RE: [PSUBS-MAILIST] Dive to Turn?

[Chris Nugent <dirkpitt77@yahoo.com>]

   FWIW, I read somewhere that the first military submarine with a hull streamlined for full-time underwater operation,  the U.S.S. Albacore, had, at least in one phase of its existence, a rudder type setup on the trailing edge of the sail, the very purpose of which was to counteract the severe rolling action they encountered during high speed turns.  If I remember right, the relative short length of this boat was a factor in its tendency to roll, so later designs tended to be longer, and the sail-borne rudder was discarded.  I don't remember where I read it.

 

                                                                                   Chris

Alec Smyth <Alec.Smyth@compuware.com> wrote:

Ian,

I have zero military sub experience, but have read that they can roll
undesirably when turning at high speeds. The reason is that the sail,
when not meeting the oncoming water exactly head on, acts as a giant
airfoil. At PSUB speeds, I can't imagine this being a factor. Plus, most
PSUBS don't have a military-style faired sail.

Solo will indeed bank into turns, just like a plane.

Thanks,

Alec

-----Original Message-----
From: Ian Roxborough [mailto:irox@ix.netcom.com]
Sent: Wednesday, May 04, 2005 8:32 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Dive to Turn?


I think this might depend a lot on the sub in question and
it's balance.

I've heard a few people describe there sub turning on the
surface, but not underwater. The main comment I've heard
people say about there sub was that it listed to the outside
of the curve (like a battleship when it's turning).

If a this "listing like a battleship" was to happen underwater,
giving the rudder a slight off vertical angle, then I think
the force it might cause the sub to assend rather than dive.

If the sub was to list more like a motorcycle (in to the curve
rather than away from it), then the slight off vertical rudder
angle might cause it to dive.

In both cases, I think the effect would not be very noticable.
It might be noticable in hydrobatic submarines like Solo.

Cheers,
Ian.

On Wed, 4 May 2005 17:07:39 -0500
"Cliff McDonald" wrote:

> Question: When a sub is turned sharply at speed, using only the
rudder, will
> it dive as well? It seems to me that some roll would be induced by
> centrifugal forces on the heavy part of the sub (lower part) which
would
> cause the rudder to be in a non-vertical position and point the sub in
a
> turning and diving attitude. Would this be a problem at speeds of 4-6
knots
> and if so, is it correctable? Thanks, as always,
> Cliff
>



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