A VW diesel in a sailboat would probably last forever, running
2500rpm, but by the time you 'marinized' it, it would probably be
more expensive (with more weight/hp) than a new marine engine.

Take a look at:
http://www.volkswagen-marine.de/
for the already-marinized VW's
and
http://www.ejbowman.co.uk/products/index.htm
for a supplier of marinizing parts (Exhaust manifolds etc) for VW diesels
and
http://www.lancingmarine.com/dieseliz.html
for a number of diesel conversions, and
http://www.lancingmarine.com/sdieselb.html
(See right columns for two types of VW diesel marine conversion parts).

There are a LOT of boats in Europe, the Eastern Atlantic, and the
Mediterranean, and many of them have smaller diesels.

The US seems to think a Bayliner with raw water cooling is a great
idea...

--
Regards, Terry King ...In The Woods In Vermont

The one who Dies With The Most Parts LOSES!! What do you need?