A few lessons learned during the builder's launch river trial in July2010:

 

 

1: some ballast in the stern is going to be required for 1- or 2-person loading; as can be seen in the following clip, the stern rides about 3" above the waterline. This is not unexpected, & I've been thinking for a while about how to arrange for about 80-90kg of easily moveable ballast to cope with 2 or 4 passengers

2: 15HP is definitely more than sufficient.  I'd estimate the speed here at about 8 kts (forgot the GPS on the trials) - but as I had little time for niceties like setting the throttle & tickover cables correctly, this was with the engine running at the top of its tickover range (probably about 2000rpm from a possible 4000). The wash was rising to the top of the engine well, so I may fashion a foam buffer to sit in the top of the well in case we ever have need to go any faster.  Other options would be to PX the 15 for shorter, prop exhausted 10hp, but I quite like the idea of "tickover+" being the normal runing speed for the unit, with the occasional blast to clear the tubes as necessary. This would also have the benefit of keeping the prop speed low & reducing the inboard wash problem.

Oh, to have had the time to set the throttle cable up...but it wasn't too cold in there

Benefits of a working engine  caution - scenes of an (almost) middle aged bloke in speedos may cause distress to some viewers

Again, the issue of ballast requirement is visible in the next 2 videos

but with 3 people on board, she sits very nicely, with little extra dip when underway

 

Other than that first engine stall on the way back in,  I think it's been a success :-))))) but, as with so many ventures, some essential help is always required:

 

without Rich, we probably wouldn't have got to the river, and without Mark, there'd be no record of events. Thanks Guys. Hope you enjoyed the spectacle & the visit to the Flowerpot afterwards !

 

Thanks also to a couple of real gents who offered their help with towing vehicles & trailers - Ian & Chris, you know who you are. In the end, I managed to muddle through, & the final run up to launch kind of overtook me, so I didn't have time to give you advance warning & invite you down as well.