Perkins Parama M30 torsional vibration. A plea for help.



My boat, a very heavy, very traditional, very wooden gaff cutter has an insatiable appetite for chewing up its Hurth 100 gearbox (two in less than 70 hours).

The engine and gearbox were bought as a unit just 3 years ago.

The supplier (who shall remain nameless, at least for now), says it is my fault because the gearbox shows classic signs of overheating due to lack of lubrication (well, they would say that wouldn't they).

I know this is nonsense, because I am always extremely diligent in performing routine engine checks and maintenance. In over twenty years of boat ownership, and another twenty of extensive cruising before that, I have never before experienced any problems of this nature (and, yes, I agree, I would say that wouldn't I).

I've sent the box to a highly reputable marine gearbox specialist who has stripped it down, and says that the box is showing classic signs of massive overloading. The damage caused by lack of lubrication would be very obviously different, so that is definitely not the problem here.

So there's something strange going on.

In my attempts to unearth the root cause, it has been suggested to me that the Perkins M30 engine, whilst looking, and sounding, to be a very smooth-running engine, does in fact generate very high torsional vibration, and it is this that is causing the gearbox to fail.

Has anyone else out there come acroos this problem? Has anyone come up with a proven solution that doesn't involve starting the re-engining process all over again? For example, is it possible to modify the flywheel? Could I fit a flywheel from the Volvo 2030 (which, I believe, is basically the same engine, but apparently does not have the same problem)?

It would also be useful to hear from anyone who has had years of trouble free use of this set-up.

Have any of the knowledgeable engineering types here got any other thoughts?

As some one who's lack of engineering expertise is well known, any advice or thoughts will be most gratefully received.