The QSB is about 600 pounds heavier than the Yanmar. Isn't 1500lbs a little too heave for that hull?
Yanmar 6BY3-260 hp...or the 315 hp both are nice motors...I have two friends with the H&H 27 and 29's.....they are commercially used and have cummins motors
I am in the process of repowering my 29 now. I am installing a yanmar 315 hp with a 2.5 to 1 gear and a 4B 22x22 prop, Looking at A prop calculator I am hoping for a 17 to 19 knot cruise @10 to 12 gallons an hour 20+ WOT
I do not know much about the new BY motors. The 315 Yanmar would be ideal however it is not longer being made. If she was my build I would go with a 6LY3-UTP @ 380 HP Yanmar. A great power planet. Weight is640 lbs. less the gear. I would also use a 2:0 ZF85A transmission with a total weight of 730 lbs.
If this is too much power for you my next choice is the 330 HP Cummins.
Good luck with your new build.
Well only my opinion with my #s. The BY is a real sewing machine, She come it at 4000 RPMs. They are velvet smooth & quiet. Do not let 4000 RPMs scare you. These new diesel are different animals that years ago.
260 BY would need:
with a 21 X 20 or 20 X 20 Dyna Quad
WOT throttle performance @ 4000 RPMs would be 21 Knots
Max Cruising RPM of 3600 would be 19 knots.
1.5 shafting is plenty.
Thanks for the response.
What about a 4LHA-STP 240HP at 902lbs with gear? What gear, prop, and speeds?
You are right, I am a little concerned with a 4000RPM diesel. The 4LHA-STP is a 3300RPM engine and also more displacement than the BY.