Have been interested in designing and building all kinds of steam-powered models for many years. Always wanted to do a small steam launch -- something in between an Elliot Bay and a large model that two persons could comfortably manage. Last May, I started a project to build a 13.5-foot fiberglass/mahogany launch powered by a home-brewed 2-cylinder, double acting 2" x 1.75" vertical engine. Boiler is coal-fired, 22" x 8" dia. with 45 3/8" (.5" o.d.) fire tubes. Just finished the engine and boiler and ran the first test (shown in attached photo). Other than a couple minor plumbing leaks, everything performed nicely. Although I designed the boiler just barely big enough to continuously run the engine flat out (to keep the weight at a minimum), it made steam to spare fueled with good old Welsh steam coal. This winter, I'll be gutting a fiberglass sailboat hull (Flying Junior International) and redoing the interior and decking in mahogany and teak. The boat has a nice wide beam and plenty of room for the engine, boiler, and auxiliary gear and a crew of two adults.
Hope I've figured out how to post photos here
