INTRODUCTION
The small steam engine, suitable for use in a hobby launch, is not something that is widely available any more. However, such machinery can be acquired with a little effort. Those with lathe and metal working skills might consider building their own. Those whose skills are more paper oriented can buy ready built engines from a small range of suppliers, or second hand through the SBA classified advertisements.

COMPLETE ENGINES
The shipping cost of steam engines is high due to their weight. Thus the following, rather selective, list provides widely spaced suggestions that may at least be on your continent:

Twin 2½" + 2½" x 3" - From Phil Moore (UK) - See SBA Members' Handbook

Single 3¹/₈" x 3¹/₈" - From http://www.bjorklundsteam.com in Finland. This firms offers a very pretty little engine that they first built to demonstrate their machining skills, but now find is a popular product in itself.

Various Strathsteam of Australia offer four different complete engines from a 2½" x 3" single to a 3" + 5" x 4" compound. Full details available at: http://www.strathsteam.com.

Various The Reliable Steam Engine Company in Oregan, USA, offers a range of sizes of engine from 3¾" x 2" single to a 7HP triple expansion engine. Full details at: http://members.pioneer.net/~carlich/RSE/RSEhome.html.

Various The Beckmann Boatshop in Rhode Island, USA, offers a 2½" x 3" single through to a 12HP twin steeple compound. Full details at: http://www.steamboating.net.

KITS AND CASTINGS
This list needs to begin with a couple of classic engines:

Stuart Turner 5A - Single, 2¼" x 2"
Stuart Turner 6A - Compound, 2½" + 4" x 3"
both available from Stuart Models in the UK: http://www.stuartmodels.com (There are suppliers of thses castings elsewhere in the world - check with your local steam boat club.)

The Wilkie Engine - This is an engine that was designed by an SBA member in the UK to complement the Affordable Steam Launch. Single 2¾" x 2¾". Full details available from: http://www.wilkiesteam.com.

The suggestions made here are for information only and do not constitute an endorsement by the SBA of any particular supplier or design. Other designs and suppliers exist. Caveat Emptor still applies!