Performance potential of old Unlimited hydroplane concepts

[RatliffFranklin]

Many years ago Unlimited (Gold Cup) hydroplanes were built with twin engines and twin screws.

It would be interesting to see what kind of straightline performance might be available if current Unlimited designs were updated with these old concepts to give them some real horsepower, for example using twin General Electric T-64 turbines instead of a single Lycoming T-55.

Could a 300 mph prop-driven boat be possible?

[Dan Ellison]

300mph is possible, A T-55 that spins 15000rpm combined with a modern drag boat w-drive in my outrigger would accomplish that speed easy. We run smaller props and overdrive them with ratio's 2.30 up to 2.60. modern fuel engine at say 8000-9000rpm. Add 6-7000rpm to that with the turbin, and even with a small gear, say a 2.30 with 12x16 propellers with 20% slip=360+mph. Thats a concervative #.

[RatliffFranklin]

Originally Posted by Dan Ellison

300mph is possible, A T-55 that spins 15000rpm combined with a modern drag boat w-drive in my outrigger would accomplish that speed easy. We run smaller props and overdrive them with ratio's 2.30 up to 2.60. modern fuel engine at say 8000-9000rpm. Add 6-7000rpm to that with the turbin, and even with a small gear, say a 2.30 with 12x16 propellers with 20% slip=360+mph. Thats a concervative #.

That was my other question, whether just as much might be accomplished by putting a single turbine in a drag boat hull.

I don't know what's the case now, but at one time a surplus T-64 was cheaper and easier to find than a T-55.