Balancing wetsuit and steel tank bouyancies

[FishDiver]

I am putting together a matrix for balancing different size steel tanks with various wetsuit thickness for scuba travel. A common configuration for hundreds of my dives was a 5 mm suit, 8# plate, 2# lead and a steel 100 cf tank. I now have a 2# travel plate that I have used with a 3 mm suit and a 100 cf tank although it was a few pounds negative. I have also used my 8# plate with a 7 mm semi and a steel 120 cf with 8-10# of lead.

Aside from the "no steel with wetsuits dogma" are there any common configurations or rules of thumb for tank size vs suit thickness?

 

[Peter_C]

But you own a drysuit...

 

[FishDiver]

I have my buoyancy nailed in the DS. I am putting together sanity checks for travel gear configs.

 

[TSandM]

I travel with my dry suit . . . I don't know exactly what you are trying to do, but if you take three people in three different brands of 3 mil wetsuit, of different ages, and different sizes, their buoyancy could vary by several pounds.

 

[50Fathom]

I know a diver who is so morbidly obese, they can dive double HP120s in a 3mm wetsuit in freshwater and not be "unbalanced". Physiology definitely plays a role.

 

[FishDiver]

Good points all. I should have asked a more specific question set. Anyone know the average buoyancies of say a size large wetsuit in 3, 5, and 7 mm thickness? I can look up tank characteristics separately and make my own calculations. I own a heavy compressed neoprene drysuit that is a major hassle to fly with. Typically, I travel to the tropics where the temps and dive lengths dictate a wetsuit.

 

[rjack321]

You have everything you need math-wise right here:

5 mm suit, 8# plate, 2# lead and a steel 100 cf tank.

steel 100 is -1 empty so your 5mm suit = +9

I now have a 2# travel plate that I have used with a 3 mm suit and a 100 cf tank although it was a few pounds negative.

-1 for empty 100cf tank again plus -2 for light plate and still negative? 3mm suit on you is neutral or +1

I have also used my 8# plate with a 7 mm semi and a steel 120 cf with 8-10# of lead.

steel 120 is -2 empty plus -8 for plate and (average) -9 for lead = your 7mm suit on you is +19


so your...
3mm suit = neutral (for you, it floats but you sink a little)
5mm suit = +9
7mm suit = +19

Other suits and other divers are likely to reach different numbers. But you should be able to figure out how much lead you need for an AL80 tank and 5mm suit for instance.

 

[FishDiver]

You have everything you need math-wise right here:

steel 100 is -1 empty so your 5mm suit = +9

-1 for empty 100cf tank again plus -2 for light plate and still negative? 3mm suit on you is neutral or +1

steel 120 is -2 empty plus -8 for plate and (average) -9 for lead = your 7mm suit on you is +19


so your...
3mm suit = neutral (for you, it floats but you sink a little)
5mm suit = +9
7mm suit = +19

Other suits and other divers are likely to reach different numbers. But you should be able to figure out how much lead you need for an AL80 tank and 5mm suit for instance.

Brilliant! Thanks for doing my homework.