Shim the prop-shaft flange by 1/8"

Sep 25, 2008
CS 30 Toronto
Hi folks,
I need an extra 1/8" between the propeller hub and the cutlass bearing face in order to put in a rope cutter disk. I need a gap of 1/4" for water to cool the cutlass bearing.

Without replacing the shaft, I wish to put a shim disk between the shaft flange and the tranny. I'll have a machine shop to make me a flat shim ring for this. I can still align the shaft since the shim is machined flat.

Has anyone done this before? Need your opinions.
May 20, 2016
Catalina 36 MK1 94 Everett, WA
I believe that Spur sells a 3/4" spacer exactly like you are talking about for this purpose.

Nov 6, 2006
Hunter 34 Mandeville Louisiana
The shop needs to put a "pilot fit" onto the shim to hold the coupling on center.. a simple flat shim will have the shaft and trans output slightly off center.. The shim would have to have a raised ring on one side and a recessed ring on the other side of the shim to accept the ring of the coupling fit.. if ya have a good drawing of the coupling, a good machinist would not have a problem making one ..