Monday, 8 November 2010
Reasons to be Cheerful - Part 1
Back in April I wrote about having a new propeller fitted to Starcross. At the time I was very happy with it, but I've resisted the temptation to write about it since as it seems my early enthusiasm was, initially, misplaced.
I soon discovered that although it moved the boat along nicely - and stopped it even more nicely - whenever I increased the revs above tickover it was incredibly noisy - a phenomenon known as "singing" and caused by the interaction between the prop, the underside of the counter and the water in between.
To begin with it was a loud screeching sound (I thought at first it was a slipping alternator belt!) and although it soon moderated itself it was still annoying as, at times, it was making more noise than the engine itself!
On my summer trip to the Working Boat Gathering it "sang" all the way from Norbury to Braunston and nearly drove me mad. By the time I got there I knew something would have to be done about it. Simon at Norbury Wharf had three suggestions: Fit a new prop of a different design; Grind the blade edges of the current prop; or, as a last resort, re-fit the old one.
The new prop - an Axiom - would be expensive (I've since found out just how expensive); grinding the current prop would involve docking fees and was not guaranteed to work; and re-fitting the old one would just take me back to square one, albeit several hundred pounds lighter in the wallet. I had until I got back to Norbury to decide!
The prop sang all the way from Braunston, down Stockton Brook and Itchington Locks, back up Hatton, and all the way along the Northern Stratford. It was driving me round the bend, but then - just as Duncan turned on to the Worcester & Birmingham Canal at King's Norton Junction - the singing stopped! Just like that!
On the rest of the journey back it would sing to itself now and again but with diminishing intensity and frequency. On my recent trip up to Manchester it hardly made a murmur and, although I realise this is tempting fate (!) I am taking it as yet another example of a problem solved by the simple expedient of putting up with it and hoping it will go away. As the bus drivers I worked with in Manchester many years ago used to say when confronted with a strange engine noise on the fifteen-year-old buses they drove used to say:"It's just 't newness, it'll wear off!"