Help with Decision

[mick allein III]

I'm looking for other divers opinion about a possible equipment purchase.. I would appreciate pros and cons from divers who have done the diving with equipment described. Here's my background:

Closing on 50 years old, been diving about 4 years and have about 300 dives, all freshwater (Great Lakes and Quarries)? I love the shipwrecks. I may want to get into saltwater when my kids are gone and I have more time and money. Same with cave training. That won't happen for awhile either.

Certifications: OW, AOW, Deep, SAR, Drysuit, Rescue, and Solo

I would like to do some limited wreck penetration mostly at rec depths but maybe as deep as 150 so I need some technical/decompression.

Money/value/safety are all considerations:

1. Y valve with big steel tank 149cuft? Could I use my existing Knighthawk and Drysuit ? All I'd need would be the cylinder.

2. Doubles with BPW. I would need to purchase all of this.

3. Side mount. Need to purchase all of this.

Is there any configuration that would allow me the flexibility to switch between these.

Ok Divers, help me out give me the pros and cons. Thanks for all your help.




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[rx7diver]

I'm looking for other divers opinion about a possible equipment purchase.. I would appreciate pros and cons from divers who have done the diving with equipment described. Here's my background:

Closing on 50 years old, been diving about 4 years and have about 300 dives, all freshwater (Great Lakes and Quarries)? I love the shipwrecks. I may want to get into saltwater when my kids are gone and I have more time and money. Same with cave training. That won't happen for awhile either.

Certifications: OW, AOW, Deep, SAR, Drysuit, Rescue, and Solo

I would like to do some limited wreck penetration mostly at rec depths but maybe as deep as 150 so I need some technical/decompression.

Money/value/safety are all considerations:

1. Y valve with big steel tank 149cuft? Could I use my existing Knighthawk and Drysuit ? All I'd need would be the cylinder.

2. Doubles with BPW. I would need to purchase all of this.

3. Side mount. Need to purchase all of this.

Is there any configuration that would allow me the flexibility to switch between these.

Ok Divers, help me out give me the pros and cons. Thanks for all your help.




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mick allein III,

At one time I began ramping up my gear with the intention to learn and do Great Lakes tri-mix dives to 300 ffw. I purchased one OMS (Faber) LP 126, intending to purchase a second one when funds allowed. (I learned, shortly after the initial purchase, that my first child was on the way, and, so, never purchased the second tank.)

I dove the single OMS 126 a few times, with an "H" valve and with a "Y" valve, while slinging a Luxfer 40. These were drysuit dives.

I was NOT impressed. My double HP cylinders (PST 100's and 120's) were much more comfortable, much less unwieldy. Diving a single very large cylinder is not something I would ever again choose to do.

I never dove the single OMS 126 more than a few (six?) times. It sits forlorn in my basement. In fact, it has never been re-hydroed! (My firstborn was manufactured in 2001!)

EDIT: Something just occurred to me: I dove the single OMS (8" diameter) using a Halcyon SS doubles backplate and STA and Pioneer (30 lbs?) singles wing. It was the entire configuration that didn't agree with me. I now own one of Eric's (ZKY's) SS Freedom Plates. I occasionally dive this plate with a single HP 120 (7.25" diameter) and Halcyon Pioneer 27 singles wing. This is a completely different experience, extremely comfortable, recommended. Hmmm, maybe I should give the single OMS a try using my Freedom Plate...

Safe Diving,

rx7diver

 

[mick allein III]

Thanks for your response. That's the kind of info I'm looking for. It'll be interesting to hear the others response.


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[rx7diver]

Thanks for your response. That's the kind of info I'm looking for. It'll be interesting to hear the others response.


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I just edited my response. Might give a slightly different perspective.

 

[RJP]

A y-valve provides very little incremental benefit as far as I'm concerned. Redundant first stages merely offer redundant ACCESS to a single gas supply, while manifolded doubles provide redundant access to a redundant supply.

I'm closing in on 50 as well, and if I were buying all new stuff I'd consider side mount. However, with multiple BP/W rigs (I currently dive steel 119's) if I were going to change anything it would be a swap to double AL80s. (I'm actually considering this currently.) They aren't oppressively heavy and they trim out nicely both horizontally and laterally.

From a cost perspective, you could probably get a set of AL80 doubles for not much more than the cost of the one 149cf steel tank.

Since you mentioned wreck/cave... might as well bite the bullet now and replace the knighthawk with a BP/W or SM rig now. In for a penny, in for a pound...

 

[TSandM]

My husband and I, and a number of friends, dive HP 130s here on the West Coast, when a dive that requires that kind of gas supply is contemplated. They're not terribly big, although they are heavy. I have also known folks to double them up, and it wouldn't be unreasonable if you are contemplating dives in the sub-200-foot range (although going CCR is probably a more rational choice by the time you get that far).

I think most people would say that sidemount off dive boats is not ideal. Often, the gates are too narrow for a fully kitted-up diver, and the water conditions may not permit handing tanks down, or staging them in the water.

There is no setup I know of that will allow you to go from single tank to double or sidemount (unless you were diving single tank sidemount). Any setup that tries has made significant compromises in function for at least one of the setups. But if you are contemplating deep technical dives, the cost of a doubles wing will be the least of your worries.

 

[mick allein III]

Do you double the 130s or is this single mount? If single what do you do for redundancy?


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[rongoodman]

Given that you're doing mostly wreck diving, I would go with the back mounted doubles. They don't have to be unduly large and heavy. You could go with Al80s or LP85s and add a stage for the occasional dive where you wanted more gas, or to get two dives out of one fill of your doubles. They balance nicely, and would add a lot of redundancy. I like diving my sidemount rig in the caves, but I wouldn't take it on a boat. If finances are a big issue, used SS plates and doubles wings show up all the time here in the classifieds, regulator sets too.

 

[TSandM]

Mick, we dive the 130s as singles. We don't plan individual redundancy -- we have adopted a team diving approach, and your buddy is your spare gas. If I were single tank diving solo, I'd likely sling a 40 for redundancy, rather than put a Y or H valve on a single tank.

 

[rx7diver]

Y valve with big steel tank 149cuft?

Keep in mind, big steel tanks have physical characteristics that differ greatly and will likely feel quite different when dove as singles. Look at the Huron Scuba tank specification site (for example) and compare:

PST 120:
PST 104:

PST E8-149: 8" diameter, 29.4" length, 47.5#, -1.7# empty, 149 cu ft @ 3,442 psig.
PST E8-130: 8" diameter, 26.1" length, 43.0#, -1.0# empty, 130 cu ft @ 3,442 psig.

OMS 135: 8" diameter, 30.7" length, 47.0#, +0.8# empty, 131 cu ft @ 2640 psig. (174 cu ft @ 3,500 psig.)
OMS 125: 8" diameter, 29.0" length, 45.0#, +0.0# empty, 125 cu ft @ 2640 psig. (166 cu ft @ 3,500 psig.)
OMS 112: 8" diameter, 26.0" length, 41.0#, -1.0# empty, 112 cu ft @ 2640 psig. (148 cu ft @ 3,500 psig.)

PST 120: 7.25" diameter, 27.9" length, 39.2#, -1.3# empty, 123 cu ft @ 3,500 psig--for comparison. I don't regard this as a *big* steel tank. Subjectively, it doesn't feel *big*--unlike the others.

Safe Diving,

rx7diver

---------- Post added May 23rd, 2015 at 02:25 PM ----------

If I were single tank diving solo, I'd likely sling a 40 for redundancy, rather than put a Y or H valve on a single tank.

A lot of single-tank Great Lakes divers, because of the very cold fresh water, will use an 'H' valve or 'Y' valve and two complete regulators. They will run their BC off of one first stage and their drysuit off of the other first stage. A shutdown of either first stage will still leave a diver with some ability to power inflate something. Regardless of whether they sling a bailout bottle. (I actually prefer a 'Y' valve to an 'H'.)

Safe Diving,

rx7diver