Mercruiser hp rated at propeller shaft+

[enn858]

Hi - i have 2 questions:

Are Mercruiser and Volvo i/o`s hp rated at crankshaft or Propeller shaft?

How much loss do you have in eg. an Alpha drive?

 

[Haut Medoc]

Re: Mercruiser hp rated at propeller shaft+

1) Depends on the year.....
2) I'll leave that to the technical experts......​

 

[enn858]

Re: Mercruiser hp rated at propeller shaft+

Hi

What year did they go from Crankshaft HP to Propeller shaft hp ratings? (i guess they are Propeller rated today?)

 

[Haut Medoc]

Re: Mercruiser hp rated at propeller shaft+

I want to say in the 90's, but there are some member's who know exactly when...
Today they are rated at the prop......​

 

[Destin]

Re: Mercruiser hp rated at propeller shaft+

1990 is the first year they were rated at the prop, about a 10% reduction.

 

[enn858]

Re: Mercruiser hp rated at propeller shaft+

Thank you for your answers - Iboats are famous on our small Scandinavian boat forum at www.baadsnak.dk - the question came up - and when we need expert adwise we always ask you guys at Iboats.