On Tue, 08 Jan 2008 18:55:46 -0800, Jim wrote:

Wow, hull speed into 25 knots of wind. That's a lot of power.

Of course it isn't. Remember, power required varies with the cube of
the speed, and hull speed just isn't fast. I figure maybe 100 HP for a
thirty foot boat. Maybe less.
It's the fifteen horse motors I object to. Battleships won't do hull
speed on 1 to 4 HP per ton either. I am guessing you can get
three times what is average, for not too much space and weight.

It would be impossible to power at hull speed into a 25 knot wind, and
the seas that much wind kicks up.

Of course it is possible, it just takes sufficient power. You can get
500 HP out of a ton or so of diesel machinery. Many modern engines,
Yanmars for example, put out more than one HP per cubic inch. It is
certainly possible and the fact that most boats won't do it is rather
the point of my post. I figure you can live with a ten percent mileage
penalty with the bigger motor.


If there is enough room for large waves to kick up, you can generally
sail. I had in mind up a narrow river channel against wind, current,
and tide. Places like the inside passage to Alaska, more motor might
be handy.

I have done lots of sailing, not cruising, in more than 25 MPH of wind
and 2 to 3 foot waves. I used to launch a Sunfish off the beach into a
25 MPH wind. You waded out to where the water was deep enough to lower
the daggerboard. And on the return I would just run it in with the
board out. The rudder would kick up like a centerboard. Sometimes got
it up three or so feet past the waters edge, if I timed a wave just
right. Same lake had some 25 MPH sailboats: scows.