Re: [PSUBS-MAILIST] How much HP?

["David Paget" <david@ryma.com.au>]

You could check your hull and discplacement figures using the propking  /
propcalc spredsheet in the design section of P-Subs web site.

----- Original Message ----- 
From: <DJACKSON99@aol.com>
To: <personal_submersibles@psubs.org>
Sent: Sunday, June 15, 2003 12:37 PM
Subject: [PSUBS-MAILIST] How much HP?


> I know this is really a boat question and I posted to a boatdesign.net
too, but I am sure someone here may be able to help as well. I am designing
an ambient submarine that I will power with a jet dive when surfaced. The
specifics are below. What I need to know is how much horse power will be
needed in order to get the boat to plane and at what speed the boat will
plane? I am not so interested in going 30 mph but I do want to be sure that
the engine selected can obtain planing speed.  I have seen a chart in
"Boatbuilding with Aluminum" (pg 15) that indicates a 120hp would push 4500
just over 30 knots. Is that realistic for something like a Mercury 120hp Jet
Drive?  Where can I find additional formulas for calculating planing and
maximum speed?
>
> Length 20 feet
> Water Line Length: 17 feet
> Beam: 50 inches
> Hull: 12 degree V-Hull
> Draft: Aprox 16 inches
> Displacement: Aprox 4400 to 4900 (depending on engine weight)
> Design Images:
http://members.cox.net/djackson001/sub/Sub_H7_files/Sub_H7.htm
>
> I certainly appreciate any help!
> Doug Jackson
>