Re: [PSUBS-MAILIST] Buoyancy

One thing that worries me is that there has been no real discussion of jettisonable equipment (thruster, manips, etc.). Self rescue is the most dependable kind, for sure, so while you're looking at all the props and whatnot on your saucer, give some thought to how really nice it would be just to leave it down there along with the fishing line or net tangled around its prop. You can always get a new thruster.

As a for instance to what happens when you don't do that (and Perry didn't build ANYTHING jettisonable) I was down in the Auk Field in the North Sea with Joe Shannahan and Les Lynch one day aboard PC-9, riding the back seat. Les was in pilot training (I was the junior man then). Somebody managed to suck a 1/4" poly marker buoy line into the forward vertical thruster, then backed around trying to clear it and wound ANOTHER line of similar ilk into the main wheel. We were then safely moored to a 98,000 pound pattern anchor at just shy of 300 feet, which is only handy if the currents are giving you a really bad time, which they weren't, as it happens.

Side note: You ought to see the pictures. That anchor was the size of a pick up truck. A really HEAVY pick-up truck. The oil transfer buoy at Auk, essetially a loading station for super tankers, had 16 of those puppies in its spread, with chains over a quarter mile long that weighed substantally more than the anchors themselves. They meant for that baby to stay put, my friend.

At any rate, it took three hours of fiddling to break/cut the forward line, and the back one took took everything we could shove to the main motor (appx.100 amps @ 120 volts, if you're interested) and three quarters of a ton of positive lift in the main tanks. If it hadn't broken then, we had a half ton drop weight left to release (and an uncontrolled ascent to look forward to). We were about an inch from dropping that thing when the second rope finally heated up enough around the shaft seal penetrator to weaken sufficiently that we could break it (I've still got a piece, melted flat on one side). Now, that's what I call a long afternoon, and if PC-9's MBTs had been any smaller, then Les and Joe and I would probably still be sitting in the Auk Field looking at that damned anchor.

The point being that it took a massive, industrial grade kind of submarine and a healthy dose of luck to break out of there. One of our garage specials wouldn't have a prayer under the same circumstances. We need to be proactive and thinking way, way ahead of the curve on that kind of deal. I don't have droppable thrusters yet, either, but it is definitely on my work list. Better shed than dead, I say.

Hi Vance. Thanks for the note from experience. Advice like yours is damn hard to come by, and I appreciate it.

Quote..."I don't expect to need to blow the tanks dry while submerged at any great depth, but I want enough capacity so that I CAN if I need to."

That sounds like a pretty scary scenario, being hooked on something, or for any reason really, not being able to get back up.

I think that's why this whole "rescue" subject keeps popping up.

Frankly, I don't hold out much hope of a rescue if I go down and get stuck. I plan on having a support boat, a crew with scuba certs and a radio, but let's face it, how the hell is the local Coast Guard going to get us out of there. Don't seem too likely to me.

For those of us that have NO experience, trying to imagine what MIGHT happen, and then making contingency plans, is sometimes frustrating. There's a point at which we just have to hang our ass out in the breeze and try our luck, but the things that we can control and/or anticipate need to be addressed in the design/build stage and I know for sure I haven't thought of every thing. Keep an eye on us "newbies" and feel free to kick us in the ass if we get off on a stupid idea. Thanks again, Frank D.