Researching to buy gear - Cavern recs?

Hello all-

I'm in the market for a gear purchase, and want to get as many opinions as possible before plunking down the $$$. I've read just about everything gear-related on the board so far, but I haven't seen recommendations for a diver who plans to go no further than cavern training. If, after years & years of experience, I decide to progress to cave, I'll worry about my equipment then (and be able to afford a new setup if needed). For now, realistically, the majority of my diving will likely still by inland quarry & tropical vacation, with (hopefully) a yearly trip to Florida caverns or the Yucatan (I had my cavern appetite stimulated after my first guided tour of the Chac Mool cenote a few months ago).

So, recommendations for (1) BC types (BP/wings not necessarily a huge benefit with single-tank diving only, correct?); (2) regulator (leaning toward the Mk25-S600, but perhaps the G250 is a bit better for the ability to remove the faceplate underwater?? Also tempted by Atomic, but nervous that it may be more difficult to service if I move or need service outside the country); (3) 7' hose seems recommended even w/ cavern-only divers, correct?; (4) computer (thinking about a Dive Rite NiTek Plus).

DIR status is not that important to me, as I'm admittedly not well-versed in the details of DIR philosophy (although I do have JJ's book on order so I can familiarize myself, and I *would* be interested in taking the DIR-F course to further my diving education).

Thanks,
Jim

jpsmith once bubbled...
Hello all-

I'm in the market for a gear purchase, and want to get as many opinions as possible before plunking down the $$$. I've read just about everything gear-related on the board so far, but I haven't seen recommendations for a diver who plans to go no further than cavern training. If, after years & years of experience, I decide to progress to cave, I'll worry about my equipment then (and be able to afford a new setup if needed). For now, realistically, the majority of my diving will likely still by inland quarry & tropical vacation, with (hopefully) a yearly trip to Florida caverns or the Yucatan (I had my cavern appetite stimulated after my first guided tour of the Chac Mool cenote a few months ago).

So, recommendations for (1) BC types (BP/wings not necessarily a huge benefit with single-tank diving only, correct?);

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Incorrect. I'm strictly a rec diver and I feel the bp/wing setup is far, far superior to a traditional BC. There are lots of reasons, chief among them streamlining, simplicity, ruggedness, comfort, and, most of all, stability.

jpsmith once bubbled...
(2) regulator (leaning toward the Mk25-S600, but perhaps the G250 is a bit better for the ability to remove the faceplate underwater?? Also tempted by Atomic, but nervous that it may be more difficult to service if I move or need service outside the country);

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I don't think you'll need to worry much about removing the face plate underwater. When you have an hour of deco to do, and the reg on your O2 bottle is jammed.. then you'd care. But in OW if anything happens switch to your backup and egress. Also consider Apeks.. high quality Apeks regs can be bought from DiveInn for as little as $250.

jpsmith once bubbled...
(3) 7' hose seems recommended even w/ cavern-only divers, correct?;

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Correct. You can certainly get many benefits of the long hose diving OW rec stuff only.

jpsmith once bubbled...
(4) computer (thinking about a Dive Rite NiTek Plus).

DIR status is not that important to me, as I'm admittedly not well-versed in the details of DIR philosophy (although I do have JJ's book on order so I can familiarize myself, and I *would* be interested in taking the DIR-F course to further my diving education).

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Good philosophy. Get the computer (just about anything will do.. Suunto's seem popular because of the gauge mode option), but be smart and plan your dives and don't run your computer down into deco. It's a tool, it's not there to tell you how to dive.

...On everything. Ditto.

By the way, I wrote a lengthy article on BC's and why I personally chose a bp/wing setup, even though I dive singles. It can be found at http://www.bftwave.net/lcscuba/homebc.html

Also, I believe that a lot of your questions will be addressed in that DIR-F book that you have.

Others have given you some details, let me give you some philosophy…

Fundamentally, technical diving is no different than recreational diving in any way, except for technical diving you need more reliable (read: better) equipment and you need to be a better diver, which is assisted also by better equipment.

So better diver and better equipment… Sounds like that would work well for recreational diving as well, don’t you think? It does.

Note that you may not need all the technical equipment like reels and a canister light, but this is equipment deletion, NOT substitution. So you may delete the canister light, but you don’t substitute a jacket BC for a backplate and wing. You may delete a reel and spool but you don’t substitute a short hose and stuffed octo for a long hose and bungeed backup.

Ok, I guess you do substitute a single cylinder for doubles, but because that’s behind you, your interface to your equipment doesn’t change, so that’s not really a substitution.

Real “Technical” gear (especially the BP & Wing) is more reliable, and assists you in being a better diver, which is COMPLETELY applicable to recreational diving.

Please note I’m talking real technical gear. Fashion tech, which is for example any BC festooned with D rings, is NOT real technical gear and should be avoided.

Lastly the cheapest gear is gear that you buy only once. Go now with a BP, and if you decide to go full cave later on, you don’t have to replace the BP (you will have to buy a new wing, for a fraction of the cost of getting a new BC device). And even if you never go cave, you’ll have excellent, reliable gear that will assist and improve your diving.

Roak

roakey once bubbled...
Note that you may not need all the technical equipment like reels and a canister light, but this is equipment deletion, NOT substitution. So you may delete the canister light, but you don’t substitute a jacket BC for a backplate and wing. You may delete a reel and spool but you don’t substitute a short hose and stuffed octo for a long hose and bungeed backup.

Ok, I guess you do substitute a single cylinder for doubles, but because that’s behind you, your interface to your equipment doesn’t change, so that’s not really a substitution.

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This is a very good point I haven't yet heard articulated, roak. I'd been following the rec.scuba conversation about switching to a shorter primary hose in open water, and figured that that's not optimal, but I couldn't really put into words the real underlying concept that violates.

I recommend the G250 not because of faceplate removal, but because I believe it's the best reg they make. I think the larger diaphram must make it easier breathing. I've had virtually every reg that scubapro makes, and I've sold them all for 250's. The Mk25 is fine too, but I like the Mk 16 better. It has no swivel, which is at least theoretically a failure point, especially if the swivel retaining bolt is overtightened even once. The Mk16 is more compact too. You'll be happy with either the Mk16 or Mk25, in my opinion.

Also, as Roak mentioned, the backplate setup is the way to go even for rec diving. Options are available. I've settled on Halcyon wings which seem to me to be built better. I've had several backplates and brand doesn't seem to matter much except for appearance. Pay attention to what sort of tanks you'll be using. For example, with heavy steel doubles, you'll need an aluminum backplate; for light tanks you'll need a steel backplate.

Campana once bubbled...
The Mk25 is fine too, but I like the Mk 16 better. It has no swivel, which is at least theoretically a failure point, especially if the swivel retaining bolt is overtightened even once. The Mk16 is more compact too. You'll be happy with either the Mk16 or Mk25, in my opinion.

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The swivel concern is not in any way shape or form a new or recent issue. It takes me back about 25 years and defintiely predated DIR.

I agree the swivel on the Mk 25 is a theoretical failure point. The same argument was made when SP introduced the MK10, as the swivel was a major change compared to the then standard of bullet proof regs - the Mk 5. SP even came out with the Mk 9, a Mk 10 without the swivel to calm those divers who feared the dreaded swivel and it's potential for failure.

However, I have never heard of a MK 10, MK 15, Mk 20 or Mk 25 swivel failing. It is a theoretical possibility, but is in no way an operational concern. The piston design is very simple and if you want to talk theoretical failure points, don't even think about comparing any of those swivel equipped regs it to a diaphragm reg with its greater parts count, greater number of moving parts and seals all of which are theoretically subject to failure.

The Mk 10 was bullet proof, had one moving part and two O-rings subject to wear through friction. Really simple, utterly reliable. Mk 20 and 25 are generally similar but use bushings to make replacing the o-ring sealing the piston shaft easier. The bushings can theoretically fail but this is again not an operational issue with regular service.

I agree completely on the G250 comments. Small size is a great marketing gimmick but I have never seen the practical advantage of this in water. The benefits of a larger diaphragm are hard to beat.

The performance numbers on regs are often misleading and "ease of breathing" is often an average of the suction required to get the reg flowing combined with the over inflation that many regs will do. The result is a very low "ease of breathing number", but it does not feel natural. Positive pressure is not natural nor in my opinion comfortable and many if not most divers detune the viva effect to eliminate much of this forced air effect.

In my opinion the G250, it's predecessor the Balanced Adjustable, and the D400 (the older ones with the metal orifice) were the best "feeling" and most natural breathing high performance second stages Scubapro ever made.

If you are looking for superb performance and reliability and can find a good used MK 10 G250 or Mk 10 D400, you should give them serious consideration. Both have removable covers. If you don't care about the removeable cover, a Balanced Adjustable offers the same breathing performance of the G250 without the viva adjustment and has a stronger and more durable metal case.

I have not tried a Mk16 yet but I have a Mk25/S600/R380 and to tell you the truth I am none too impressed. Its smooth but its really doesn't live up to my expectations. I will say it breathes as well at 100 feet as it does at 10. Personally if I had to do over again I would get an Atomic, probably the Z1. I fortunately have no problem getting them serviced in the Cincinnati area since there are atleast 3 Atomic dealers in town. If you decide to go Scuba Pro I would go with the Mk16 first stage because it is cheaper and sealed.

I would also suggest that you research what the various dive certification agencies recommend and take with a grain of salt any agency claiming their way is the only "true" way to dive

SeaJay once bubbled...
...On everything. Ditto.

By the way, I wrote a lengthy article on BC's and why I personally chose a bp/wing setup, even though I dive singles. It can be found at http://www.bftwave.net/lcscuba/homebc.html

Also, I believe that a lot of your questions will be addressed in that DIR-F book that you have.

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I see a lot of thought went into your article. One difference of opinion I have concerns actual experience. While you show the bladder of a back inflate BC evenly full, I know from personal experience that a Zeagle ranger will fill in areas. If you add air in a slightly head down attitude, the air will migrate to the "bottom" of the bladder, near your waist. This will assist in easily maintaning a head down or horizontal position. You can even go slightly head down, fill some, and go SLIGHTLY head up and add some more to get virtual trim pockets (maybe the ranger has designed trim pockets, I don't know) of air for a neutral buoyancy distribution at horizontal or slightly head down. It took a bit of practice in the beginning, but now it's more or less automatic. (Or it was until I stayed dry (destitute!) for the last 3 years!)

That said, I have an intro certification but can't say I did a great deal of research into equipment, at least concerning BC vs BP/wing setups. I simply got a reasonable BC that would be serviceable for moderately technical diving situations.