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Old 11-28-2012
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Re: Looking at a Alberg 35

Originally Posted by L124C View Post
As I recall Diesel HP isn't the same as gas HP. Is that true? If so, why?
Horses are horses. Horsepower is a calculated number, not a measured number - Torque X RPM divided by 5250 = Horsepower (which is the reason ALL engines torque and horsepower numbers match at 5250 RPM)

Diesel engines have flatter torque curves than gas and they produce their torque at lower RPM for the most part. That's why they feel like they have more "grunt".

Torque is a far more useful number than horsepower.

As a side note, if you can find out the RPM where your engine produces maximum torque, that is also the RPM where you will get the best fuel economy under load - ideally your prop should be pitched to run at that RPM at hull speed.
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