[MHml] HP to Watts

[Graeme Sutherland]

    The trouble with going from an electric to a diesel motor is that power 
is measured at different places on a power curve.

    A diesel engine is rated on its PEAK POWER, which is obvious if you look 
at the power curve.

    An electric motor will be rated on its DUTY CYCLE, which is the amount 
of output it can sustain. Sometimes this is based on a one hour run, other 
times it's more open ended. Electric motors don't have a peak power rating 
as such, rather it's the point where they burn out due to being fed too much 
electricity. However, it's peak output is likely to be two or three times 
its rated output.

    Hence the claims that electrics are three times better than diesels.

    The power output of an electric motor matches propeller curves better 
than a diesel, and having full torque from 0 RPM also means that larger 
propellers can be used. So there are some advantages.

    I don't know the exact rules for doing a conversion, but contacting a 
designer with experience of electric boats would be a sensible first step.

        Graeme