[MHml] Engine power

[Martin Schöön]

On 2/3/07, roy mills <rsirfj at shaw.ca> wrote:
<snip>
>
>     Are you quite sure you want to go at 20 knots?  14 would be twice as
> fast and would only need provide about 4.5 times as much thrust instead of
> 10. Besides 90 hp is not as big a challenge to find.  You were concerned
> that a tall standing outboard would bang up against the underside of AB. If
> you did not use an outboard that height would not be a problem. Sure Diesel
> is heavier, but fuel is heavy too and you would burn a good deal less. Prop
> efficiency is the key factor in converting hp to thrust.
>
>     Cheers anyway   Roy, who looks forward to a similar blizzard of
> technical advice to what you got with your initial query.

I agree with Roy when he questions your need for 20 knots. High speed
is costly in terms of power (and fuel cost).

I have done some (w)reckless number crunching. The results are
summarised in a pdf-dcoument that can be downloaded at:
http://hem.bredband.net/mschoon/Modelling_Afterburner.pdf

-- 
Martin Schöön              "Problems worthy of attack
                                         prove their worth by hitting back"
                                         Piet Hein