On Thu, 27 Oct 2011 21:33:58 +0000 (UTC), wrote:

On Thu, 27 Oct 2011 12:24:59 -0700, "Bruce L. Bergman (munged human
readable)" wrote:

On Tue, 25 Oct 2011 18:16:03 +0000 (UTC), wrote:

Greetings All,
I have a 12 foot aluminum boat that is rated for a 10 HP max motor.
I do have a 10 hp outboard but bone on bone joints in both wrists
makes it really painful to put the motor on. For years I have been
thinking about various schemes to put in a liquid cooled 4 stroke
inboard. One idea is to use a conventional air cooled flat head motor
that's been modified with a water jacket. I told Harold Vordos about
this idea and he had done it and it worked well. I mean the liquid
cooling conversion. He even had done it with a motor that was very
close to a 7 hp motor that I have and was considering. I have also
thought about using a 125 to 250 cc motorcycle motor. But these are
expensive and rev higher. I have several reasons for wanting to do
this project. Mostly I want a quiet power plant and a liquid cooled
engine inside some sort of housing seems like it would fit the bill. I
want 4 stroke mainly because I'm tired of putting oil in the water. I
also want reverse and am not sure what is the best way, at least for
me. The plan is to use a prop shaft that pierces the bottom of the
boat and a rudder. So the motor would be inboard as would the
reversing gear. Money is tight so don't suggest a Crosley engine. If I
could even find one for sale. Any thoughts?
Thanks,
Eric

Stupid question: Why not leave the boat alone (through hull = leaks =
that sinking feeling...) and just build a davit hoist at the dock and
modify a 4-wheeled hand truck for handling the engine?

You find yourself a really nice 10 HP 4-stroke outboard...

Then either take some steel stock and build a lifting yoke that wraps
around the housing and puts a hoisting eye right over the CG. Or you
pop open the little plastic plug on top of the engine (or take off the
top shroud) and find the factory lifting hole at the balance point,
and buy a lifting eye with the right threads.

Oh, and put a second eye on the side of the motor where you can clip
on a tag-line rope, with the other end attached to the dock - Just in
case the motor takes an unscheduled swim...

Davit hoist on the dock, that's a no-brainer of engineering. But
considering the proximity to water, I'd use a 12V winch and a battery
box so you just hit the "UP" button when you want to go, and you can
trickle charge the battery. Even a solar panel.

120V winches and GFCI's don't get along well, so forget that.

And you take (or make) a 4-wheel dolly with a bracket that looks
suspiciously like a transom, drop the motor on it and wheel it off to
the garage. Could even have space planned in for a plastic trash can
on it for flushing out the motor.

10" pneumatic tire casters if you'll be dealing with grass and dirt,
and humongous flotation tires and a "Radio Flyer" steer axle if you
have to cross sand.

-- Bruce --
Greetings Bruce,
If only I had a dock. Everywhere I launch the boat is from a ramp. So
I need to get the motor on and off while the boat is on the trailer. I
suppose I could build some sort of crane on the trailer. Takes the fun
out of building an inboard though. And doesn't address the noise. And
I would need to get a smokin' deal on a 4 stroke outboard. But at
least for now I could use the trailer mounted davit to put the Merc
on.
Cheers,
Eric


Seriously, can't you just leave the motor on the boat and trailer it
that way? Maybe make a hoist/engine stand on wheels for removing the
engine at home if you need to do maintenance on either the engine or
boat? Certainly the blokes with the three 150 H.P. outboards on the
back don't take the engines off to trailer the boat and I used to see
a lot of "fishing boats" with 5 HP outboards being trailered.

Sure, building a spiffy liquid cooled engine and all the fixins would
be fun but I'll bet that either, A. It won't be very serviceable, or
B. it will take a lot longer then you estimate to finish it.

I just had a look at small liquid cooled Komatsu diesels - all in the
115 lb. dry weight range. An air cooled engine initially seems lighter
but adding water cooling, water cooled manifold (although not strictly
necessary) and this and that may raise the weight to about the same as
the diesel. An air cooled engine with a water cooled exhaust with an
add on pump to supply the water would be the lightest and noisiest.
The air cooled engine would also be the hottest but as a liquid cooled
engine is running at about 200 deg. (F) it will burn almost as well as
the air cooled :-)

Nope, my suggestion is to leave the motor on the boat. If you feel it
hangs down too far to trailer then you could fit the sort of
retracting engine mount that they use on small sailboats that use
outboards for auxiliary power - Richard (cavelamb) can probably
describe them if he is reading this thread.

Nope, like the day job, I wouldn't throw the outboard away until I had
actually built, tested, rebuilt and made the revisions for the air
cooled motor design :-)


--
John B.