Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!att!cbnews!cbnews!military
From: robinro@bomber.ism.isc.com (Robin Roberts)
Newsgroups: sci.military
Subject: Re: Electric warship propulsion
Message-ID: <1990Dec28.032354.3718@cbnews.att.com>
Date: 28 Dec 90 03:23:54 GMT
References: <1990Dec22.033410.22947@cbnews.att.com>
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From: robinro@bomber.ism.isc.com (Robin Roberts)

In article <1990Dec22.033410.22947@cbnews.att.com>  writes:
>
>From: sun!portal!cup.portal.com!Eric_S_Klien
>The nuke subs have no electric batteries and we have no diesel subs.
>Note that this means that our nuke subs run louder than diesel subs
>that are running off their batteries.
>                                                          Eric Klien

Unfortunately none of this is exactly true.  Nuclear subs do have batteries
they even have diesel engines in case of a breakdown in the nuc plant. The
U.S. even has diesel subs, just a handful of the Barbel class.

Nuclear submarines have a higher minimum noise than diesel submarines 
because the nuclear plant has to circulate some water even at the lowest
power levels to moderate the temperature of the core.  The circulating 
water increases the minimum noise level.  Diesel submarines can operate
at very low noise levels on battery powered electric motors or no motor
at all.

Some experiments have been made with what are termed "natural circulation"
power plants that can operate without any pumps going at low power levels
some of this technology has been incorporated into the later U.S. nuke boats.

The disadvantage of a diesel is that when it is charging its batteries it
is as noisy if not noisier than any surface ship.  It is slower to deploy
to an operating area and has limited range.  Its range is even more limited
if for tactical reasons it cannot operate its diesels to charge.

-- 
Robin D. Roberts           | <This space closed for remodeling.  Watch for
Interactive Systems Corp.  |  a new witty quotation scheduled to open in
Calabasas, Calif.          |  the Spring of 1991! >
Internet: robinro@ism.isc.com CompuServe: 72330,1244 GEnie: R.ROBERTS10