What engine What size

[norseman]

HI Board
I've recently purchased a little Winga 78 motor sailer, she sails quite well but I think possibly the old MD11c/110 sail drive unit will need replacing sooner than later,( white smoke/ steam ? ) although she starts and runs well enough.
The options i'm considering are Volvo 2020 and Yanmar 3gm30F. She weighs 3.1 tons, and the Volvo at 19 HP should do, but should I go for the 27HP Yanmar. It is quite a big purchase, and I would appreciate any advice.

 

[JamesS]

When I made a similar purchase a few years ago I was told to work on the basis of 4HP of engine per ton of boat - it seemed quite successful.

Cheers

 

[Plum]

I agree with JamesS that 4hp per tonne diplacement is a good target.

 

[Celena]

Correct for a yacht, but as the boat's described as a motorsailer I'd go for 50% more...

 

[ccscott49]

So the 19hp he's thinking about should be just about right, I wouldn't go for the 27hp, yanmar, just too much.

 

[richardandtracy]

When I built my Bruce Roberts Spray 36, the plans stated an engine size 23-33 hp. Then, when I suggested to BR Designs using a 2CV engine (29 hp) they asked (not in so many words) "What kind of idiot suggested you use one that small?". I didn't get any response to "Well, you did actually".

The Spray 36 Steel is approx 11 tons, and the pilot house version has fairly high windage.

So what engine did I put in? None. Spent the money on making lots of anchors (5 total, 3 at the bow and 2 at the stern) and heaps of chain.

Regards

Richard.