offset drive
 

Hello all.
I was wondering if anyone has any knowledge about installing an engine
15* different from prop. shaft. I'm hoping to drop the engine down
into the pilot house sole, so it's level. I'm considering "U" joints
or CV joints, or other alternatives that might prove better. I'm open
to any input. Thanks, Paul.

Universals are a source of friction (power loss) and possible vibration. Not
to mentions that they are not well suited to transferring the prop thrust to
the thrust bearing in the rev. gear. (the only vehicles that seem to have
extreme universal/CV angles are those radical off-road, monster trucks, etc.
and they have the power to waste).

You might be able to find a rev. gear that is built with this offset. Years
ago I remember something like this.. In the late '50s I installed a engine
with a Vee drive that had about a 15* angle difference between the input and
the output.

Steve
s/v Good Intentions


"Paul Baker" wrote in message
om...
Hello all.
I was wondering if anyone has any knowledge about installing an engine
15* different from prop. shaft. I'm hoping to drop the engine down
into the pilot house sole, so it's level. I'm considering "U" joints
or CV joints, or other alternatives that might prove better. I'm open
to any input. Thanks, Paul.

"Paul Baker" wrote in message
om...
Hello all.
I was wondering if anyone has any knowledge about installing an engine
15* different from prop. shaft. I'm hoping to drop the engine down
into the pilot house sole, so it's level. I'm considering "U" joints
or CV joints, or other alternatives that might prove better. I'm open
to any input. Thanks, Paul.

Suggestions:
(1) tilt the engine down a few degrees (i.e close enough to level that it
should still fit under your sole) +

(2) down angle gears are commonly available. Usually 10-15 degrees. Best
choice if you have not purchased a gear yet

More complicated:
(3) if the shaft length is long, 2 sets of cardan shafts (U-joint
driveshafts), each set absorbing 7.5 degrees of angle, with a straight shaft
in between. You would need to support the straight shaft with 2 pillow
blocks. You can purchase "short coupled" cardan shafts that have no tube
between them, just 2 sets of U-joints mounted back to back that are quite
short, about 12" long. Cardan shafts are quite cheap compared to most CV
joint solutions.


We do this all the time with tugboats with 3000 HP/engine, where the engine
is mounted low and the Z-drive input shaft is up high. Cardan shafts are
relatively cheap in small HP and will give useful life spans in the bearings
at these shaft angles if the engine hours are not too high. For a typical
offshore cruiser, figure 500+ hrs engine life / year; coastal cruiser, 100
hrs/yr. Ask for a B10 bearing life of 1500-2000 hours at 7.5 degees from a
cardan shaft supplier.

--
Evan Gatehouse
ceilydh **at** 3web **dot** net
---- rewrite my signature to send email

There is an article ( "Geared Up" ) on page 112 of the current issue
(Feb. 2005)of Passagemaker magazine that may be of interest. It is
about system to drive two props with one engine. 1/2 of the "Geared Up"
system may be adaptable to your needs

Rich A.