Difference between Double steels & AL 80's

[lv2dive]

Something happened to my post when I went to edit it....

Unfortunately the pool with the wetsuit is not an option. No one at my LDS has any doubled AL80's (everyone dives steels). I have called & asked around. An out- of- town friend has offered a set for me to try, at a big get- together in late Nov. By then the water will be much to cold (for me) to dive a wetsuit of any kind. I can either dive the wetsuit at home with steels (which really doesn't help me) or dive the AL80's at the quarry with my thickest undies (650gm). I'm guessing those thicker undies will be close to, or more buoyant than the 7mm wetsuit. Being a bit negative (as long as I'm balanced) shouldn't be a huge issue for me. I do have 5# & 7# V-weights & a 5# tail weight to play with. I plan to dive them both full & then drain them to <500psi to get a good idea of the buoyancy swing.

Tammy - how cold is the quarry? The reason I am asking - and I am just throwing this out there - is that I am total wuss and get cold pretty easily as well (not as quickly as Jax, but still pretty quickly!) Anyway, I was absolutely floored that for volunteer dives in the Beluga exhibit at the aquarium, we wear 7MM wetsuits vs. drysuits. I believe the water is in the mid-40's and I have been surprised that I actually haven't been very cold at all. The only dive I had I had problem was the dive I tried a wetsuit that was size bigger than the staff recommended (bc I didn't believe the size they said was the right size) and I WAS cold on that dive. I wouldn't suggest the wetsuit as a get in, get out and hang out, get back in again... but it may not be a bad idea to do one dive, to determine if the estimates you made based on your drysuit weighting are correct. Just a thought!

 

[ianr33]

I have some experience switching from a single AL80 to double AL80's during a couple trips. Generally, I feel the switch between the tanks didn't need any adjustment in additional ballast. The additional positive buoyancy of the second tank is essentially offset by the negative buoyancy of the bands, manifold and extra regulator. I was able to breathe the doubles down pretty far and was neutral at the last deco stop.

Totally agree with that . Weighting for double 80's will be the same as a single 80.

Trim is a different issue. 80's tend to get butt light when empty so you may well need some weight low down.

 

[tstormdiver]

Tammy - how cold is the quarry? The reason I am asking - and I am just throwing this out there - is that I am total wuss and get cold pretty easily as well (not as quickly as Jax, but still pretty quickly!) Anyway, I was absolutely floored that for volunteer dives in the Beluga exhibit at the aquarium, we wear 7MM wetsuits vs. drysuits. I believe the water is in the mid-40's and I have been surprised that I actually haven't been very cold at all. The only dive I had I had problem was the dive I tried a wetsuit that was size bigger than the staff recommended (bc I didn't believe the size they said was the right size) and I WAS cold on that dive. I wouldn't suggest the wetsuit as a get in, get out and hang out, get back in again... but it may not be a bad idea to do one dive, to determine if the estimates you made based on your drysuit weighting are correct. Just a thought!

Right now the quarry is in the upper 50's on the surface to about 35 ft. Below that it is 45 degrees. I've dove that cold before in a 2pc 7mm & froze my tushie off. I have not yet determined any weighting yet. I have some friends that will be meeting up with me at the local quarry in about 3 weeks, who have a set that they will let me borrow to determine what I may need. By then, with the weather like it is now, the waters will probably be in the low 50's or such.

 

[tstormdiver]

Totally agree with that . Weighting for double 80's will be the same as a single 80.

Trim is a different issue. 80's tend to get butt light when empty so you may well need some weight low down.

That's about what I thought. Another friend of mine tried to do her AN/DP course in 80's. Her first time in doubles & drysuit. Needless to say, it was a disaster. It kept turning her on her head. I knew from that there were some different trim issues compared to the steels. Thanks.

 

[ianr33]

The easiest vacation fix is to take a couple of extra camstraps (metal buckles) and thread a weight onto each strap (4 lbs?) Put the camstraps on the bottom of the tanks.