Re: boat propulsion - miniature computer-controlled steam plant?

"Jim Wilkins" <muratlanne@gmail.com> writes:

"Leon Fisk"  wrote in message news:utkim4$32jtl$1@dont-email.me...
>
LUDINGTON, MI – The S.S. Badger car ferry marked the 71st anniversary
of its maiden voyage across Lake Michigan on Thursday, March 21,
officials said...
>
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That's quite a service record. Ocean liners on the North Atlantic run
wore out in 20-30 years.

25 years service life before scrapping for ocean-going ships: about
equally dependent on at least these two dominating things

* seawater corrosion
Seawater happens to be for steel the "pessimum" composition - if you add
more salt it becomes less corrosive (?).  Corrosion is ferocious.

* fatigue
The ship going over ocean waves goes alternatively between "convex" and
"concave" bending - wave peak in middle of ship; ship on waves at bow
and stern.

Both of these are attacking all over the ship, likely in places you
cannot easily see.
Then yes machinery is coming up to needing refurb. - which could be done
- but isn't worth it when faced with the big two of corrosion + fatigue.

There are freighters on the Great Lakes at around 100 years old.
Being on fresh water (vastly less corrosive) and without the coean waves
(no fatigue) this can be so.

Also - apparently - the steam-turbine ships as very quiet and smooth -
if as family of someone to do with the Company you get invited to be
passengers on a voyage you go on a steam-turbine ship.

The bulkers used to be coming in and out of Cleveland when I was working
there.
Manouvring out in the Cuyahoga river, there was some heat-haze above the
funnel (stack).  Was hilarious sight on Friday nights when everyone
partying by the riverside and pleasure boats around on the river while
another 20,000 tonnes of cargo went on the move.