Flexible coupling in prop shaft

[john daley]

A friend of mine who has a much larger boat was taking a look at the prop shaft where it leaves the engine and was concerned at the amount of movement displayed when the boat was put into reverse or forward gear. He said I should consider putting a flexible coupling in to lessen the wear on bearings etc. My diesel engineer says thats nonsense and it doesn't need it. Anyone done anything like this with their prop shaft??

[Roc]

John,
I have a Federal Flexible coupling that looks like this (see link below).  Definitely worth the price.  It really helps dampen any vibrations.  Having something flexible between the gearbox and shaft just makes common sense because a boat is not a totally rigid structure.  I believe there is some movement, and something needs to give.  

Regards,
Roc-

http://c34.infopop.net/3/OpenTopic?a=tpc&s=508296417&f=318296417&m=9902993276&r=5482915276#5482915276

[Tweetybd]

Roc,

Where did you buy the Federal coupling?  I also have a PSS dripless shaft seal, and am concerned about clearance.

[Roc]

Jon,
You are right about the clearance.  I originally asked the yard to install a Vetus coupling, but according to the specs, it wouldn't fit.  They suggested about this one.  I don't know where they got it from, but maybe you can search the web.  Also, in my email above, I have the contact info about the yard that sourced the coupling and did the installation.

Roc-