Ooh! One other thing. You may have twigged from the water pickup pics that the test boat twins are gone. Following the final test run I inspected the engines and in particular I checked out the area around the prop driver. The test engines are both plain bearing, which means a floating crankshaft. So on the rear engine the thrust is pushing the crank in and only stops when the prop driver contacts the front of the crank housing. There's a thrust washer in there, I assume for electric starting, but it was looking a tad thin by now and so I've dropped that pair to save the engine. Engines with ball race bearings are different, they are axially loaded slightly when the prop is tightened, hence no end float so the bearings take the thrust load in either direction, it doesn't matter which way the thrust is going as the crank is supported the same either way, worth bearing in mind. I don't recommend using a plain bearing engine in pusher mode.
Interestingly, at least to me, I've fitted the test boat with the old MDS 40, a first export generation rough old thing that worked well enough some time back in the '80's but was never a keen performer. I thought I'd keep the test boat active for other tests, like the water pickup, and that it would be nice to try the MDS again to see how it got on with modern fuels. Off the top of my head, with the reduced weight and what seems to be more power than the twins coming from a much happier engine than I remember, this heavy test boat is about to take a bit of a step forward in speed. CoG is a bit too far forward now though, so we'll have to wait and see.
