LP95 or even LP108 for Sidemount Diving?

[Caissy]

Worth noting this. Completely different style in Mexico compared to what's needed for our heavy tanks back home.

I'm well aware of that, but thanks @northernone and @tbone1004 for the head's up!

 

[rjack321]

In cold water for a 200ft SM dive... You end up with a lot of lead, a suit gas bottle, 2 deco bottles, a light canister, and a possibly a drysuit heater canister so you really start to wonder why you aren't using the real estate on your back for some of that stuff. Especially if you are jumping off a boat and just going down to a wreck and back up. In a cave you can at least drop the deco bottles and get sort of small, but a suit bottle, light & heater canisters all conspire against you - they end up shoving tanks out or down in ways you dont want, or they're piled up on your butt anyway. In open water you are better off using your back and right hip for tanks, lights, and suit heat.

I'm sure it will be fun, but Mexico will not prepare you for Canadian SM trimix diving at all

 

[Caissy]

In cold water for a 200ft SM dive... You end up with a lot of lead, a suit gas bottle, 2 deco bottles, a light canister, and a possibly a drysuit heater canister so you really start to wonder why you aren't using the real estate on your back for some of that stuff. Especially if you are jumping off a boat and just going down to a wreck and back up. In a cave you can at least drop the deco bottles and get sort of small, but a suit bottle, light & heater canisters all conspire against you - they end up shoving tanks out or down in ways you dont want, or they're piled up on your butt anyway. In open water you are better off using your back and right hip for tanks, lights, and suit heat.

I'm sure it will be fun, but Mexico will not prepare you for Canadian SM trimix diving at all

I'm obviously already aware of everything you're saying, and if we look at the best configuration for this kind of dive, SM isn't number 1. However, I'm moving to a rebreather in a year from now, so I'm not interested in investing any money in doubles at the moment. My goal is to gain as much experience as possible in SM so I can be confortable cave diving with my wife in Mexico about once a year. And since she's not interested in CCR, I want to dive the same configuration as her...

So to add to your point, doubles aren't the best configuration once you start using expensive helium, CCR is and that's where I'm going soon. But meanwhile, I'm interested in more gas in the configuration I'm currently diving with, knowing that 20-25 min bottom time is getting close the max I'll be able to do in SM at 200 feet... It's all good experience!

 

[tbone1004]

@Caissy for OW diving, just add stages on a leash. With He in them they disappear quite easily and you'll like 85's better for CCR dilout gas unless you're doing big deep caves. If you're going to CCR soon ish, I'd forego the second set of steels unless the mixes are going to change regularly and use stage bottles

 

[Caissy]

@Caissy for OW diving, just add stages on a leash. With He in them they disappear quite easily and you'll like 85's better for CCR dilout gas unless you're doing big deep caves. If you're going to CCR soon ish, I'd forego the second set of steels unless the mixes are going to change regularly and use stage bottles

Great advice... I'll will consider this approach. Thanks a lot...!

 

[rjack321]

@Caissy for OW diving, just add stages on a leash. With He in them they disappear quite easily and you'll like 85's better for CCR dilout gas unless you're doing big deep caves. If you're going to CCR soon ish, I'd forego the second set of steels unless the mixes are going to change regularly and use stage bottles

Most of us can do 180ft in cold water on a set of 85s fairly easily and 200ft is your SAC is good. The SM problem isn't really the bottom gas, its where to efficiently put all the deco gases and suit bottles. And being able to not be the slowest diver getting on and off the boat - with drygloves.
Personally in his circumstances would dive backmount 95s/119s at home with an 80 of 50% and a 40 of O2 and on wrecks etc and with the dry gloves and a suit heater. Save the SM for mexico for caves with your spouse.

The 85s are overkill BO for most CCR dives. 2x 80s is plenty of gas for up to 30mins at 210ish. You have to start nudging up against 250ft before the 80 of 15/55 starts being skimpy. Which is the same time the 80 of 50% is inadequate as well. But 3 bottle CCR dives are far in his future and not something to plan for now.

You don't need to dive one configuration all the time. Look at what your local divers are doing and why, a lot of the suggestions you are getting here are from cave divers from FL. That's not how Great Lakes wreck divers are doing things and you are likely to get a lot of flack from your buddies and charter operators for going against the grain needlessly.

 

[Caissy]

@rjack321 You obviously have a lot more experience than I have and I respect/value your comments!

I cannot dive on some charters due to the fact that I'm doing sidemount and on the ones that I'm allowed, I need to stand up with my two LP85s and my AL40 and try to walk on the boat the best I can before jumping. For charters, sidemount is the worse configuration! In the water, I have less gas than my friends with double 130s and getting out of the water is also somewhat more difficult...

However, I was able to get some nice experience with thick double gloves in sidemount before going to do my cave diving course in a few weeks, where I will not be wearing any gloves (everything is soooo much easier bare hands!!!). So although I totally agree that I didn't use the best configuration for cold water wreck diving, I nevertheless gain the experience I was looking for this year.

If you were me, would you invest time and money in doubles just for a season, knowing that I'll invest a ton of time and money in a CCR soon? I certainly don't feel like it... Instead, I want to push my sidemount configuration and learn how I can go deeper and/or stay longer under water. So even if it's less than ideal, it will be good experience for me... So staging cylinders is one way to push the sidemount configuration (unthinkable on charters) and using bigger cylinders is another (hence the topic of this thread), I'm trying to see what would allow me to reach my goals next summer without breaking the bank...

BTW, I have my own boat so I can take my time if I dive from it!

 

[tbone1004]

@rjack321 ding ding,
also of note, which I know you know but for @Caissy
I dive doubles in OW unless I have a very specific need for sidemount *rare*. I think doubles are better for that job so sidemount only comes out if the dive requires it.

If diving my CCR in OW, it is in a rack GUE style with LP50's for dilout. That's a lot of gas and more than enough to get you very deep. My rig with a Meg weighs about as much as a set of PST104's and has a 3l of O2, 3l of suit inflation gas, and a pair of LP50's for dil/bailout. Fully self contained except for deco gases. It's awesome and I wish that @cool_hardware52 kept making those racks because they're amazing.

Sidemount is for cave diving and if I dive doubles in a cave it's extenuating circumstances.

Can I get on and off a boat in sidemount? Of course, but it will never be as fast as doubles and I don't think it's as ideal as backmount, my opinion. Single tank sidemount is the tits though for warm water stuff.

 

[J-Vo]

... knowing that 20-25 min bottom time is getting close the max I'll be able to do in SM at 200 feet... It's all good experience!

I'll be doing 30 minutes at 200' with 85s this weekend. No stage required for that one and only 40s for deco. Makes for a pretty nice dive.

 

[Caissy]

I'll be doing 30 minutes at 200' with 85s this weekend. No stage required for that one and only 40s for deco. Makes for a pretty nice dive.

What would be your total gas consumption for your 30 min bottom time + deco if you get a major failure with your 40? For what I can see, even if your SAC is 0.40, there's no way you'll have enough gas if you lose your deco gas at the end of your bottom time... Your buddy can obviously help you, but that's not the point here...