37 duffy, ENGINE

TOB

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im looking into having a 37 duffy built,im curious to see whats out there as far as new deisels,and what size i could fit in that boat? any feed back what be great, i want to go big
 

Tuna Hotline

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Worked on a 37 for 5 years. It was powered with a CAT C-12 705hp and it was a great combination. the boat cruised around 22-23kts getting ~1mpg, better if slowed down to 19-20kts. It also topped out over 30kts. It is the perfect combination for that hull IMO
 

Blitzen

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Worked on a 37 for 5 years. It was powered with a CAT C-12 705hp and it was a great combination. the boat cruised around 22-23kts getting ~1mpg, better if slowed down to 19-20kts. It also topped out over 30kts. It is the perfect combination for that hull IMO

I would agree, around 700hp would be a nice power package, as far as engines, I would look around your local area to see who has the best service available and go with that brand. Local service is key as you can pay north of $100 an hour just for travel time with a tech and truck.
 

Frank Grimes

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Ask around about the FPT Iveco 13L motor, putting out 825hp....I THINK it's comparable in size to the C12 & QSM, but kicks out 100 more hp and from what I remember has a better looking torque curve. Try to see if there's a dealer/service shop that carries FPT near you and ask them about it.

Tuna Hotline, what was the boat's running attitude at 30kts? Was it wet and wooly or was the boat stable as if it was running 22? Some hulls can run stable and easy in nice seas in the high 20kt range but others don't like it so much (or they just can't do it at all, the hydrodynamics of the hull render it an impossibility). Not saying this is the case for the Duffy 37, in fact there was a race boat in Maine that ran in the 40's, but I just wonder if it's real world applicable.
 

jerseysportfisher

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if it were mine, i would stick with american power. that fiat cursor 13 is rated 500hp. And its still a fiat. If i wanted across the pond power i would look more towards the DI16-42 Scania
 

Tuna Hotline

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Ask around about the FPT Iveco 13L motor, putting out 825hp....I THINK it's comparable in size to the C12 & QSM, but kicks out 100 more hp and from what I remember has a better looking torque curve. Try to see if there's a dealer/service shop that carries FPT near you and ask them about it.

Tuna Hotline, what was the boat's running attitude at 30kts? Was it wet and wooly or was the boat stable as if it was running 22? Some hulls can run stable and easy in nice seas in the high 20kt range but others don't like it so much (or they just can't do it at all, the hydrodynamics of the hull render it an impossibility). Not saying this is the case for the Duffy 37, in fact there was a race boat in Maine that ran in the 40's, but I just wonder if it's real world applicable.

Frank, we rarely opened the boat up above 23kts, but IMO it was quite stable for 30kts. It was certainly a different feeling than being on a deep-vee CC @ 30kts, but i would not say that it felt dangerous or out of control. Certainly different than when running at 22, but I would be confident that it was not too fast for the hull by any means. The 37 was designed to be a faster, more efficient version of the 35, so it makes sense that it would be stable at higher speeds. Now, if it was the 35 hull at 30kts i think it would be a different story all together.
 

tunaorlater

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My buddy owns a 37 with a 540 cummins. The boat has an easy cruise of 20 knots loaded to the canyon and 22 in most conditions. Wot is somewhere around 27 knots but I'm not 100% on that. It's a good ridding boat and seems much bigger then my 36nb.
 

Frank Grimes

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Frank, we rarely opened the boat up above 23kts, but IMO it was quite stable for 30kts. It was certainly a different feeling than being on a deep-vee CC @ 30kts, but i would not say that it felt dangerous or out of control. Certainly different than when running at 22, but I would be confident that it was not too fast for the hull by any means. The 37 was designed to be a faster, more efficient version of the 35, so it makes sense that it would be stable at higher speeds. Now, if it was the 35 hull at 30kts i think it would be a different story all together.

Thanks, that's great feedback

My buddy owns a 37 with a 540 cummins. The boat has an easy cruise of 20 knots loaded to the canyon and 22 in most conditions. Wot is somewhere around 27 knots but I'm not 100% on that. It's a good ridding boat and seems much bigger then my 36nb.

I remember on Noreast somebody had posted a pic of an unfinished 37' Duffy kit next to a similar 36' NB kit (it might have been Blitzen when he was building his boat) and it looked like the Duffy could swallow the NB whole, with room for dessert. I think the angle of the photo had something to do with it, but still you could tell that the 37' was a larger boat than the NB without question.
 
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