islander 36 2:1 gear reduction;prop size

[Moltensurf]

hi everyone, my name is jonathan, I am the owner of a 1977 i36. I have a small problem, I let my zinc on the prop shaft go bad; now I am needing to buy a new prop. there is not a lot of info online about the subject. I have an atomic 4 gas engine with a 2:1 reduction gear.
I talked to the guys at indigo and they suggest a 12" prop with 12 degree pitch. that is on a three blade prop. I found a 2 blade prop online 12/10 but I was told this is not a good match for my boat, and and that I need something more like a 15", but i'm not sure there is enough clearance between my hull and the prop. is there anyone out there with some info that could be of help?

[ndutton]

If my memory hasn't failed me, the standard I-36 prop was a 16x10x[shaft dia] RH 2 blade. Standard boat was powered with the Atomic 4 with 2:1 reduction gear.

[Marian Claire]

Having gone thru the re-propping process on a non standard boat here are some links you may find of use.

http://www.moyermarine.com/forums/showthread.php?t=6148

http://www.moyermarine.com/forums/forumdisplay.php?s=&f=21&page=1&pp=35&sort=lastpost&order=desc&daysprune=-1

http://www.moyermarine.com/forums/showthread.php?t=6046

Be aware of the disclaimer in my first post on this thread about faulty tach numbers.

Short version is that a 14 X 9 three blade proved to be a good match for my boat. 12000 # displacement, 25' water line, 2 to 1 reduction gear with proper clearances in the aperture.
Welcome to the forum.
Dan S/V Marian Claire

Edit: You may also need to address the issue that caused the zinc and prop to be degraded.

[Moltensurf]

I have two quotes From different prop companies. One suggests 14/10 another 13/10. I have 8.375" clearance to bottom of hull from center of prop shaft.

[Al Schober]

My Tartan 30 has a 12" prop, and it only clears the hull by about 1/2". This hasn't been a problem. I wouldn't let tip clearance drive your choice of propeller.

[Moltensurf]

I found a 13/10 prop at a good price. I have room for the 14/10
Will one inch of prop make a huge difference?

[Moltensurf]

Well I guess I answered my own question
Changing prop size one inch or pitch by one degree changes rpm by 200

[Moltensurf]

Finally found an affordable used prop. 14x10 got it a Minnie's for 145.00
Thanks for the help.