Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!att!cbnews!military
From: maniac%garnet.Berkeley.EDU@ucbvax.Berkeley.EDU (George W. Herbert)
Newsgroups: sci.military
Subject: Re: Multiple Screws
Summary: eensy correction...
Message-ID: <6744@cbnews.ATT.COM>
Date: 20 May 89 03:17:19 GMT
Sender: military@cbnews.ATT.COM
Organization: University of California, Berkeley
Lines: 24
Approved: military@att.att.com



From: maniac%garnet.Berkeley.EDU@ucbvax.Berkeley.EDU (George W. Herbert)

In article <6501@cbnews.ATT.COM> jrll@Portia.stanford.edu (john ralls) writes:
>Each shaft/propellor combination has an engine attached to it which is
>able to provide a certain amount of horsepower.  The naval architect
>designs the engine, gear, shaft, and prop[ellor to work together to
>use that power in a way consistent with the mission of the ship.  It

Small detail: we generally PICK an engine& gear, and have someone else
build a shaft and propellor to our specifications.  Very few naval
architects are also into engine design.  Too many moving parts;)
	We do try hard to pick a set that matches the requirements for the     
vessel.  But getting things to work together is more role and mission 
related.  Mission gives power and propellor type, which leads to a number
of useable plants and gear sets...optomize that, run an adequately
sized shaft back, stick on mission optomized screw, und viola! ship moves.

>There is seldom a single reason for any particular characteristic of a
>ship.  Naval Architecture involves far too many compromises.

Very true, not just of naval architecture.  Every structure usually has several
reasons and effects, and often has been optimized for non obvious reasons.