Repowering to Diesel - Sailboat

[AtlanticPeter]

As mentioned the Yanmar 1GM10 is a candidate. I received a quote for $6300 CDN from a major dealer in Eastern Canada. Could I do better buying in the US taking taxes and duty into consideration?

[philSweet]

Nobody's mentioned prop (mis)match?

If your prop is too big it will tend to cause these problems and you won't get rated power. No reason that motor shouldn't give satisfactory performance at cruise rpm with a clean bottom. Try the following-

Tie to a dock and go full throttle forward for about a minute at report engine RPM and the spec red line. You ought to be able to get near red line, say 150 rpm less. If you are 600 rpm less you have too much prop for in and out of the marina duty. If you want extremely efficient cruise that is different, but since you couldn't burn 3 gal. a day if you tried, that is getting pretty silly. Prop description and tranny gearing would help at this point also. There is a terrible "bigger is always better" misunderstanding out there, and somebody may have fiddled with the prop. There doesn't happen to be a cute little "spare" 12 X 13 two blader in a laz somewhere, does there? (12 X 13 is a guess, couldn't find stock prop in a quick search)

[FAST FRED]

Tie to a dock and go full throttle forward for about a minute at report engine RPM and the spec red line. You ought to be able to get near red line, say 150 rpm less.

Not if the prop and engine are properly matched to the boat.

A boat is MOVING and that is taken into consideration when spercifying the proper pitch.

Big difference between zero K and 5K or 6K the usual sailboat will cruise at.

BOllard (0K) pull is hardly a requirement for a sail boat .

The fact that the cruisers prop has "too much" pitch is hardly a problem docking where the engine is usually at idle , and speed is controlled by going in and out of gear.

Any proper set up cruiser will see no where near 150 less than full RPM tied to a sea wall.

The proper chosen prop will allow the boat to cruise at a low (QUIET!) rpm.

FF

[michael pierzga]

Don't know how they do it on powerboats but for sailboats you choose the best guess prop pitch diameter then run the engine..when you feel the prop is to small ,you add pitch and watch the exhaust temperature...exhaust temp is the key indicator for choosing the max size prop.

[FAST FRED]

you add pitch and watch the exhaust temperature...exhaust temp is the key indicator for choosing the max size prop.

WE do it differently , with in reason we select the largest reasonable prop diameter that will fit on the boat , match the tranny ratio to the diameter and then select the pitch with the boats cruise speed in mind..

Since diameter is far more a determinant of HP absorbed , and therefore thrust , this usually is great.

The only hassle are the "racers" that will use the smallest diameter ,huge pitch (less drag under sail) spun with a lighter 1-1 tranny and only want 5K in calm water for the race measurement.

FF