Prop shaft couplings.

[Skipper599]

On the subject of Prop shaft alignment, I too have a question.
My 1" shaft is relatively short eg: approx 24" driving a 13" x 3 blade prop. ... I've been wondering about the need for a "self aligning coupling" or whatever name you want to give such a device designed to reduce or eliminate vibration caused by minor misalignments.
I know for a certainty my motor and shaft are well within manufacturers alignment tolerances, but I'm wondering if a soft coupling will provide additional worthwhile benefits re: vibration damping?
These coupling devices are certainly not cheap. Are they really worth the added expense? ... I welcome any, and all opinions on this question.

[Tim]

If you're talking about one of the complicated couplings that are specifically designed to deal with misalignments, like Aquadrive or some of those indecipherable things from Vetus, then no, they are not worth it for your situation.

If you want a sacrificial disc (i.e. Drivesaver) designed to connect between the shaft and transmission couplings to protect your transmission or maintain 100% galvanic isolation between all underwater metallic components (if you're in the no-bonding camp), that's fine, but this isn't the same thing by any means.