[Rhodes22-list] motors

[Brad Haslett]

Bill,

MJM's got a point here.  Someone who is better with physics can explain all
this but for the max ooompth you need a bigger prop at lower rpm's.  To get
8hp out of an 8hp engine you need to run it wide open.  Getting 8hp out of a
15hp engine would be about 60% power and near the peak of the torque
curve, and, you'd be turning a bigger screw at a more efficient rate.
Nothing beats cubic inches! (that's what the girls tell me anyway)

Brad

On Sat, May 31, 2008 at 10:49 AM, Bill Effros <bill at effros.com> wrote:

> Thanks, Michael,
>
> So nice to hear your voice.
>
> B.
>
>
>
> michael meltzer wrote:
> > Bill get the Yamaha t9.9 high thrust, the issue you are having are not
> hp,
> > but getting the hp into the water, the  11 3/4 inch prop with the high
> cross
> > surface area turning slow (the 2.92 gear ratio) is what you need, have
> stan
> > use the long rails on the boat(i.e they go above the transom) and get the
> 25
> > inch version (it will give you more wave height).
> >
> > Ran it for years on the sound in gale warnings, all you need, the problem
> > when you get down to it is the Tohatsu is designed for a light planning
> > boat(i.e. a small high pitched prop turning fast, and changing it prop
> does
> > not help, the "size is constrained" and gear ratio is fixed), it will
> work
> > in claim days but pushing it is fails... not sure the 15 Tohatsu helps,
> > still wrong gear/propsize so you will never get the rmp's for the hp (it
> > only 15 hp when the motor is turning 5000+ rpm and hull speed will
> prevent
> > that or it will be "forming" up the water without doing much)
> >
> > -mjm
> >
> > Ps. What to waste some money on a remote kit on the Tiller?
> >
> >
> >
> > -----Original Message-----
> > From: rhodes22-list-bounces at rhodes22.org
> > [mailto:rhodes22-list-bounces at rhodes22.org] On Behalf Of Bill Effros
> > Sent: Friday, May 30, 2008 9:59 AM
> > To: The Rhodes 22 mail list
> > Subject: Re: [Rhodes22-list] motors
> >
> > Too Bad!
> >
> > The Tohatsu 15 weighs only 114 lbs -- 10 lbs more than the current
> > Yamaha 9.9, and about the same as earlier Yamahas that were ripping the
> > motor mounts off R-22s.  (I've gained more than 10 pounds since I
> > started sailing my Rhodes, and I sit in the back of the boat, too.)
> >
> > Stan can beef up our motor mounts.
> >
> > What do you suppose would happen if you put the 15 on an R-22?
> >
> > I'm roughly 35 statute miles from NYC.
> >
> > It takes me roughly 7 hours motoring each way.  (5 mph ((not kph) seems
> > to be the top sustainable cruising speed for almost any sailboat in the
> > 20-40 foot range as a practical matter.)
> >
> > Could I travel at 10 mph for 3 1/2 hours if I had a 15 hp motor?  Would
> > the boat become completely unstable?  Has anyone tried?
> >
> > Bill, you could have been the first!
> >
> > Bill Effros
> >
> >
> >
> > Bdunn1 at aol.com wrote:
> >
> >> I checked today; the only difference between the 9.8 and the 8 hp has a
> >> smaller carburetor and smaller air induction.   I purchased the 9.8.
> >> Bill Dunn
> >>
> >>
> >>
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