Once we had returned to Bourne End I set about investigating the knocking noise coming from the transmission system that we have been experiencing at low revs. It appears to be from the PRM gearbox so I decided to remove it to investigate. I had checked the Aquadrive CVJ and fitted a new drive plate last winter so I was pretty sure it was the gearbox causing the noises. Once I had disconnected the Aquadrive from the back of the box it became apparent that there was a lot of play in the gearbox output shaft bearing. With the box removed the driveplate appeared fine (only fitted last winter) so I lugged the heavy gearbox home and set about finding out what the cost for repair/replacement was going to be. Gulp - Refurbishment approx £800, replacement approx £1300
The following Thursday evening, whilst doing my routine searches on Ebay, I came across a picture of what appeared to be Jannock's engine bay. Lo and behold - someone was selling a complete Kubota engine and PRM gearbox from another ex Black Prince boat because the engine smoked a bit and they had purchased an new Isuzu unit to replace it. I managed to win the auction (well within budget) and with assistance from my mate Don the complete unit was recovered from Newbury back to home. The gearbox fitted to this unit was a Delta 20 which is a lot smaller than the 160 that I had just removed from Jannock but Ken, the previous owner assured me that the gearbox was fine, just the engine had problems. I have fitted it onto Jannock's engine and am now awaiting the 4" bobbin that I need to fill the extra gap between the shorter gearbox and the prop shaft which I have sourced from TW Marine and should be here next week.
In the meantime I have done the figures for the 2010 cruising season:-
Total mileage 518. Total Locks 507. Total hours 277 Fuel used 348 Litres
that works out at 3.7 lock-miles per hour and 1.25 litres per hour.
More news about the gearbox and a test run soon - Watch this space.