Building a Fast Steamer

I have a 14 ft Javelin Sailboat Hull, that I converted to inboard electric drive about 5 years ago.

This build is detailed at http://groups.yahoo.com/group/electricboats/ The build is found in the "Files" section under "Building an Electric Javelin"

The boat has worked well, having about 5 MPH speed with about 4 hours endurance at full speed, about 24 hours endurance at half speed, with 4 adults onboard. I built the boat so I could run with a steamboat group in my area while my traditional steamer was building. The Electric Javelin works well, keeping up with the slow traditional steamboats in the Philadelphia area.

Now that I have a larger steam sidewheeler working, I no longer need the electric boat, so I am thinking of making the electric javelin into a fast steamer. I figure about 10+/- horsepower and about 15 knots. I would prefer to convert a Thistle Hull (anybody know of a fiberglass one available with bad sails, broken mast, etc?).

I know I can make this steam machinery, at about 500 pounds total weight, or less if necessary. That would allow one or two people on the fast steamer with easy seating.

Any comments are welcome.

 

That is a pretty tall order! my father in law is building a steam launch she is a cedar strip replica based on a 1905 Saunders launch, 28 ft x 5' 6" beam.
Her engine is a 10 Indicated hp leake compound coupled to a modern yarrow watertube boiler. Designed working pressure is 180psi. We reckon the best she will do is somewhere around 9 knots.
Weight as ever is the killer. If converting a sailing dinghy like a Thistle your speed would also be limited by the hull shape & rocker.
Most fast steamers use enclosed sump high pressure engines revs with a flash steam boiler fired by parrafin (kerosene).
It would be worth joining the Steam boat association, http://www.steamboat.org.uk/, as they have much archive material on this subject, one member who lives in Australia has been developing a fearsome steam powered hydroplane for years.

 

Yes, a flash boiler with an enclosed single acting engine is planned. The Javelin hull is a planing hull, with virtually no rocker in the stern. I think most small racing sailboat hulls are of the planing design?

 

The javelin will be very weight sensitive and you may never get it to plane with the weight of a steam system. The Thistle is a wonderfully competant sailboat but it is not fast under power.

Several years ago I converted a derelict Thistle to a beach cruiser. I used a 9.9 HP Johnson two stroke ( a 15 in sheeps clothing) to little avail. The boat was delightful at speeds less than 7 MPH but resisted any effort to make it plane. Yes I did get it "up" a time or two by moving weight very far forward, wherupon the ride quality was most undesireable and the spray pattern extreme. Four HP would have been plenty for this application.