On Mon, 27 Aug 2007 06:05:39 -0400, "Armond Perretta"
wrote:

As a practical matter, sailing along and running the machinery in neutral to
power the batteries is probably not the best choice for a number of reasons.
First, you can get a little "kick" by putting the engine in gear. The noise
will be bothersome in any case.

Second, it is generally not a good idea to run small or medium-sized diesels
without a load, so your engine will benefit from doing a little work while
you charge up.

That is all true but sailboats on distance races do it all the time
because they need to keep the batteries charged but can not put the
engine in gear.