer will change my buoyancy more.

Eating beans the night before adds 2# to my needs everytime!

[Coo's Toe]

YES! YES! YES CT!...Science! not art!

Thanks, I needed that!!!