Re: [PSUBS-MAILIST] What's happening here.

["Captain Nemo" <vulcania@interpac.net>]

----- Original Message -----
From: "Michael B. Holt" <mholt@richmond.edu>
To: "Pat Regan" <personal_submersibles@psubs.org>
Sent: Monday, September 25, 2000 12:02 AM
Subject: [PSUBS-MAILIST] What's happening here.


> This is off the list.
>
> I have the copies made, but I need to make copies for myself.  I'll
> get your stuff in the mail by Wednesday.

MIKE!      If this is about those pages from Busby's book, STOP!!!  I just
bought a copy of MANNED SUBMERSIBLES via eBay.  Muchly appreciate your
efforts, but I no longer need the Busby stuff.   Thank you anyway, though!
>
> My Visual Basic programs to calculate resistance and horsepower is
> now working.  Problem is that the HP numbers are VERY low.  I'm
> not sure if this is because of too little understanding of the
> formulae, improper programming or -- maybe -- it really doesn't
> take much power to move something underwater.

Sure doesn't.  Partly, I think, because an object at neutral buoyancy is
essentially weightless, and their's not much inertia to overcome.  Surface
(form) drag is the big thing.  My boat is actually pretty pointy and the
fins cut the water well.  Once it gets going, it wants to keep going.  Hard
to stop.
>
> The thing I keep forgetting is that underwater there is no
> wave resistance.  That reduces the HP requirements.

Yep.  The lack of a bow-wave when submerged is one of the reasons submarines
are faster underwater than on the surface (when thrust remains constant).
>
> Chapter 5 in Busby is the one about pressure hulls.  I'll add
> that to the collection.  I have to go to school tomorrow and
> probably Tuesday, so I'll copy it one of those days (for some
> odd reason, my school owns a copy of Busby; I'll use their
> copy).

Again, no longer any need.  My copy of MANNED SUBMERSIBLES should be here
soon.  Glad to hear there's a chapter on pressure hulls.  Does he get into
computing crush depth?  I've based my designs on what I know of proven
designs and past experience with watertight devices I've taken to depth
while SCUBA diving.  Then, I overbuild and remained extra shallow.  I
sometimes think the actual reliability of computed crush depth with
homebuilt submarines is less than reliable, because there might be
non-standard design and construction methods used.  Still, I'd like to be
able to calculate crush depth to at least have some idea of what various
designs might be able to tolerate.
>
> I've been thinking about the replica sub I'd build.  While
> doing Verne's Nautilus is immesely attractive, I think I'd
> prefer to do the Seaview.  All I need is a set of plans, but
> the one source seems to have gone out of business.

Speaking of plans, I sent you the plans for the 50" NAUTILUS last week by
priority mail; should be at your place soon.  Be on the lookout for a long
cardboard tube.  ENJOY!!!

The SEAVIEW is a neat looking sub with great possibilities for forward
visibility through those bow windows.  Dual thrusters, too.  Nice boat.
Might be able to find a copy of the plans.  I'll browse around and let you
know if I find a source.

If you really want to blow minds, build a SEAVIEW complete with a FLYING
SUB!!!    ;-)

VBR,

Pat
>
> Cheers,
>
>
> Mike
>