Steel 72 Doubles

[alwaingold]

That misses the compressibility of the wetsuit issue. You need to be able to be neutral at the end of the dive with empty tanks at 3m, this means you will be overweighted at the start of the dive (when you hit bottom) by the weight of the gas plus the buoyancy loss from your wetsuit. That's the weight you either have to swim up or ditch.

Indeed. I was referring to people spouting weights of various Al vs. steel tanks and how that contributed to the rig being balanced. My point is that as far as the tanks are concerned, it is the weight of the gas in them that counts. AND, if the weight of the gas in the tanks is too heavy (which 20 pounds likely is), you aren't going to get a balanced rig, wetsuit compressibility or not.

 

[Rainer]

There should not be a need to drop weights at depth.

If that were the case, stages and deco bottles wouldn't be ditchable. They are. I assure you, any T2 diver is heavy. Without ditching, you can't do these dives in a "balanced rig". Or does "weights" not include such for you?

 

[amascuba]

If that were the case, stages and deco bottles wouldn't be ditchable. They are. I assure you, any T2 diver is heavy. Without ditching, you can't do these dives in a "balanced rig". Or does "weights" not include such for you?

Indeed, but the process of dropping stage bottles is a lot simpler than dropping a weight belt thats under your crotch strap.

 

[Rainer]

You think? I'm sure I could get my belt off and have the crotch strap redone in the time it took me to ditch a couple of stages.

 

[SparticleBrane]

That's why you put the weight belt over the crotch strap...

 

[Rainer]

That's why you put the weight belt over the crotch strap...

Guess that depends if you consider your weight belt ditchable. For the rigs I dive, it isn't. It's just a means of adding cheap ballast. If it slips or the buckle breaks, I want it to get hung up on the crotch strap.

 

[lamont]

If that were the case, stages and deco bottles wouldn't be ditchable. They are. I assure you, any T2 diver is heavy. Without ditching, you can't do these dives in a "balanced rig". Or does "weights" not include such for you?

Better solution for a T2 or T3 diver is to point your scooter up and pull the trigger, rather than trying to ditch anything.

 

[lamont]

Indeed. I was referring to people spouting weights of various Al vs. steel tanks and how that contributed to the rig being balanced. My point is that as far as the tanks are concerned, it is the weight of the gas in them that counts. AND, if the weight of the gas in the tanks is too heavy (which 20 pounds likely is), you aren't going to get a balanced rig, wetsuit compressibility or not.

Double Al80s with an 8# v-weight vs. double X7-100s filled to 2640 should be identical.

If you move the 8# v-weight to ditchable, that would be an important difference that would allow you to drop some weight if you have a problem at the beginning of the dive with being overweighted and with wetsuit compression. However, if you ditch too much you won't be able to hold your stops in open water (and may get pinned to the ceiling in a cave), so this isn't a very good solution.

Very thick wetsuits with a lot of compression are also probably not DIR at all because of how hard it is to make them balanced. Anything thicker than a 5mm probably needs to be replaced with a drysuit.

 

[ONFLOAT SCUBA]

I happen to know one GUE instructor that teaches all of his Fundies classes and does his less than T1 dives in a set of medium pressure Dbl 72's. So the double 80's thing as a minimum is not true.

Plus, I love my dbl 72's for all my simple dives.

blasphemy

 

[onfloat]

I didn't say anything about 25/25.