mk2evo/r195 for deep dive pony tank

[landlockeddivingdoc]

Hello all.

Going to be taking a deep class (130ft, temp >50F) in a few weeks. I'm planning to set up the pony (AL30) on my own instead of renting, as I can see a need in the future.

I had recently upgraded my primary regs to a mk17evo/g260 in preparation for deeper/more demanding diving, and so now have a spare mk2evo/r195 DIN.

Question: would these regs be appropriate for the pony set going to depth? It's my understanding that the concerns for unbalanced regs at depth are performance with the drop in IP between a full and emptyish tank, and the overall gas flow which could be limited at depth in such a situation as a buddy breathing on an octo at the same time. If that's the case, it would seem that they would be mitigated since the tank would remain at the same full psi until used, if I have to use it the dive's over and I'll be quickly headed to the surface, and only one diver would be breathing on the reg.

Is my line of thinking appropriate here? Would this be an ok reg set for the pony at those max depth and temperature conditions? I an understand the argument for getting the best/easiest breathing regulators you can in order to remove a bit of effort or worry during an emergency situation, but on the other hand if the bulletproof oldies are safe and reasonable to use, I could use the savings.

 

[OrcasC205]

The Mk2 and R195 should do fine for that -- they are both EN250 rated so they will have adequate airflow even at deeper depths and, as you mentioned, this will be strictly for bailout, so there should never be two divers breathing off it simultaneously.

I would be more concerned with the AL30 being enough gas for an issue at 130 ft. You are looking at an average ATA of 2.5 atmospheres on the ascent and at a higher breathing rate due to the emergency, that doesn't give you a ton of time on the ascent to even shoot an SMB or handle any deco obligation incurred as you troubleshot the problem.

 

[landlockeddivingdoc]

Thank you for your answer. I'm much more comfortable utilizing the regs after hearing it.

I agree with the concerns about the duration of gas supply. My SAC is still improving, but can still tip the needle at ~0.6CFM based on my Teric data. Assuming a stress increase of 2-4x and an average of 2.5Atm, the AL30 is marginal. Eventually I'd like to move on to doubles, but for the time being I've got to figure out the best balance of what I might need and practicality (I'm pretty short, so slinging can sometimes be awkward). Hopefully it would be able to get me to a drop tank.

 

[OrcasC205]

Thank you for your answer. I'm much more comfortable utilizing the regs after hearing it.

I agree with the concerns about the duration of gas supply. My SAC is still improving, but can still tip the needle at ~0.6CFM based on my Teric data. Assuming a stress increase of 2-4x and an average of 2.5Atm, the AL30 is marginal. Eventually I'd like to move on to doubles, but for the time being I've got to figure out the best balance of what I might need and practicality (I'm pretty short, so slinging can sometimes be awkward). Hopefully it would be able to get me to a drop tank.

Yeah, and unless you are diving solo, you should be able to rely on your buddies, too. Just food for thought as you are looking at gas requirements at deeper depths.

 

[Whitrzac]

Mk2s are horrible. Lmk where you see any din ones for sale

 

[RyanT]

MK2/R195 will work just fine for your application.

 

[Nemrod]

I know that I am a contrarian and to some extent have become fatigued with the over hype of regulators as if somehow a $2500 regulator set is a must have nowadays. So, putting my money where my mouth is I upgraded myself to a Mark 2 Evo and G250 from my Mark 17 Evo and G260s.

The Mark 2 Evo has had several notable improvements over the Mark 2, most notably a replaceable orifice and larger piston and larger volcano orifice and outwardly smaller case. Here is part of the reason I get flummoxed with these regulators that can flow 6000+ LPM:



Yeah, that 6000 LPM must go through all of that before it ever gets to the regulator first or second stage. And at that, the Mark 2 Evo has twice the open flow rate of the AL Legend first stage, 1500 LPM vs 3000 LPM for the Mark 2 Evo (@3000 psi).

I would rather see you with a G250 mated up to that Mark 2, but yes, you should be fine with the R195. A balanced second stage (like a G250) will perform better with an unbalanced first stage at low supply pressures, should you ever suck that pony down to 500 psi .

 

[landlockeddivingdoc]

So, putting my money where my mouth is I upgraded myself to a Mark 2 Evo and G250 from my Mark 17 Evo and g260.

I might be able to get a recently serviced g250 for cheap, and if so I'll certainly run it instead of the r195. If I might ask, though, why did you change from the 260 to the 250?

 

[PEDiver]

I might be able to get a recently serviced g250 for cheap, and if so I'll certainly run it instead of the r195.

I have 7 G250s and I’m always on the hunt for another one. They are one of the best regulators ever made IMO.

 

[andrespp]

I am a rebreather diver, and have been using MK2+R190s for my bailout tanks for many years. Meanwhile fortunately I had never to bailout, in some ocassions I tested my bailout tanks at 60-70 meters deep, and they work wonderfully, however it must be noticed that the tanks were full charged at 200 bars and there was some helium on the mix. MK2s, with its simple design, will take a lot of abuse before malfunctioning, and reliability is a big factor here.

However, IMO the AL30 in a situation that you really need to use it as bailout is way too small.