Trimix Open Water Rig Critique

[TheRedHead]

Suit compression hasn't been much of an issue for me diving steel with a 3 mm suit. It becomes an issue in cooler water with thicker neoprene. But it is very common in tropical waters to dive steel with 3mm or thinner suits.

 

[Scubydoo713]

I'm not as experienced as a lot of the people who have posted on this thread, but a couple of things have concerned me about this rig. If my calculations are correct, you're carrying 380 c/f of gas, in steel tanks, that is attached to you from the get go, as opposed to sling bottles, that can be attached after you enter the water. I normally use steel 95's doubled up, down to about 220', and 104's below that, with either al 40's or al 80's as deco bottles. I do almost all my deep diving off my own boat and can't imagine trying to get back on board, especially in 4' waves, carrying that much weight. You've got to be carrying 200+ lbs. It would seem to me that you would need to spend all your spare time in the gym, just to keep enough muscle mass to handle the weight or you would need a hoist to haul you back on board. Perhaps I didn't completely understand the setup, but it seems too complicated for my liking. Also, as posted by TSANDM, 32% nitrox makes a poor deco gas.

 

[theskull]

. . . The backup bladder is not DIR as it adds another element of complication and failure. A drysuit would be used as redundant source of buoyancy and a lift bag would be a third source. . .

A backup bladder adds an element of complication and failure, but a drysuit does not??

I'm not following that logic. This is assuming that a drysuit is not already required, as in warm water reef diving, which I believe is the scenario here.

How is a bladder more complicated and prone to failure than a drysuit?

theskull

 

[drperi1]

can't completely make sense of the logic re: the drysuit is not a backup bladder, but at the same time, double bladders aren't necesary w/ a drysuit. think dherbman is right, though. the wetsuit compresses under pressure, & therefore adds negative weight @ depth (i think- sb correct me if i've messed up here), whereas the drysuit adds either positive buoyancy or neutral bouyancy @ depth, & positive bouyancy on ascent.

will be talking to an expert next week; see what he says, & hopefully can make this less confusing for all of us who don't quite get it. 2 wings attached to a backplate are no longer recommended due to possible entanglement (line caught b/w bladders) so when diving overhead conditions (any cond'n where you can't just go up) a dual-bladder wing (2 bladders w/in 1 wing, w/ 2 lp hoses) is recommended w/ a wetsuit. i bought a dual-bladder rec wing from diverite, which works for my size/gas needs, but there are a lot of other really good choices.

I have had a drysuit fail during an overhead dive, &, as mentioned by dherbman, used my lift bag (i like the self-sealing ones; that way, i don't have to weight the bag to stay full @ the surface) to increase my stability @ deco stops.

Hope this helps, & doesn't confuse the issue more
dive safe & live well