Posted by Gerry on November 13, 2000 at 20:34:45:
In Reply to: Re: DIR question (long) posted by MHK on November 13, 2000 at 18:22:20:
OK Guys, one at a time, first
Mike,
I think we’re getting closer.
If JJ is requesting that his reps tone down the rhetoric, then good for him. He must be doing it via private e-mail rather than public posts.
I conceded the 5’ hose, you just didn’t notice.
We still don’t see eye to eye on ditchable weight. We had this part of the discussion a few months ago. Let me try to restate your position to make sure I understand it. You want non-ditchable weight to guard against a fast ascent in an emergency. You see a fast ascent as a major embolism risk. But to embolize, you must a) ascend and b) hold your breath. Breathing normally, a fast ascent will SLIGHTLY increase your risk of a bends hit (assuming you’re within NDL.) Admittedly this is a bad idea, but it is not life threatening until you hold your breath. You are unlikely to hold your breath if you aren’t OOA. If you ARE OOA, going slow is NOT in your best interest. Remember my point about the sub escape tower down in San Diego? Every submariner the Navy trains does a skyrocket ascent from 110 ft. These aren't divers. Call Pete at AOP if you don’t believe me. They don’t embolize because they exhale all the way up. The way I see it, you’re endangering yourself with this non-ditchable weight in order to protect against a minor threat of a bends hit. Works in a cave, but it doesn't make sense in OW. There is no reason for a recreational diver to wear non-ditchable weight. It presents an unacceptable risk.
Actually, the same drysuit failed three times because of a lobster, a mantis shrimp and a dumb user. Each time it lost some or all of its buoyancy and I was able to get back without a problem using the BC. My point was that drysuit (in my experience) failed more often than BC bladders. If you were diving wet, the loss of a BC bladder wouldn’t even require dropping weights within the recreational envelope. I hate to ramble about the “old days” but we were diving to 130’+ before BC’s were invented. Use the tool for what it was designed for. A drysuit is designed for exposure protection.
As to quick releases, let’s agree to disagree.
Kendall,
3 – agreed
4 – see above
5- I agree that being over weighted is a real problem, but I don’t see unditchable weights as contributing to a solution. See above.
6 – agreed
7 – OK four lb. when full. But having watched new divers flounder to master buoyancy skills (Arguably the most difficult skill an OW student needs to learn). Are you gonna saddle that newbie in trouble deep with four extra pounds easily offset by dropping weight, or will you make him pay for a drysuit plus training, and watch him flounder for at least another 20 dives till he gets it under control?
8 – You make some good points. I’ll cogitate on it a bit.
Terry,
Actually, I forgot about that newfangled SP steel HP 72. I consider that thing a bottle-with-a-built-in-keel-weight. I was talking about the old standard 2250 tank. See #7 above.
All of you,
A good exchange, and I learned a lot. Mostly I learned that keeping this thread straight is confusing. My only REAL heartburn is on the ditchable vs. non-ditchable weight thing, and I’m really interested in gumming that one to death. I care a lot what I teach OW students. I want it to be the best. So, let’s narrow the focus and, if you’re willing, take the discussion back to the top of the list. Maybe we can get some other instructors interested, and Kendall, you’ve read my last polemic, I promise. Somebody take it to the top as “ditchable vs. non-ditchable weight in OW diving.” I’m going out for a pizza.
Gerry