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Brent, bear
in mind that even if you do put flat decks over the MBT's, a K250 is just too
small to go for much of a walk. I'm skinny, but I have the impression if I stood
on the end of a MBT while surfaced it would stand the boat on end way more than
I'd be happy with. Even opening the hatch alters the trim a little, due to
the hatch weight being over the hinge instead of centered. I'm not saying
the K250 isn't admirably stable when everyone is sitting in the right place, it
is. But if you move around, the boat does too. And I recall you mentioning you
might ditch those low-down lead weights on the skids in favor of some
not-quite-so-low extra batteries in the cabin.
:)
Alec The contents of this e-mail are intended for the named addressee only. It contains information that may be confidential. Unless you are the named addressee or an authorized designee, you may not copy or use it, or disclose it to anyone else. If you received it in error please notify us immediately and then destroy it.
From: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Brent
Hartwig
Frank, Before I knew my sub was built by the Captain, I was
thinking of changing both MBT's. The bow would be more of a wave piecing shape
for better towing and the rear would go out a bit further and have a flat
deck so I could bolt a outboard motor on a small transom and be able to get to
it when the sub was surfaced. The outboard would be encased by a small SS
housing so I could dive with it. Fuel would be in a external fuel bladder.
Sent: Wednesday, December 10, 2008 00:58 To: PSUBSorg Subject: RE: [PSUBS-MAILIST] Lifting K-250 Off Trailer the Hard Way My friend that makes SS tanks for a living would proof my design, and fabricate it. It would be nice if I could run the outboard with the main pressure housing submerged, and then have snorkel tubes for the engine air intake, housing breather intake and exhaust, and the main exhaust. This way I don't have the weight issues of having the weight of most of the assembly above water when surfaced to deal with in moments calcs. In that configuration I would need a unlock able hinge assembly with gas shocks or springs to allow me to lift the motor housing out of the water when at the surface, so I can monkey with the motor. I was thinking of using a internal locking ring design for the front and rear ends of the pressure housing for easy access and less hydrodynamic drag. A simpler locking means might work just as well, if I use large soft O-rings. I'll have to work up a CAD model and show you exactly what I'm thinking. I still want a wave piercing bow for towing, so I'm working up a design for a extra FRP fairing I can easily attach for towing ops, then then remove before diving. The trick is figuring out an easy attachment means. Regards, Szybowski From: ShellyDalg@aol.com Date: Tue, 9 Dec 2008 20:50:01 -0500 Subject: Re: [PSUBS-MAILIST] Lifting K-250 Off Trailer the Hard Way To: personal_submersibles@psubs.org Jim/Brent. I can't see the need to calculate battery usage at full
power. Surface travel is the most likely place for full power usage, while
submerged travel is usually done at much less. I plan on using an outboard motor
for most surface travel, and then bringing the small outboard either inside or
loading it onto a surface boat while diving. Again, using a larger motor at slow
speed is more efficient than using a smaller motor at full speed. The prop
losses are a large part of that equation. Bigger prop turning slower is way
better. Frank D. |