MichaelMc
Working toward Cenotes
1) On your question. I dive tiny sidemount 2xAL40x3000psi or 2xLP50x2650psi aka 7L.
LP50 is more negative, but you can counteract that by shifting lead to the other side.
+ more air, + stays negative
- bit heavier on land, putting on/off, carrying about.
Not really the general recommendation for stages or deco over an AL40, as the 40 disappears as well.
AL40
- tail are positive even at start of dive, a bit annoying in water always floating up, really annoying turtlebacking as they become pontoons always in the way on the surface.
+ lighter to handle on land
+ less likely to sink rapidly to the depths if you drop trying to hand to the boat.
This is from sidemount perspective. I understand 40s 'disappear' as stages in backmount. I dove one that way once before I went sidemount, for some liftbag drills. Yes it disappears. I've spent more time with both now. I prefer the 50s. Though my experience is sidemount, not slinging one or even side-mounting one with a backmount rig, except that one time.
Though I understand tanks 3-4 sidemount (stages/deco) are better as AL40/72/80 all of which are light. So I really think you need to dive both and see. Maybe kludge up the difference by adding weight to the AL40, if you can not get a 7L. YMMV.
2) Being able to hold your stop is not the question. How much effort you expend just being in one spot in the water is the question. Or just moving from one spot to another 3m away. Get a video of you being still in the water with a ready reference so people can see where horizontal and vertical are. Not of you swimming slowly about. Of you still. Also of you still in one spot for 5 seconds, then moving 3m at the same depth, then still for 5 seconds. Shot from the side. Post it or compare it to various ones online as mentioned. Then you will get feedback on your trim and how much movement (of limbs/hands/fins) you have while not even moving (through the water).
A huge key to having low RMV in the water is being still, not moving, being relaxed, and making just the motions you need when you do move. Being horizontal helps that hugely by just pushing your shoulders and tank through the water when you move, not half your whole body. And its more fun then constantly kicking about.
3) Welcome, sorry if we or I've seemed a bit rough.
ETA: Doubles, OP would need huge tanks to do two dives per set. 2x10L to do one dive per set.
They are never still for very long, and do far more acrobatics than moving from point A to B, but this is what low effort in the water looks like.
Another, in backmount (doubles). It just looks stiffer with the arms out.
LP50 is more negative, but you can counteract that by shifting lead to the other side.
+ more air, + stays negative
- bit heavier on land, putting on/off, carrying about.
Not really the general recommendation for stages or deco over an AL40, as the 40 disappears as well.
AL40
- tail are positive even at start of dive, a bit annoying in water always floating up, really annoying turtlebacking as they become pontoons always in the way on the surface.
+ lighter to handle on land
+ less likely to sink rapidly to the depths if you drop trying to hand to the boat.
This is from sidemount perspective. I understand 40s 'disappear' as stages in backmount. I dove one that way once before I went sidemount, for some liftbag drills. Yes it disappears. I've spent more time with both now. I prefer the 50s. Though my experience is sidemount, not slinging one or even side-mounting one with a backmount rig, except that one time.
Though I understand tanks 3-4 sidemount (stages/deco) are better as AL40/72/80 all of which are light. So I really think you need to dive both and see. Maybe kludge up the difference by adding weight to the AL40, if you can not get a 7L. YMMV.
2) Being able to hold your stop is not the question. How much effort you expend just being in one spot in the water is the question. Or just moving from one spot to another 3m away. Get a video of you being still in the water with a ready reference so people can see where horizontal and vertical are. Not of you swimming slowly about. Of you still. Also of you still in one spot for 5 seconds, then moving 3m at the same depth, then still for 5 seconds. Shot from the side. Post it or compare it to various ones online as mentioned. Then you will get feedback on your trim and how much movement (of limbs/hands/fins) you have while not even moving (through the water).
A huge key to having low RMV in the water is being still, not moving, being relaxed, and making just the motions you need when you do move. Being horizontal helps that hugely by just pushing your shoulders and tank through the water when you move, not half your whole body. And its more fun then constantly kicking about.
3) Welcome, sorry if we or I've seemed a bit rough.
ETA: Doubles, OP would need huge tanks to do two dives per set. 2x10L to do one dive per set.
They are never still for very long, and do far more acrobatics than moving from point A to B, but this is what low effort in the water looks like.
Another, in backmount (doubles). It just looks stiffer with the arms out.
