advice on new doubles

[Arcaporale]

Hey, guys, I just noticed that this is in the "Cave Diving" forum.
Since I don't do caves and have no intention of doing so, my posts were, in my opinion, unsollicited, therefore I've deleted them.

Sorry, I'll try to pay better attention next time.

the K-aves Ain'g Gonna Happen

Looks as if I'm in the same boat as Kraken, I don't do caving either, yet. However that lady at the dive shop told me that these tanks would also be good for caving when I get there. It's just too bad there aren't any caves in California.

 

[H2Andy]

yeah, LP95's to 3500 psi will get you 125 cf per tank, 250cf total .... very nice

and cave shops fill to 3500 psi without blinking

 

[Mark Vlahos]

Andy, I like the higher pressure 3442 variants for cave fills. Sure I have 130's and they are too heavy for you, but when I get a fill of around 4100 or 4200 PSI I don't really sweat it that much. With a low pressure cylinder I would be a bit nervous with those same fills. Yeah, I know there are lots of divers who say the cylinders are the same, so just pump up those low pressure cylinders. Frankly they have a really good track record of getting cave fills with low pressure cylinders and no problems.

I went with a higher pressure cylinder and a 300 BAR manifold so I would not worry about cave fills. There is somthing to be said for peace of mind. Either the 119's or 120's would work well for you. Your low pressure 85 will give you about 111 cubic feet at 3442 PSI while the others will give you 8 or 9 more cubic feet. Frankly the difference is small and with cylinder matching you are really not talking about more than a 100 PSI difference on turn pressures so any of the cylinders you are looking at will only make a small difference.

To help with the weight you might do things like carry your reels and lights down to the water first along with a deco tank and hook the backup gear on in the water. It will require you to be more vigilant and will add some time, but it will make the walk to the water just that much easier. Your situatuion is unique so think outside the box for sloutions.

Enjoy,

Mark Vlahos

 

[mwpowell]

How about a rebreather? I have a buddy who dives an Optima, and it is a lot lighter than my double 130s. I'm getting one as soon as a win the lottery.

Keep in mind that if your buddy is diving smaller tanks, then gas matching rules will still constrain your dive to the smaller volume.

Mike

 

[limeyx]

Andy, I like the higher pressure 3442 variants for cave fills. Sure I have 130's and they are too heavy for you, but when I get a fill of around 4100 or 4200 PSI I don't really sweat it that much. With a low pressure cylinder I would be a bit nervous with those same fills. Yeah, I know there are lots of divers who say the cylinders are the same, so just pump up those low pressure cylinders. Frankly they have a really good track record of getting cave fills with low pressure cylinders and no problems.
...
Mark Vlahos

I've had a burst disk go on a set of HP-119's that were accidentally filled to approx 4000 psi(really -- the store fill guy forgot the compressor was on)

They sat in my garage for over a month just fine. Came home on a not especially hot day and found tanks strewn around the garage. Checked all the tanks, and everything was fine except one set of doubles at zero psi.

 

[Doc Intrepid]

bet it would have been exciting had you been in the garage when the disc blew!

 

[PerroneFord]

comment deleted

 

[Mike Edmonston]

bet it would have been exciting had you been in the garage when the disc blew!

I don't want to sound like a party pooper here , but there's a reason that these tanks have fill pressure limits.

your LP's can get a 10% overfill if they are + tanks. Please DO NOT take LP's to pressures higher than 3K. 3500 psi is really strapping a bomb to your back.

Now I'm sure that you'll get the " I do it all the time... " speech from other divers, and that's fine. just remember that it's your @ss on the line when you put them on. Let alone if they get hot from Car/truck/sun/trunk etc...

you have a few options, Go with the 100's. they are light and offer plenty of air. Remember to gas match to your team, and have fun .

Your other option is to do what I did. I got tired of carrying double 130's around, so I bought a DIVE RITE NOMAD. Now I sidemount everywhere, even open water. Plus I can bring my tanks to the water on a little dolly, yeah I know I'm a puss . But it works really well, specially at peacock or ginnie.

Good diving.

Cheers

Mike

 

[karstdvr]

just add stages when you need more gas.

A lot of drag,and can be tough on the cave

 

[Rainer]

I don't want to sound like a party pooper here , but there's a reason that these tanks have fill pressure limits.

your LP's can get a 10% overfill if they are + tanks. Please DO NOT take LP's to pressures higher than 3K. 3500 psi is really strapping a bomb to your back.

Now I'm sure that you'll get the " I do it all the time... " speech from other divers, and that's fine. just remember that it's your @ss on the line when you put them on. Let alone if they get hot from Car/truck/sun/trunk etc...

you have a few options, Go with the 100's. they are light and offer plenty of air. Remember to gas match to your team, and have fun .

Your other option is to do what I did. I got tired of carrying double 130's around, so I bought a DIVE RITE NOMAD. Now I sidemount everywhere, even open water. Plus I can bring my tanks to the water on a little dolly, yeah I know I'm a puss . But it works really well, specially at peacock or ginnie.

Good diving.

Cheers

Mike

Did you follow along with the other posts? Why would he want to go with the HP100s as you suggest when he's already getting his LP85s filled to 3500 (has been and likely will continue to do so) giving him MORE gas than your suggested 100s? What exactly does that solve other than robbing him of gas?