Scooter gas management

[FW]

I left out one important option, do a dive like that with one, or more buddies. All that spare gas and scooters really helps.

[inverted_bear]

Using only stages works great until you need to swim after scootering. What happens when you are scootering to a nomount restriction and want to pass it? It's a real b*tch to bring the stage through too.

You should calculate how much you need to swim out from max p' (unless you have a tow scoot) * a safety margin. Ideally, you keep as much of that with you as possible, and you drop stages as far into the system as possible.

However, sticking to a hard rule like "don't touch backgas ever" is a recipe to bring ridiculously large reserves for small dives and relatively tiny reserves for big dives.

[rddvet]

Deleted my post.

[rddvet]

However, sticking to a hard rule like "don't touch backgas ever" is a recipe to bring ridiculously large reserves for small dives and relatively tiny reserves for big dives.

Agreed. Prior to the class I felt having a big safety margin of all that backgas was ultra conservative. As I started to realize the distance one could get back in the cave on a scooter I saw some holes.

Good discussion thus far.




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[LiteHedded]

Edd's right that there is no rule. Think about the specific dive you want to do and add gas/scooters till you feel comfy.

Swimming out isn't always going to be an option

[Nitrogenius]

while there is a lot of merit to trying to staying on the stage(s) especially when it is a combined scooter/swim dive then I also believe in the merit of KISS too and also try to eliminiate as many potential thought process/ calc failures as possible if the planning starts to get complex.
Generally for scootering the shallow no flow caves in mex I found that rule of sixths overall gas is working quite well, contingent on mainly not so large tunnels, so no next generation scooter high speed chases but merely making the 'old school' 150' per min upon penetration as well as still not full relaxed SAC in trigger due to maneuvering the scooter etc., so somewhat comparable to regular swimming SAC.
Given that when we are doing combined scooter/swim dives it is easy. Go sixth on the stage(s) on the trigger. Drop scooter and stages upon reaching sixth( or your planned swim start point) go swmming upon your swimming gas rules you are comfortable with (essentially treating the scooter with the stage(s) as your 'exit'.

This will ensure that even if you had the scooter fail when you return you still can swim all the way. Also make an estimate of time if slightly deeper of your max bottom time in a swim out event and plan deco gas/deco reserve on such basis.

If you happen to use two stages it makes sense to only breathe one stage to thirds on the way in and not touch the second to save a switch while scootering. on the way out upon multiple dives this also helps fill logistics. just keep the full stage untouched and use it the next day/dive.

For scooter only since in Mex it is usually 80s only with 2 stages just smoothely scooter to thirds or go to two thirds on the way in on one stage and use the other on the way out to save switches..

[diver42]

Here's one way to think about it: To add safety margins on a long scooter dive, you can add gas (stages), or you can add scooters. Some dives are just too long to swim back from on open circuit—you could never carry enough extra stages. (Presumably you could do a series of dives and add safeties as you go, but I'm not sure this is practical in most situations.)

Assume you're doing a dive that requires the burntime of one scooter. If both members of a two-person team each tow a scooter, and everybody carries a little extra gas, you can lose three scooters and still make it back out. If this is your plan, adding non-trigger time is a matter of adding gas as if you're on a swim dive.