View Single Post
Old 11-25-2008, 03:38 AM   #4
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 17,469
RE: How much power is enough?

If you are interested in a displacement boat about 3hp / ton of displacement is about all the hull will absorb.

Do not use USCG "tons" they are a volume not a displacement measure.

Many will power to 5hp per ton , on the assumption the load will still be nice and substantial at cruise speed .

There is usually NO reserve for current , you only go thru the water at the same speed for the same power.

Wind is a problem usually in docking , although the ability to proced in 40K can usually be done.

The big power absorber is CLIMBING waves , which can require 50% more power AT THE SAME SPEED.

Usually most folks do not proced when the G loads get over about 2.5G , so slowing down to climb the hills is the most common, not requiring additional power .

So a "proper" engine instalation will still be a nicely loaded SMALLER engine, rather than a Monster , for "just in case."
FF is offline   Reply With Quote