fast DIY Personal Watercraft? (35-60kts)

I remember being fascinated with this design ever since I first saw it http://www.rqriley.com/hr.html which apparently can reach 40mph with just 25-30hp. With modern watercraft pushing 70mph i'm curious if anything faster has ever been developed for homebuilders, or if simply throwing bigger power on that design would be safe...

More than just raw speed acceleration is exhilarating too. Or the ability to tow a barefoot waterskiier behind it.

Dont think i'm too crazy - my original plan was probably just to build a couple of HydroRunners for me and my lady to have fun on which will probably keep us entertained for quite some time. I just wonder if there is anything to 'upgrade' to later if we find ourselves wanting more performance, or moving to the ocean and trying to be the chasecraft for some seriously hardcore oceansurfing friends, and whether more would be a bolt on big outboard or if it would require a different hull/DIY project entirely.



I have seen a handful of other homebuilt PWC in the past, none of which even matched the speed or performance of the HydroRunner. I'm looking for that as the minimum performance level of interest.

 

70 mph on one of those would violate anti-terrorism laws.

 

haha, please tell me you are joking... has the united states really got that crazy since 911?

As to my thoughts on the craft, i would like one. I have bookmarked the page and may order a set of plans at a later date.

 

I took a mini speed boat out once...there's a good reason why mini boats died out.

At least this seems to let you absorb shock with your legs when in rougher water or taking waves. In a canal or calm lake would be fine I guess.

 

Well the craziest personal watercraft are now up to 67mph from the factory (capable of faster but they call it a 'gentlemans agreement' to electronically limit it, the same way that motorcycles were limited to 186mph to stop the horsepower wars) and have up to and beyond 300 horsepower, 20 gallon tanks, and up to or even over 1000lbs. (Kawasaki Ultra 310X if curious) The deep vee hull lets you carve corners and slice through waves perhaps in a way the HydroRunner wont, being trimaran-ish.

I'm sure it's like the snowmobiles that now do 120mph from the factory and everything else. AKA when I grew up in the 80's what I thought was fast doesn't even register anymore.

I'm sure the HydroRunner would provide me years of fun - but at some point I might find myself wanting more. So i'm curious if anyone (even if this thread still exists 5 years in the future and hasn't been added to yet please post a response if you become aware of one!) has ever designed something faster.


There ARE a few other PWC plans out there - I forget their names - and they weren't that remarkable because they were all notably slower than the HydroRunner for like 12-18hp max whereas i'd like something that could pull a waterskier.

 

FYI even though I already had the last post, I just wanted to share that I think I lost interest in the DIY watercraft route...


Finding footage on youtube of the HydroRunner in action shows so much porpoising and a... well... lack of high performance turning (yes the micro trimaran seems stable side to side, but that means it's going around any turn flat so if the only fun is going forward and that already climbs towards the sky and bobs around...) that I think for the amount of effort to build it i'd be better off with any 2 decade old sit-down craft by which their vee hull designs was already letting you bank into turns nicely.

AKA I can see why they sorta died out of the market - hard to come up with something substantially better performing than a light vee hull with plenty of power and the safety of a jet drive.