Saturday, 13 February 2010

Launch Day

The boat finally got wet at the end of October 2009. I was very lucky to be able to use a local lake to test the boat. The lauch went well and no leaks were found. After the naming ceremony (where she was named "Soap Dish") it was time to start the engine a go for a spin. The engine started on the button and everything seemed in order. Once she was warmed up, i took her out and tested the steering and then after tootling around for a bit, tried to get her up on the plane. It quickly became appartent that the jet unit had some major problems as the jet would slip as more throttle was applied. A quick burst of throttle only produced a load of bubbles, but did not result in any decent acceleration. To get the thing on the plane, i had to feed the throttle in gently, but there remained the sensantion that the jet unit was not running well and could be likened to the feeling of the clutch slipping in a car. The problem was put down to the tip clearance around the impellers (the distance between the impeller tips and the wear rings). After the run the jet unit was disassembled and the tip clearance was found to be way too big (about 2mm). The recommended tip clearance for jet units is about 0.2mm. I was aware the tip clearance was big but had not expected such a drop in performance and had deliberately left the tip clearance as it was to account for the small eccentricity in the shaft. The jet unit has now been removed and is undergoing a full rebuild with a new Duplex Stainless Steel shaft and new wear rings sized to give the correct tip clearance.

At the top of the slipway ready for launch!

In the water again, after years in the shed

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