My old ysb8 yanmar on my light weight 26' British built Trapper 300 finally
bit the dust last fall and I managed to find a used 1gm10. The old yanmar's
output rotation is opposite of the new one. The old propeller was a LH 11X10
two bladed bronze type. The engines are nearly the same in output. Would a
12X8 RH two bladed prop be appropriate? (an extra inch in diameter would
still clear the hull) Would there be availability problems finding an 11
inch prop...

Any thoughts would be appreciated

There is a rule of thumb about prop clearance but I forget it but you
can probably google it. I think that with a 2 blade that can be
aligned with the keel, you should use the largest prop that will allow
this clearance.

From Dave Gerr's "The Nature of Boats:" Ten percent (of the prop diameter)
is the bare minimum (tip clearance). 14 to 18 percent is the standard ideal
distance though bigger is better. High speed planing hulls should have 20
percent. Fair the edges of the prop aperture.

He also discusses propeller sizing and other factors.

Roger

http://home.insightbb.com/~derbyrm
wrote in message
oups.com...

There is a rule of thumb about prop clearance but I forget it but you
can probably google it. I think that with a 2 blade that can be
aligned with the keel, you should use the largest prop that will allow
this clearance.

Is there a problem with the old prop? Why not just switch the "F" and
the "R" on the gear shifter?

Well you said any thoughts.



Ed wrote:
My old ysb8 yanmar on my light weight 26' British built Trapper 300 finally
bit the dust last fall and I managed to find a used 1gm10. The old yanmar's
output rotation is opposite of the new one. The old propeller was a LH 11X10
two bladed bronze type. The engines are nearly the same in output. Would a
12X8 RH two bladed prop be appropriate? (an extra inch in diameter would
still clear the hull) Would there be availability problems finding an 11
inch prop...

Any thoughts would be appreciated

Some times you can just flip the cable mount to the other side. What was a
push becomes a pull.


"Richard M. Geis" wrote in message
news:momdneN9Mr9ZyGzenZ2dnUVZ_tOdnZ2d@cablespeedmd .com...
Is there a problem with the old prop? Why not just switch the "F" and the
"R" on the gear shifter?

Well you said any thoughts.



Ed wrote:
My old ysb8 yanmar on my light weight 26' British built Trapper 300
finally
bit the dust last fall and I managed to find a used 1gm10. The old
yanmar's
output rotation is opposite of the new one. The old propeller was a LH
11X10
two bladed bronze type. The engines are nearly the same in output. Would
a
12X8 RH two bladed prop be appropriate? (an extra inch in diameter would
still clear the hull) Would there be availability problems finding an 11
inch prop...

Any thoughts would be appreciated