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looking for a new engine


amelmango <chiefnelson@hotmail.com> <chiefnelson@...>
 

Luis,
I think the calculation for hull speed is the square root of
waterline times 1.2-1.4. The varible factor is for a lower surface,
medium displacement sailing hull form. So for a Mango: sq. rt. of
41.5=6.5x1.2=7.8 kts to 6.5x1.4=9.1 kts
My old 80 HP 4-236 with a fixed 3 blade will make 9 kts in low
seas and 8 kts in medium seas. So, I'd guess that you'd be wasting
HP at anything over 100 HP. Like I said before, I'd want to talk
with the prop folks to what they thought of cranking in some more
pitch to cope with the increased HP.
Best regards,
Adam


Adam,
Thank you for your advice.Do you know which is the maximum speed
that this boat can reach considering only her length over water, and
what do you think about the convenient maximum horse power for the
engine.
Kind regards,
Luis