In article ,
Y wrote:

Hi all. I am looking for a long-range trawler and notice that many
converted fishing boats and other interesting (for me) ships have just one
engine. Many of the two-engine ships are semi-displacement ships. I
don't like those much. I just want two engines for when I'm in the middle of
the ocean. So there my question. Given that there is plenty of space in the
engine room, are there systems that would allow me to to fit a second engine
and switch between the two engines WITH EASE?

What I would actually like best (and what would be cheapest I suppose) is to
have to half power engines driving the single prop at the same time but I
suppose any system that would allow me to do that would be quite expensive.
I know it can be done though, since e.g. on the Denmark to Iceland ferry I
was told they use 4 engines to drive 2 props and selectively add or take off
engines based on power requirements (or engine failures I suppose)

So.... anyone?

Thanks

A fellow I met with a large (90-foot) "expedition yacht" told
me his arrangement was a single propeller shaft driven from the
main diesel engine, but also incorporating a hydraulic drive unit.
In the event of main engine failure, the two generators could be used
to turn the main shaft via this hydraulic coupling.

Many military vessels use diesel-electric drive, where the actual
shaft is turned by a very large electric motor. This allows
many coupling arrangements by electrical switching of the current
to the main motor, but this is generally too expensive for most
private yachts.