We have a vetus shaft and PRM gearbox, The prop shaft goes through the existing coupling up to the face of the gearbox plate - thus if the propshaft can not go through the R&D coupling it would in effect extend our prop shaft by its (R&D coupling) thickness, though I do not know if this would be an issue (any comments anyone?).
Like Martin I would like to know how (assuming the shaft was extended by about an inch - the thickness of the R&D coupling), what effect pushing the prop back by an inch would have? I can't see myself chopping an inch off the prop shaft with an angle grinder in the engine hole. Can you imagine the mess?
For those who've fitted an R&D coupling on their boats, how did pushing back the prop affect the performance?
I'll have to look at my existing (non-flexible) prop shaft coupling. Perhaps the prop shaft can go further into it?
Edited by blackrose, 01 August 2011 - 09:04 PM.