posted by John Robertson on 17-Jun-09 at 08:41 PM
Thought I'd share some of the problems I had (and the lessons I learned) at the Loch Fyne hoverin a couple of weeks ago.
On the Sunday I managed to rip out a side-to-side flap on the rear bag skirt due to a silly oversight. When I swapped tanks (I have boat type quarter turn fuel connectors) I couldn't quite get the new tank connector to lock properly so i just left it. On the cruise back, the connection failed and starved the engine which instantly died. At the time I was running around 38mph on smooth water and the rear of the craft dropped like a stone - the hydrodynamic drag on the rear skirt must have been enormous and the rear inner attach strip gave way pulling a flap right out of the rear of the craft. All my own fault! If I had pulled the front vent brake the skirt would probably have survived as it would have forced the nose to plough rather than the back end.
On Tuesday morning during a rough crossing the outer side skirt attach strip started to come loose - I fixed it by using longer/bigger screws but I had problems all week in the very rough conditions all around the skirt. To handle repeated wave slamming, the skirt attach system needs to be VERY secure!
During the return trip on Tuesday I stupidly ran out of fuel on the water (check out the videos - it was an almost full throttle journey and I used 30 litres of fuel in only 14miles ). After swapping tanks, the engine wouldn't run properly at all and I suspected that some debris had been dislodged in the carb. After three rebuilds on the Wednesday it still wouldn't run properly (huge flat spot - it would idle up to about 2Krpm then nothing until it shot up to 3800rpm - undriveable!). I took a trip back home on Wednesday night to collect a replacement carb (7 hour drive!!). Fitted on the Thursday and it was much better.
On Sunday, whilst returning from Lochgilphead, the engine started cutting out for no apparent reason. We had a fairly stiff tailwind and there was some spray being blown back over the rear of the craft. Once back, the engine failed the hosepipe test (spray a hosepipe full bore directly onto any part of the engine and it shouldn't miss a beat).
The reason became clear - I had washed down the engine bay and engine before this trip using a proprietary engine cleaner and it had stripped the electrics of the protective coatings and also the alloy block/carb/etc leaving them exposed to salt water corrosion (the engine was covered in white powdery oxide).
The week turned out to be my worst for hover-related problems. I did get home every time, but it was a close thing at times. The causes of the problems were mostly down to stupid things I did rather than any issues with the craft design.
I was very impressed by the rough water handling of all of the craft present at the hoverin - I thought I'd experienced rough water before but this was at another level!. Take a look at around 1:15 in
this video clip for an example of the longer wavelength chop.