Re: OMS- why is it so bad?

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Posted by Kendall Raine on May 14, 2002 at 11:54:50:

In Reply to: OMS- why is it so bad? posted by Eric S on May 13, 2002 at 21:03:30:


I'll try to bat clean-up on why much of the OMS stuff isn't what you want. FTR, this isn't about "my brand" or any other such nonsense. It's about what is designed in a sensible and well thought-out manner. That is consistent with the "less is more" philosophy of minimalism.

1. Backplate. This is a piece of metal, in the OMS case SS. Nothing wrong with it that rerigging wouldn't cure.

2. Harness. This is distinct from the backplate. The way OMS rigs the webbing is poorly designed. First, the webbing is not one piece of material. It is sewn in multiple places which is a theoretical failure point. Second, the webbing has plastic quick releases in it. This is a non-theoretical failure point and is not only unnecessary but very bad. Third, the webbing has a chest strap which is worse than useless. Fourth, the webbing has too many d rings to be useful and the d rings are rigid. The rigid chest rings are especially stupid-try backing out of a tight restriction with recurve rigid d rings. They can ratchet you into a hole.
Fifth, the crotch strap is secured by a plastic quick release-another real falire point. Sixth, the buckle is plastic. Dumb. It can break and the lever can come out with torque.

3. The IQ pack is a complete mess. It has all the flaws of the harness above plus hard mounted d rings which are unnessary and useless.

4. The wings get the most criticism, next to the slobwinder, and with good reason. 85 lbs of lift is way too much if you're diving a properly balance rig. To compensate for having too big a bag and too much drag, OMS wraps the wing in bungie. They thereby turn a bad dream into a nightmare. The only real service performed by the bungie is to insure that any leak will result in total evacuation of the wing and complete loss of buoyancy. Recognizing this, they created the double bag wing. This converts the nightmare into a full-on psychotic episode. The double bag adds more drag to the wing necessitating tighter bungies and another inflator hose. Having another inflator now means you have an extra inflator hose and an extra LP hose and inflator-additional failure points. The inflator hoses are too long creating a major danglie. This compounding of mistakes looks cool to the neophyte but is a functional abortion.

5. The phantom light is terrible. The canister is nice and slim, but has two screw on ends creating an extra leak point. The canister also hard mounts on the backplate which means you can't take it off U/W. That's dangerous inasmuch as you can't clear an entanglement or extract yourself if it keys you into a hole. The canister uses captured o rings which can trap expanding gas in the event of a hydrogen explosion. There is also no way to see whether the o rings is making a proper connection. The light head is massive-good for smashing portholes but otherwise way too bulky. Th mini is fixed beam, another design flaw. The HID version with the two canisters is beyond ridiculous.

6. The manifold crossover needs to be screwed down tight (I think)-can't spin-and the knobs are hard plastic which increases the likelihood of a knob impact breakoff.

7. Stage bottle hardware is designed for complete metal to metal connections which means stages can't be cut away if a bolt snap sticks. Really stupid.

8. The argon bottle is steel which has poor buoyancy versus an AL14. It's designed to be hardmounted on the backplate like the canister light. See problems with canister light.

9. Slobwinder. No comment.

I could go on, but these are the highlights. As you can see, these are all design related comments. I won't speak to the fabrication as I've never owned a piece of OMS gear and never will. With bad design, the quality of manufacture is moot anyway.

For the money, there is better gear. Most of the Halcyon and some of the Dive Rite (but not much) is better. Halcyon wings are the best but the Dive Rite Classic is OK once you replace the rapid exhaust with an elbow, shorten the inflator hose and take the stupid little ball off the rear dump. I think SP also makes a decent wing modified as with DR. The Halcyon backplate comes properly rigged, but most backplates, including OMS, can be configured this way. Better manifolds are made under a variety of brand names including Halcyon, Scuba Pro, Dive Rite and Sea Elite. They're the same thing but for the knobs. Halcyon and AUL make better lights. Highland Mills makes the best bands, bar none. Better stage bottle rigging can be made by hand in about five minutes.

In general, you'll find newer tech divers using the OMS stuff. It looks cool and "technical." The more experience someone has doing this type of diving, the more they tend to shed unnecessary gear and go with what really works. "Brand" is irrelevant per se. It isn't a fashion show.

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