It is a old 3 cylinder Perkins, with a PRM 160 gear box, John Else at the boatyard just up from Trent lock, he seems very knowledgable on drive plates, he was the person that told me that the wrong plate had been put on, he showed me the correct one compared to the Herth and there was a obvious size difference in the middle in other words would have been loose on the spline, you could also tell on the spline where it was shiny where it had been rubbing. He wrote a letter for me, for the Insurers but the company that fitted it had almost gone bust so couldn't get my money back or anything