Hi Matty 40s, we are off the Ashby, up the Coventry/BirminghamFazeley and now on Trent and Mersey. No change yet! Might try the River Soar in a week or two and see how it goes then.
As stated in my original thread, its vibration/judder on the tiller arm, not vibration through the boat. Prop was been replaced a year ago and still has the problem. (Was the same with old prop). I think we can rule that out. Thanks for replying, will have to check if it is a large rudder.