do I need a flexible coupling?

billcole said:

The installation instructions for the Vetus Bullflex say that if the propshaft has two rigid bearings you should remove a centering ring from inside the coupling, but if the only rigid bearing is the cutlass then the centering ring should be left in. Not sure how that relates to R+D couplings, but it does at least imply that some degree of coupling flexibilty is permissible with inboard end of the shaft not running in a rigid bearing.

If it's just spacing you need then ASAP supplies sell rigid bobbin spacers (also R + D ) to go bewteen the gearbox and the coupling

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Now that sounds perfect! I have to fit a new four inch flange to the shaft. My next move is to buy the new gearbox (prm 120) and bell housing and take this to the boat. I can see what spacing if any is necessary and as the bell housing has the rear engine mounts, get this welded so that the engine mounts line up with the old bolt holes in the bearers. After this, fit gearbox and bellhousing to engine, crane into boat and then make up front mounts to suit... If only it was as simple as it sounds!!

Now that sounds perfect! I have to fit a new four inch flange to the shaft. My next move is to buy the new gearbox (prm 120) and bell housing and take this to the boat. I can see what spacing if any is necessary and as the bell housing has the rear engine mounts, get this welded so that the engine mounts line up with the old bolt holes in the bearers. After this, fit gearbox and bellhousing to engine, crane into boat and then make up front mounts to suit... If only it was as simple as it sounds!!