Ocqueteau 645 Speed

[Jim@sea]

I am looking at an Ocqueteau 645 with an 50 Hp Nanni Diesel Engine.
Can anyone advise at what speed it will do, I am assuming 12 knots.
Would really like to know please.
I know they also do bigger engines

 

[Baddox]

The 645 with a 115hp Nanni engine would need about 2000 to 2200 RPM to get to 12 knots when it started to plane. Wide Open Throttle was about 2600 RPM and gave 20 knots.
So, a 50hp flat out on calm water may push a lightly loaded 645 up to12 knots but that seems optimistic and won’t be in a happy sweet spot for speed, revs or planing.
The 645 is a great boat but a 50hp engine in it would be frustratingly slow.