CW,
(I used to live next door to a boat by that name.)

I fully respect right and desire to disagree, but the facts are that a
two ton sloop (that can actually sail) regardless of hull dynamics does
not even need the 10Hp to make hull speed in most weather you would
actually ever be in and if it is too rough for that, an outboard will be
out of the water half the time.

My boat came to me with a 7.5 and the only reason that I changed it to
the 9.9xles was for the electric start. The 28" transom height was just
nice to have in spite of the small additional weight. (I think nobody
make that 28" anymore.)

Yes, the high thrust version will always produce more thrust, but always
at the expense of crankshaft speed at cruise and always at the expense
of top speed (again this may not matter as you have achieved hull speed
at less than WOT). That additional engine speed must cause additional
fuel consumption (just like running in second gear).

By the by, since the Ford B block went away (1968?) all the trucks built
in this country have had engines that were common with the passenger
automobile production.

Matt Colie
Lifelong Waterman, Licensed Mariner and Pathological sailor


Charlie Morgan wrote:
On Mon, 12 Mar 2007 10:16:52 -0400, Matt Colie
wrote:

Shaun,
Basically Yes....
Your bet from here.
snip

Matt Colie

I respectfully disagree with this assessment. For a displacement hull,
the high thrust version is so much more suitable that I would not
consider a standard thrust model, even if it cost $1000 less. I would
not put a car engine in a dump truck, either.

You'll find out a Major difference when you need to motor against a 4
or 5 knot current. We can motor (Yamaha High Thrust 9.9) at hull speed
in calm waters, and carry on a conversation at normal levels in the
cockpit. At idle, it's almost completely silent. There's a big comfort
benefit. It also stops the boat very quickly. When people ask me how I
like my motor, I tell them it's like having my own personal tugboat
along.

Another factor is that the 9.9 High Thrust is available with a Xtra
long 25 inch shaft. For transom mounting on a lift bracket, that's a
big advantage.

CWM

Shaun Van Poecke wrote:
hi all,
Im trying to compare a couple of yamaha 4 strokes, both long shaft, both
electric start. the 15 and the 9.9 seem to share a common block, but with a
different carb and prop? they have exactly the same weight (50kg), same
displacement (323cm3), same compression (9.19:1), different gear ration
(2.92 for the 9.9, 2.08 for the 15).

is the 15 just a 9.9 with a different carb? are they just as reliable as the
9.9? Im guessing they wouldnt have as much usable thrust as the 9.9 with
its bigger prop, but probably a higher top speed?

thanks for any and all info,

Shaun




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