Towards Building a Steam Powered Outboard Motor
Posted: Tue Nov 15, 2022 2:57 pm
Building a steam powered outboard motor has been a really long term interest for me -- dating back a couple decades to the first time I read about Terry Williams Sprite engine. Since then I've built two lathes from scratch, an oil fired iron melting furnace and many other interesting projects, but never attempted the steam outboard. I bought Benson and Rayman's Experimental Flash Steam 20 years ago, Westbury's book, too, read them many times through and pored over decades worth of ME's for flash steam info. At 73, it feels like now or never, because I'm sure building something that works reasonably well is going to be a long process for me.
At the moment, I'm still thinking about it and finishing up house chores before winter (splitting wood, tractor winterization, mounting the plow, etc.). But I still can try to focus evenings on just what I should do for a project. Even after all this time, it seems to change every few hours that I do think about it! So I need to stop thinking -- I just have to start simple, with a small engine, and see what it does, and what I get. That will give me a better idea of where I want to go from there.
Here's some "in general" thoughts about what I want for a steam outboard motor:
I imagine something that can power my lightweight 1958 Crestliner aluminum 14' skiff for what I do with my family: camping, fishing and exploring. The boat doesn't have to plane, though that would be interesting if possible. Presently with family of three aboard, a Mariner 8 hp OB planes it fine.
On the other hand, reaching non-planing hull speed - say 5mph - takes maybe a .4 kW using an electric trolling motor. So for that situation steam outboard of 1 hp would likely be reasonable, but I'm thinking maybe 2 hp if caught out in conditions you didn't mean to be in, bucking a headwind.
I'm thinking cast iron for both piston and cylinder, since I can cast those myself, though I could go with aluminum piston and cast iron rings in a CI cylinder, or I suppose it could even be a steel cylinder if there was a reason for it.
Arbitrarily I'm thinking something around 2" bore and stroke. Single cylinder, single acting, enclosed crankcase. Poppet or piston valve inlet, cam driven, uniflow exhaust. Monotube, wood fuel.
But first I'm thinking about making a smaller stationary version maybe, 1" x 1" engine. It's important for me to actually start something physical. I can think about something forever, and it just becomes a rabbit hole of inaction. I want to hold in my hand a piece of metal in the shape of a motor, no matter how well it fits to my ultimate expectations. That's the real start.
At the moment, I'm still thinking about it and finishing up house chores before winter (splitting wood, tractor winterization, mounting the plow, etc.). But I still can try to focus evenings on just what I should do for a project. Even after all this time, it seems to change every few hours that I do think about it! So I need to stop thinking -- I just have to start simple, with a small engine, and see what it does, and what I get. That will give me a better idea of where I want to go from there.
Here's some "in general" thoughts about what I want for a steam outboard motor:
I imagine something that can power my lightweight 1958 Crestliner aluminum 14' skiff for what I do with my family: camping, fishing and exploring. The boat doesn't have to plane, though that would be interesting if possible. Presently with family of three aboard, a Mariner 8 hp OB planes it fine.
On the other hand, reaching non-planing hull speed - say 5mph - takes maybe a .4 kW using an electric trolling motor. So for that situation steam outboard of 1 hp would likely be reasonable, but I'm thinking maybe 2 hp if caught out in conditions you didn't mean to be in, bucking a headwind.
I'm thinking cast iron for both piston and cylinder, since I can cast those myself, though I could go with aluminum piston and cast iron rings in a CI cylinder, or I suppose it could even be a steel cylinder if there was a reason for it.
Arbitrarily I'm thinking something around 2" bore and stroke. Single cylinder, single acting, enclosed crankcase. Poppet or piston valve inlet, cam driven, uniflow exhaust. Monotube, wood fuel.
But first I'm thinking about making a smaller stationary version maybe, 1" x 1" engine. It's important for me to actually start something physical. I can think about something forever, and it just becomes a rabbit hole of inaction. I want to hold in my hand a piece of metal in the shape of a motor, no matter how well it fits to my ultimate expectations. That's the real start.