Friday, August 28, 2009

My Offboard Bailout Kit



After much careful thought over the past year, I arrived at two conclusions:

1) A BOV is an important piece of safety equipment
2) Hooking it up only to onboard gas is insufficient for my diving

One of the things that really pushed me to it was a story a friend told me. For whatever reason he took a CO2 hit, and began hyperventilating like a freight train. His head was still clear, so he pulled out his bailout reg, held it in front of him, and...was stuck. Even though the reg was inches away, he couldn't stop panting long enough to swap them. Eventually he was forced to, and wound up inhaling water.

The first order of business was selecting a BOV. I dived a Sport Kiss for years, but wasn't impressed by the Paragon BOV. I never really had a need/opportunity to bail onto it under duress and at depth, but simply based on the design of the rig, plus the fact that I was using sodasorb, it always seemed to be gummed up, difficult to close, and in general not a high-quality piece of kit. I replaced it with a Mares BOV on my Classic Kiss, but there too it I didn’t feel totally confident, and anyways I never cared for how it projects out in front. I liked the idea of the JJ BOV from the standpoint that it is tidy, compact, and runs off a scubapro reg, and have since picked one up and put it on my Mk15. Shortly thereafter I saw a used Golem Gear BOV at a reasonable price, and am currently running it on my Meg. I much prefer the big knob on the front to the barrel twist method, and despite my misgivings about having such a large reg on the GG I’ve scarcely noticed it. Just to make things sillier I also picked up an RB80 BOV, but haven’t had a chance to dive it yet; I’ll try to amend this when I do.

But I digress, this is about the bailout kit, not the bailout valve. While I can appreciate the arguments for using a manifold, and have even machined some for other peoples’ Megs, I’m not 100% comfortable at this point with using one. Thus, for simplicity, my goal was to just run a hose to a quick disconnect on my bailout tank and be done with it. Since I knew I would be tweaking it I elected to use AP hoses, since those can easily be trimmed to the desired length. I did not, however, go with their QDs, since their 40m depth rating is insufficient. That left the Omniswivel QDs, as well as the Swagelok ones. I wasn’t crazy about the having the pin exposed on the Swagelok system, as it seemed rather small and like it might be vulnerable. I called Omniswivel to discuss depth limitations, and was told that they are still in the process of testing them, but that the 100m test showed no perceptible (per the machine) change in WOB at 100m. Good enough for me, so that is what I used. If you look at the end of this I've attached a Bill of Materials. What I have not done, and may yet, is install a check valve in the line. I currently have the female QD on the bailout tank, simply because this has its own internal check valve. What that means, however, is if I disconnect the line under water, some amount of water could go up the male QD. What I need to do is test this underwater, and see if it significant amount, or so neglible that it gets blown out when I purge the reg. The BOV hose is loosely held to the corrugated hose by some velcro straps, and then runs down the inside of the Meg counterlung. Very clean, very neat. I hope to transfer this system intact to my Hammerheaded Mk15, running the hose through where the old on-off switch was, as well as to my Sidemount Rebreather and Classic Kiss.

All of my bailout has been sidemount for several years now, which was an immediate smack-myself-in-the-forehead, why-didn’t-I-do-this-sooner experience. My big concern however was that I could no longer see my bailout reg in an emergency. In order to lessen the impact I almost compulsively put my hand on the bailout 2nd stage multiple times during the dive, to build muscle memory and to reassure myself that I can have it in hand immediately if need be. I was surprised, shocked really, at how much more relaxed I felt with the BOV, knowing that all I need to do is twist the valve and I’m on a full 80. It’s kind of like a weight I didn’t know was there has been lifted. This is not, however, an unalloyed virtue, since I don’t want to lose the muscle memory, and will need to make an extra effort to keep that skill sharp. Besides the fact that there might be a problem with the BOV (qv the deeply disturbing issue with the JJ), there is also the idea that the BOV could be pulled from my mouth, either by wreckage, the ladder, or a panicked diver. In addition to sorting the BOV and offboard kit I recently spent some time fine-tuning my tanks. Diverite has some very high quality, inexpensive cam bands, so gone are the hodge-podge of straps, hose clamps, lines, and sundry bits, including the occasional metal-to-metal connection. With the help of some 1# weights on the cam bands the tanks are also properly weighted, even with helium, and sit right where they oughta. To prevent fumbling I use a sideport reg (as I believe all secondary regs should be) on a 7’ hose (ditto), 2 more little things that give me the warm fuzzies.

So that is my thought process and the end result, hope it can be of use to somebody.

Bill of Material:
From AP:
AP300/48 1 pc Regulator hose, 48” 65.84 each
AP300/15 2 pcs ADV Supply Hose (short) 54.45 each

From Golem Gear:
OMNI_QDM-YM 1 pc QD Male to 9/16-18 Male 10.00 each
OMNI_QDF-YM 1 pc QD Female to 9/16-18 Male 64.00 each
OMNI_SZF-ZF 1 pc 3/8-24 Female to 3/8-24 Female 15.00 each