Re: [PSUBS-MAILIST] Re: KEN MARTINDALE (was Big Motor..)

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

----- Original Message -----
From: "Michael B. Holt" <mholt@richmond.edu>
To: <personal_submersibles@psubs.org>
Sent: Sunday, September 17, 2000 1:47 PM
Subject: [PSUBS-MAILIST] Re: KEN MARTINDALE (was Big Motor..)


" That's my understanding of the "fair use" idea.  I felt no qualms about
using the formula, with proper credit, in my work.  (All I did, from my
perspective, is translate Busby.)"

Yep!  I think we're all in agreement here.

"I looked back in my annotated "20,000 Leagues Under the Sea," to get the
numbers Verne used.  In Prof. Aronnax's first private interview,
Captain Nemo privides all the number in metric.  That Nautilius displaced
1500 tons, was 228 feet long and cruised at 15 knots.  Quite a respectable
psub."

Sounds like the one Carsten's building now!  ;-)

"I'm working through a table-load of books about ship design, trying to use
the classic formulae to determine horsepower.  So far I've tried four
appraoches, on a spreadsheet, and the accuracy is not good.  I have two more
formulae to test.  More, as it happens."

Great!  Please keep us posted of your results.


" What I see in my exploration is that most smaller boats would not  benefit
from too much mathmatics.  Five horsepower is quite enough."

Generally, I agree.  Unless the objective is a high performance minisub,
most small boats all seem to share similarly slow speeds and limited ranges
of operation when using most common propulsion systems; so, for my purposes,
knowing precisely whether it was going to go 3 or 4 mph at full power wasn't
an immediate concern.  But then again, the abiity to accurately calculate
performance would be really important when designing a bigger sub with
greater intended range capabilities; so yeah, I'd like to know how that's
done.

" I have three-views and sections of Disney's Nautilus.  It must be seen as
a work of engineering art.  Working up the numbers on that shape would be
daunting."

Yep!  That's how it looked to me, too.

"Some day I'm going to print out the plans onto parchment, 11x17, and frame
it on the wall to my library. "

Well, it just so happens I've got one copy of the plans (with a 50-inch
image) in my shop.  Since you've been so helpful to me, send me your snail
mail address and I'll ship it to you.

(I'm setting up, in a 1890 townhouse, a Vicotrian gentleman's residence. To
finish it properly, I'll need also a reproduction of the skull of Piltown
Man.)

Plenty of skulls available at Walmart these days: Hallowe'en, you know.  I
was thinking about getting one for the garden alongside my driveway (to
discourage solicitors).    ;-)

> > (I mean, it's probably a matter of comparing motive
> > power output, propellor efficiency, and resultant useable thrust; versus
the
> > size, shape, mass, displacement / buoyancy, and drag coefficients of the
> > hull; and the unusually ostentatious exterior features of my hull would
> > probably make that process extremely difficult to determine with any
real
> > accuracy.)
>
"That's exactly it.  I've just not been able to work out how to relate the
elements.  I'm hampered by training that conentrates on accounting and
computers, education that centers on the mind of man and old textbooks which
were not written a reference books.  Mike Holt"


Begins to look like a wind tunnel or the like might be necessary to really
know for sure; but calculations should be able to provide a fair
guesstimation of performance, even in the case of an unusually shaped hull,
no?  Anyway,   good luck with your efforts, and please keep us posted of
your results.

VBR,

Pat