Re: [PSUBS-MAILIST] Wetsub carrier water transport systems

[VBra676539@aol.com]

Launch and Retrieval Platform--they were (are?) towed aluminum catamaran rafts with grating decks and big ballast systems. Two divers piloted it, with the sub on deck. Take the LRP down to 60 feet or so, release the sub, surface. To go home, repeat in reverse. Sort of like what you have in mind, only they did the sub transfer underwater, where there was no wave action. Mucho important when you are trying to mate 5 tons of submarine to 5 tons of raft. Banging be a bad thing, I can assure you.

Green gas beeze chlorine, yes. Pretty tough on the fire fighters, who were hoping like hell that the hydrogen we couldn't see was going to be nice and vent out of there without spitting Trojan batteries as projectiles. I've seen a pod go like that (in the shop at Perry) and brother, let me tell you, it ain't a pretty sight.

Leak detectors are very simple in theory. It's just a little DC open-circuit deal that closes when shorted by water in the bilges or wherever and lights the light. Take a little block of PVC, attach two stiff wires a quarter inch or so apart, then glue or screw it on the inside pod bottom so the wires just clear the surface (1/8" to 1/4"). Then run a pair of wires from it, through the pressure vessel wall, and out to your cockpit. Make a little cannister of PVC or acrylic or something, as this is a wet sub, so things will stay dry. Inside, power it through switches with a couple of 9-volt batteries to LEDs or something, and a buzzer. Don't use the sub's main power system, as you want to know about a leak whether you are powered up or not. Keep it totally isolated and independant. Goop everything down so errant splashes and condensation won't cause any problems, and you're in business. Total cost, with batteries, $17.36 or thereabouts. (Okay, I'm guessing. It might go 20 bucks).

Speaking of which, how are you protecting the penetrations and electrical system? If you do have a leak, and a major short, straight cables will toast a hole in whatever is handy and blow you out of the water. A simple solution is to build in-line fuses. Size them to maximum draw for the system and cable, then cast them into PVC tubes using 3M goop or something non-flammable. A major short, such as you might expect with seawater intrustion, will pop the fuses and reduce your problem to the pod itself. We may all bow our heads now and pray that it never happens, but should it come about, at least you'd know what to run FROM!

As for vents, I'd use SS fittings, maybe a 1/4" going in, and a 3/8" or 1/2" going out. Put bulkhead shutoffs near or directly into the pod, and valves up high. Hook a regulator to a gas supply, attach it to the goes-in valve, start a slow flow (just a little air action will do it) and you have your vent system. If you plumb it high on the boat, then you could charge in the water, no problem. Also, have the input line and output lines on opposite ends of the pod. You could do it with both fittings in one penetration, just run tubing from the input line (inside the pod) to the front.

Compensation is another deal. If you were talking about oil, I could probably help, but I've never used air to do it. It seems to me that the equalization process is more trouble than it is worth for the pod, which ought to be strong enough to dive where you expect to dive. Psubs has some really creative guys who have experience with this, so I'm betting someone will help you out.

If air compensation causes you problems, then you might want to consider modifying the motor housing to improve its capabilities. That will take some machine work. You'd want to cut a proper O-ring groove in the sections, and root out enough metal around the prop shaft to allow a pump seal of appropriate size to be installed. It isn't all that complicated a process, and Dan H. has a whole machine shop up there in Pennsylvania with about four feet of snow in the parking lot. Send it to him. He hasn't got anything else to do, anyway-----Right, Dan?

I'm looking forward to seeing this critter. Couldn't find you on the moki pages, so maybe they haven't posted it yet. I'll keep an eye out. At present, I've got half a dozen Spanish speaking roofers banging away at my new shingles, so that's keeping me busy.

Best Regards,
Vance