Aldora tank buoyancy

[ronscuba]

What are the buoyancy characteristics of their tanks vs. an standard aluminum 80 ?

 

[DjDiverDan]

Exact comparisons depend on what size you are tallking about, Steel 80, Steel 100, or Steel 120, but as a general matter all HP Steel tanks are going to be heavier than AL tanks, and will not go positively buoyant when you get down to 500-700 psi, as Aluminum tanks will. Whether that is good or bad really depends on the diver. I love steel tanks, but I am large, fat (and therefore buoyant) and need a lot of lead to allow me to descend. With an AL 100 tank, I use 17-19 pounds of lead. I could probably descend without effort with 15-16, but then run the risk of not having enough weight to stay comfortably submerged on a safety stop if my tank gets to 500 psi. With a Steel 120, the last time I logged a dive with that tank, I only needed 11 pounds. BUT, if you are one of those divers who can comfortably descend and stay down with 4-6 pounds on an AL 80, the Steel tanks may make you feel overweighted.

 

[boulderjohn]

Back when I still used a standard back inflate BCD, I usually used 8 pounds of lead with an AL 80. When I dived with a steel HP 120 instead, I could do the dive with no extra weight at all, but I usually carried a 2 pound weight.

 

[ronscuba]

It's been many years since I dove with Aldora. Does anyone know what tanks they use ? I know they are larger than standard aluminum 80.

In water temps above 80, I prefer to dive without a wetsuit and don't use any extra weight.

 

[tbone1004]

ask them or check the tanks yourself.... probably al100's

 

[boulderjohn]

When I dived with them, I used the steel HP 120s I mentioned in my response. Some of the smaller people in our group used HP 100s.

 

[Zman96]

They use HP 120 but you can request smaller tanks. I use a back plate and I find the steel tanks to be quite heavy. When I use AL100's I need no extra weight but will sometimes carry 2 lbs to start just in case I have become a little more buoyant.

 

[ronscuba]

ask them or check the tanks yourself.... probably al100's

I know, but Scubaboard is so active sometimes you get an answer quicker.

I just sent them an email.

I'd like to know in advance so I can plan whether or not to bring a wetsuit to offset the tank being too negative.

 

[scubafanatic]

I know, but Scubaboard is so active sometimes you get an answer quicker.

I just sent them an email.

I'd like to know in advance so I can plan whether or not to bring a wetsuit to offset the tank being too negative.

As the larger tanks lead to longer dive times, and it's 'winter' now (with cooler water temps) you'd likely want to wear a wetsuit anyway.

 

[DjDiverDan]

I just checked on Scuba.com, and according to that source, an AL 80 tank is about 1.8 lbs negative buoyancy when full (3,000 psi), and goes to 2.6 lbs positive buoyancy at 500 psi. A HP Steel 80 is 9 lbs negatively buoyant at full (3500 psi) and goes to about 3 lbs negative buoyancy at <100 psi. So a diver should use 6-7 lbs less lead switching from an AL 80 to a Steel 80. I couldn't find info on the HP Steel 100 or the HP Steel 120, but I would guess that you could drop an additional 2 lbs for the 100, and 4 lbs for the 120.