From: dpe@inel.gov (Don Palmrose)
Subject: Re: Sweden Attacks Sub?
Organization: INEL EG&G Idaho
Date: Thu, 1 Oct 1992 12:28:58 GMT


From dpe@inel.gov (Don Palmrose)

In article <BvE5rp.2sy@lawday.DaytonOH.NCR.COM>, tomas_e@LINK.Physchem.KTH.SE (Tomas Eriksson) writes:
> 
> Let's assume that these submarine activities against Sweden, Norway and a 
> few other places were given high priority and a lot of resources. Remember
> that crew saftey had *low* priority, and remember that the Soviet Union 
> produced satellites with nuclear reactors. If the intruding subs are 
> indeed 30 m long (I think I've heard slightly smaller numbers - a 
> Swedish 1,000 ton submarine is about 50 m long), this is probably
> sufficient to install a small nuclear reactor.
> 
> A nuclear reactor would give these subs an endurance far beyond what one 
> would expect of a submarine this size. Indeed, there are indications 
> that the intruders have gone into hiding for a several days when the ASW 
> activities have been intensive. Usually, Swedish submarines are on 
> patrol much longer than surface vessels after a ASW action has been 
> called off. If nothing else, they can listen to the intruders when they 
> leave.
>  
> Tomas
> -------------------------------------------------------------------------------
> Tomas Eriksson                                          tomas_e@physchem.kth.se
>             Surface Force Group, Department of Physical Chemistry,
>                Royal Institute of Technology, Stockholm, Sweden
> 

Diesel/Electric subs are much much quieter than a nuclear sub and this is why
they are the perfered sub for shallow water operations.  True, they cannot 
sit on the bottom for days on end, but one generally does not want to be in
shallow restricted waters for long periods of time (i.e. more than a couple
of days).  This is because the longer you stay the greater the chance of being
found by accident (fishermen have been known to hook a sub in coastal waters)
or by the enemy ASW forces (sea bed hydrophones, another sub, or, by some
stroke of luck, a surface ship).  Also, the sea currents due to the tides can
cause big problems while on the bottom if one is not careful.

A small nuclear powered sub would overcome the endurance problem, but the
small size would also limit speed.  Plus the faster the nuclear sub goes, the
noise problem gets only worst.  Thus, if the sub needs to get away fast, it
probably can't due to engine size, noise, or restricted maneuvering space. 
Thus a nuclear sub would face moving just as fast as the Diesel/Electric (DE)
running on batteries.  So is the endurance advantage large enough to overcome 
all of the noise/speed problems?  Maybe, maybe not.

FYI, the US Navy has (had?) a small nuclear sub known as NR-1 and I would 
recommend Jane's as a good reference for info on this sub.  But from what I 
have read on her in open literature, she is extremely limited due to food,  
crew comfort, and speed such she can only operate for several days away from 
a tender (or mother) ship.

Thus IMO the stealth of the DE sub on electric drive far out weighs the 
advantage of endurance for the nuclear powered sub in shallow water ops.

Don Palmrose
"I'd rather not serve on a ship designed to sink...."




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