A Weighty Question. . .

[Eino Maki]

Hi to All!
In my short dive career of 29 dives, I have settled on 12 pounds of weight in salt water as my ideal amount. These dives have all been made using 80 cf steel tanks. I am leaving for Little Cayman on Saturday for a week of diving. From looking over the resorts web site, it looks like we might be using aluminum tanks. I understand that aluminum tanks start out with negative bouyancy but end up with positive bouyancy at the end of the dive. My question is, how much additional weight will I need to compensate for this additional buoyancy at the end of the dive? I don't want to have to struggle to stay at 15 feet for my safety stop.
Thanks in advance!
Eino

[LKunze]

A luxfer Aluminum 80 tank is 4.4 lbs. positive when completely empty. Since you should be surfacing with at least 500 psi in your tank at the end of a dive it would be a little less positive than that. I normally dive steel tanks but when I've switched to an aluminum tank I have always added an extra 3 lbs. and that's worked out fine for me.

[DanL]

Eino,
Noticed you said you dive salt water. Where do you normally dive and what weight wetsuit do you use? Is your wetsuit at Cayman going to be different from your normal wetsuit?
Anyway - it all probably doesn't matter. EVERY dive operation I've ever dived with asks how much weight you typically use, tank type, exposure suit, etc and recommends a starting weight. The DM's are usually very close in their weight recommendations, and they will help you get your weight right on the mark within a dive or two if you ask them to help out. Also, the DM's carry extra weight. Pre-arrange a signal to get weight from your DM toward the end of the dive if you find you are getting too bouyant.
It's GREAT that you're thinking about this, asking advice and working it out in your planning. But don't worry - rely on getting assistance from your DM in getting set up right for the local diving conditions.
PS - by the end of a week, a good DM will help you work your weight down and trim you out. They are in the water every day and see every type of diver. They can really help you improve. You'll have a wonderful time!

[willadams67]

I use aluminum 80's and I get my weights set perfect with all of my gear on and then add 4#'s. I think you could get away with 3 #'s but I don't have 1.5# weights. Dan is right though your charter should be able to fine tune your weight for you if you are having any troubles. Have a nice trip and happy diving!

[beeger]

All other things being equal (exposure protection, BC, water, accessories, etc.) you are probably looking at adding about 3-4 extra pounds. Most people find that they can shed some weight as they get more and more comfortable with diving, and learn proper ascent/descent procedures. I wouldn't be surprised at all if you found yourself dropping a couple pounds from your "adjusted" weight just based on that alone. Maybe start with 4 lbs extra and work your way down (forgive the pun) from there. If you do find yourself "struggling" to stay down on a safety stop: 1) make *sure* you have all the air out of the BC; 2) focus on long, slow exhalations ... struggling will just make you breathe harder and make buoyancy control that much more difficult; 3) Relax - remember to slow your ascents throughout the dive and you'll be fine.

Little Cayman is beautiful. Sites like Bloody Bay Wall and Mixing Bowl are amazing.

[Eino Maki]

LKunze, DanL, willadams and beeger,
Thank You for your responses to my question. I have only logged one dive here in fresh water. I dove
last year and this past Feb. in Cozumel. I use a 3mm full wetsuit. It's the same on that I'll use next
week. I have gradually cut my weight down to 12. I could probably get by ok with 10, but I hate to
experiment on a boat dive and find out I can't sink. A couple of our dives this years were affected
by divers who couldn't get down. Weight wasn't their only problem though. The rest of the group had
to huddle and wait on the bottom while the DM got them back on the boat.
My air consumption is getting better with every dive. I get really cold though, even though the water
was 81 degrees and I had the full suit. After 45-50 minutes, the only thing keeping my teeth from chattering
is the mouthpiece. I'll sort of 'shiver' from the cold and exhale a huge blast of air. I'm taking a new 7mm
hood to Cayman to try to cut down on this. My dive buddy, who dives in a shorty, will tease me mercilessly.
I'll just tell him, "When I get hot, I'll take the hood off."
I'd like to make some dives at Square Lake this summer. I don't live too far away, up near Taylors Falls.
I wish I had taken up scuba sooner. I'm 53.
I'll check in when I get back on April 3rd.
Thanks again,

Jeff (Eino - not his real name)

[DanL]

Jeff,
If you're cold, get whatever wetsuit you need to stay warm. Don't worry what your divebuddy thinks. The DM's in Cozumel this Feb and March were wearing 5 mils with hoods. I wore a 3mil with hooded vest in Florida last year and was barely warm enough.
If you're at Taylors Falls, you're nearer Square Lake and Wazee than many of us.
I started diving 2 years ago at 51. It's been a great incentive to get/stay in shape and stay active. You'll have a blast - very good group of diver people in the area!

[jasondbaker]

Jeff, your air consumption will improve when you wear the right thermal protection. I bet the hood will help significantly. Also make sure you aren't getting chilled before you get into the water. Sometimes people don't realize how the boat ride out can affect their body.

[Freedive WI]

Don't be affraid to wear extra layers of rubber to stay warm.

On trips to the Bahamas I've worn a full 6.5 mm suit with an attached hood and never got too warm. After my last trip to Cabo San Lucas I swore that I'd wear a drysuit the next time I came back. As it was I wore a 7mm suit, with a hood, and the dive guide ran out of air before my buddy and I had even broken 1800 psi. keeping warm is half the battle in air consumption.

Another thing to keep in mind is that a wet wetsuit will freeze you out pretty darn quick once you are out of the water.

When working on a charter boat on Lake Michigan, we tell everyone to peel off their wetsuits in between dives to warm up. The people that listen to us make long second dives, those that wear their wetsuits throughout their surface intervals are lucky to make a 15 minute dive on their second time around. The same holds true for tropical diving. It might take longer in 80 degree water, but you'll still freeze out eventually.

You'll drop at least 5 pounds off of your weight belt if you keep diving. 12 pounds for a warm water dive is a lot of weight, but it just takes time in the water to bring it down.

The next time your on a trip try and do a shore dive at the begining of your week so that you can really dial in how much weight you need. At the end of your first dive wait until you drop down to 500 psi and play around in 10' of water, with an empty BC, to see how much weight you can really get rid of. It works best to do this at the end of a nice long dive because all of the air bubbles are worked out of your BC and wetsuit- which can't be said at the begining of the dive.

Jon