AL doubles?

[Scott]

What happens when you have to actually use that reserve gas someday?

You use it.
I edited my original to add more information.
I think Sinbad is just looking at the specs for the cylinder with valve.
i know I have more than eight pounds of 'stuff' to offset the difference. Regs, lights, fins,

 

[Tug]

When diving wet in a 3mm suit, I love AL80 doubles. They trim out great and with my bioprene, I just throw 3lbs of weight between the wing and plate and I'm good to go.

Trying to understand those of you who are getting by without using weights. AL-80 is 4+ when empty so you should have around 8 lbs of positive buoyancy to neutralize.

There are also the bands and manifold to take into account.

 

[divezonescuba]

I have never dove anything but AL80s for doubles.

With a 3mm and plastic backplate, I need 16 pounds. So, if I used a conventional ss plate, I might be able to go to 10. My harness is an Ist with a lot of shoulder padding, but that probably would not account for more than another pound.

 

[rhwestfall]

great for warm water wet suit diving here in the St. Lawrence when it is 75 degrees at the surface as well as 140', or just a two tank recreational without the need to swap out.. Steel plate, stages, and manifold pretty much offset the buoyancy, and if needed, a v-weight.... I hate weight on my waist. YMMV.

 

[eelnoraa]

My double of choice for warm water dive, with wetsuit or light undergarment. As to weight comparison, a thermal single convertible valve weight about 1.5lb. A thermos 200bar valve+manifold weights about 5lb. So going from 2 single AL80 to doubled AL80, the valve/manifold adds about 2lb. Highland tank band set is about 4lb. So the +8lb from two single AL80 already become +2 with doubled up.

 

[decompression]

I've got a couple of sets of Al80's, mainly pool use but easy to add a V weight and SS plate when I need then for Open Water.

 

[DevonDiver]

As to weight comparison, a thermal single convertible valve weight about 1.5lb. A thermos 200bar valve+manifold weights about 5lb. So going from 2 single AL80 to doubled AL80, the valve/manifold adds about 2lb. Highland tank band set is about 4lb. So the +8lb from two single AL80 already become +2 with doubled up.

^this

When I sidemount 2x AL80, I'll carry 6lbs of lead, if using a 3mm suit. That accounts for neutral buoyancy at near-zero gas.

When back mounted, I don't need additional ballast, as the ali backplate, bands and manifold more than cover the 6lbs I need.

 

[Trace Malinowski]

Trying to understand those of you who are getting by without using weights. AL-80 is 4+ when empty so you should have around 8 lbs of positive buoyancy to neutralize.

I mostly use double AL80's and only need a steel backplate, bands, and regs for ballast. I don't use V-weights or anything even when diving dry.

Most tech divers have some extra body fat especially since we tend to start tech diving after our prime athletic years. I've been following an NFL style workout that creates a higher muscle to fat ratio even if I don't have 6 pack abs. For anyone who wants to get the lead off (and out of your @$$), I recommend heavy 5x5 weight training like Bill Starr's program. Combined with sprinting, runs < 5 miles, and swimming, you can get wicked strong, build explosive speed even in middle age, and be your own weightbelt.

5 sets of 5 reps splits the difference between starting strength and hypertrophy and seems to be a set/rep range that allows for concentrated and max efforts while keeping good form when performing squats, bench presses, bent rows, military presses, etc.

Most guys hit the gym and work on the upper body "show muscles," and go through the motions on the legs. Training the legs by lifting and sprinting puts mass on the biggest muscle real estate on the body and reduces the lead you need. Sprinting carves fat off quite well. I drink lots of Coca-Cola, Java Monsters, and eat pizza, chocolate, etc. If I dieted while following my fitness routine I'd probably have nice abs. I have a 34" waist, but if I cut out the junk I'd probably knock off 4 inches easily. But, the mass created by focusing on becoming Jason Whitten rather than a fitness model allows you to eat like a guy and not be floaty.

 

[boulderjohn]

I mostly use double AL80's and only need a steel backplate, bands, and regs for ballast. I don't use V-weights or anything even when diving dry.

I'm pretty similar. With a dry suit and steel BP in fresh water, I use a 5# soft V-weight pouch. I use that same BP and V-weight pouch with a 5mm wet suit in salt water.

 

[J-Vo]

With sidemount AL80s, I can nutralize my rig without tanks and regs knowing that an empty Luxfer AL80 with reg is about nuetrual. I feel more sucure knowing I am balanced without my tanks attached. Also, I can dive rental tanks anywhere and know my rig will work just fine.