Those jet boats look fun.
I have actually changed the engine since that day Ian, That was with the old 2.0 SST120 which I think made about 160ish hp, from top speed mph ish (as was never setup full race and had wrong exhausts and other bits) I have now fitted a Laser 220EFI (the same model but not the same engine as the one from the quantum). That's why I'm now running the 25p laser II, up from a 21p laser II.
I have not got a full top speed run yet as its gets a bit wobbly and need solid engine mounts, but so far clocked 62.6mph up from 56 on the old engine.