What would be good design criteria for a set of skids?
It seems that you want a large surface area, but would you want wide and flat skids(allowing mud to cover over the top) or would you want wide and tall skids(allowing the mud to achieve suction on the sides of the skids)?
It would be easy enough to attach the ends of the skids to the hull to stop them from entangling things or wedging into crevices. By attaching sheet metal(or something of the sort) in between the the skid supports and the hull, you remove a loop which might also become entangled. Any thoughts on how high above the bottom the skids should support the hull?
Having the drop-weight system fixed higher in the sub would add muck safety, but may cause freeboard and stability problems on the surface. I like the idea of blowing air through holes in the skids to relieve the muck-suction, but you would go through your compressed air real quick. Pumping water through the same system would be just as effective and would only require that one add electrical though-hulls to an existing pressure hull, keeping a submersible water pump at ambient pressure outside the hull.
Perhaps this isn't the topic under which to discuss skid design, but this a part of PSub design which I have failed to consider in-depth.
Shin
"And further more, be advised that although this is actually a live broadcast and is being sent out at this very moment, it is quite possible that it may arrive tomorrow, right now, or perhaps even yesterday." -Serial Experiments Lain ep#8
----Original Message Follows----
From: VBra676539@aol.com
Reply-To: personal_submersibles@psubs.org
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] little sub brother again
Date: Tue, 16 Jul 2002 17:15:59 EDT
In a message dated 7/16/2002 11:00:17 AM Eastern Daylight Time,
drmason2001@yahoo.com writes:
<< A sub that you plan to bottom out will
need design features built in to make sure you can go
away again when you are done with your task. Things
like water jets in the skids, extra upward thrusters,
ballast drop that wont hold on after release,
break-away skids as a last resort, and even maybe an
escape pod of some kind. Build it to set down on good
bottoms, but with the means to get loose from bad
ones, or don't put it on the bottom at all.
Just my thoughts here.
>>
Sorry boys, but this is a waste of mental efforts. If the sub has a
reasonable skid system, then you've got to have a SERIOUS screw up in
progress to do more than pick up a few pounds of the gray stuff. Deepstar
4000 scooped enough into her fairings to require dropping the big weight
once, for instance--And there is the old, old story of the Trieste dragging
its trim chain enough to bind it up. I don't suspect this will be a psub sort
of problem (and most likely not at 20,000 feet, either). Just don't put any
handy load areas on the bottom of the sub, and keep yourself trimmed
reasonably light, and this will not be a problem.
Even trimmed heavy, a Pisces or Perry boat wouldn't weigh much over a hundred
or two hundred pounds, distributed over 4 to 6 inch wide skids 10 feet long,
they sat light as a feather, and left tracks in the ooze about two inches
deep. You can sure pick a few dozen pounds of mud up if you fool around for a
while on the bottom, but the ballast systems can lift it.
Vance