Hey thanks Tophatters for the advice; And the illustrations live up to the picture worth a thousand words equation.
Not having dived or slipped I am now confident that it is another bit of the price I paid for running under load (for 5 ghastly minutes)with seriously out of line engine mounting.
But the good news is that up to about 2200 revs there is no noise and about 4 knots is good enough for me.
Soooooo This job goes onto the next time I slip her list with a caveat Skipper to the effect that no noise = no danger. sail a lot and motor quietly.
This weekend looks good for a trip down the Channel to Cloudy Bay-I'll post pictures
Thanks again!
tom