Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

  Very ambitious.  I salute your confidence and encourage you to make
your dreams come true.  But please, remember, it is a hobby, not a job.

  So, first off, search the web to find out what is out there already
designed for your purpose.  No sense in re-inventing the wheel, you
will be busy enough as it is.  Are you designing the boat from scratch?
That would be much easier than designing a well-running steam engine
(and boiler and heater) from thin air. 

  You could buy plans, get the materials suggested, and do the machining
yourself.  Or, buy a set of plans with a casting kit.  Maybe a set of
plans with a machined casting kit ready for construction (my speed).  Try
not to make your first project too complex - I speak from experience.

  The only kit (a generator/motor) I built came from PM Research.  They have
a number of different engine kits, machined or not, that are well designed.
I already have a #1 w/vertical boiler/water-ram and a #7 kit (yet to be built).

  There are other kit suppliers, you just have to find them.  Also, there is
a 'Model Steam boats group' on face book/meta whatever.   

I'm sure your inbox will fill quickly,
Wayne