Steam Hydroplanes
By Rick Benson

The following three pictures were taken in 1995 but no major changes have taken place, since then, not visible one's anyway.
A brief outline on Model Hydroplanes:
They are used on a circular course, and are tethered, to give a 100 metre lap. A line from pole attaches to bridle, the bridle being about 4 ft long, fixed to two point on the hull.
The boat is started and launched with the aid of long "Bungee" which gives it a yank to help it get away. (this is a Bulgarian invention, would you believe, developed about 15 years ago.
Once, or more likely if the boat gets away and up to speed, the operator signals and 5 laps are timed (500m) and the time converted to MPH. Note no radio control or any form of control, they just run flat out.
Most boats are i.c engined and there are classes for 3.5cc 6.5cc 10cc all using commercial engines. Then we have two British classes "B" 15cc home built or steam under 9 Lbs total weight and "A" 30cc home built or 16 Ibs. Bob's boat is in the A class.
The fastest British record of any size is for 10cc at 135MPH. But Bob broke his own record several times this year (2005)the last run being 120.79 MPH. The flash steam Hydroplane is a pretty ferocious thing that is relying on burning a large amount fuel very quickly. In an old Model Engineer I think the efficiency was estimated at something less than 2 %. Bob has 3 burners on the blowlamp assembly with the boiler consisting of 30 ft of 1/4 " stainless tube. It really is very exciting seeing one of these hydroplanes operate, sheets of flame out the back , screaming engines, I have been brought up on this hobby, so my view is probably somewhat skewed.
My Father and I, are concentrating on 30 cc I.C. engines at the present, and unfortunately our speeds are not up at these heady heights. The above achievement is really remarkable. It is a strange hobby as one spends a long time making the thing and very little time running it. They often do not go, going for high speed makes for a touchy beast, you often break something and also there are fewer and fewer places where this can done. I am afraid our club numbers are falling too, in fact many exponents are 2nd generation some 3rd.

The next three pictures show the 120mph steam powered Hydroplane built by Bob Kirtley

Launching the hydroplane for another tethered run

seen here at high speed

The next two pictures are of Ian Berne's hydroplane

At high speed

The works

And here two pictures are of John Benson's hydroplane