[C320-list] Alternator belt for Perkins Perama M30

[nibj]

As the title says, my 1995 C320 has a Perkins M30 engine.  The boat is new to me, and I have yet another plea for help (soon I hope I will know the systems and can stop bothering the list).

Anyhow the engine currently has a very thin (and cracked) alternator belt. It is roughly 6.4mm wide (or .25in).  It squeals and needs replacing.  After looking at the Perkins website for a 103-10 engine I ordered a belt that is 10mm wide (and 850mm long).  But the belt doesn’t seem to fit the crankshaft pulley.  It appears to be just a bit too wide and will not sit in the groove of the pulley (it looks like it fits the water pump and alternator pulleys nicely - although I admit I am not an expert on belts).

So my questions:
1) Is a Gates 6214MC AVX10 x 850 the right belt?  Should I force it into the pulley V? 
2) What belt do you find works?
3) Are their differences amongst the Perkins engine installed by Catalina such that special parts are needed?

Thanks for your time (again).

Peter