"A few of us were racing together down the straight probably doing around 155mph (249.4kph) when one guy got into trouble and I ended up on top of him. He ended up doing three or four barrel rolls on the corner and I went in backwards," Lupton said.
"He was knocked out and rescued by the medics, but was okay later on fortunately. It happened pretty quick.
"The boat is going well, but not as well as we would like, although with each race we are gathering data toward our main goal - the main one is at Valleyfield in two week's time on July 14-15. That's the Mecca of hydroplane racing, the Daytona of our of sport or the Melbourne Cup."
At the weekend just gone Lupton won his first race and came second in the next to get the inside pole position for the final, Unfortunately, the motor got wet and the engine stalled, so he didn't complete the final.
On social network Jack Lupton suggested everything was back on track following the weekend's mishap.
"We have the boat off the trailer in Bert Henderson's shop (Canadian boat builder and series rival), Jaime Auld (arguably the best boat builder in North Aemrica), Warwick and myself have re-weighed the boat and are going to make some more changes.
"Jaime's fixing the sponson after coming together with Ghislain Marcoux in the GP444 down the straight. The weather at this stage is looking absolutely beautiful for the weekend, really looking forward to getting back on track. Fingers crossed the changes we make send us in the correct direction," Lupton said on facebook.
The Lupton team are used to racing far more powerful machines with engine size not restricted in New Zealand, while the HRL series engines can be no bigger than 468 cubic inches pumping out anywhere between 1350 and 1450 horsepower.
At home the Luptons are used to 510ci machines producing anywhere from 1600hp to 2500hp.
Whanganui-based engine-building legend Grant Rivers and good mate, Waverley dairy farmer Grant Gulliver, were expected to travel to Canada in time for this weekend's 1000 Islands Regatta at Brockville, Ontario.
The trick is to extract the most power possible from the restricted engine sizes and that will come down to the considerable talents Rivers brings to the mix.
"Grant Rivers is our key. What Grant can do with motors is legendary," Lupton said.