Repower hat53 motoryacht with small engines

[GJH]

Huh? Is the WOT on the 12v71 lower than on the 8v92? How exactly is it not working harder? Again the question is, if it is all about horsepower, why did Hatteras put the 12v71 on the slightly bigger boats rated at the same horsepower as the 8v92? There had to be a specific reason. I am not being a wise guy here, I really do want to understand.

[Boatsb]

Could it be that the 92 series was not released until the 70's and may not have been considered "ready for marine" use in the beginning.

[Vincentc]

Huh? Is the WOT on the 12v71 lower than on the 8v92? How exactly is it not working harder? Again the question is, if it is all about horsepower, why did Hatteras put the 12v71 on the slightly bigger boats rated at the same horsepower as the 8v92? There had to be a specific reason. I am not being a wise guy here, I really do want to understand.

Torque x Rpm / 5252 = Hp

Boats have a single speed reduction gear.

Planing boats require a lot of power to get over the hump and on plane.

A larger displacement engine will usually develop more torque and Hp at lower rpm.

It seems to me that a good way to look at this is Hp at Rpm.

You need a certain hp to push a boat a certain speed. Can your engine deliver that hp at an available rpm?

Engineering from an English major.

Regards

[tom5518]

Could it be that the 92 series was not released until the 70's and may not have been considered "ready for marine" use in the beginning.

Especially since the 8V92 wasn't available in 650 trim until the 80's. I think the 58 MY series 1 was the first to offer the 92's during the 1977 model run. And they weren't the 650's. They also grenaded often.

[LARRY VALENTINE]

I saw a 53 Hat once many years ago for sale at the Ocean reef club owned by an elderly couple who had exchanged their DD engines with later and new Yanmars They had to add lead ballast! Larry Valentine