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

Bonjour Maxwell,
I had not realized your steam plant was so huge 

Never mind, my Suart D10 are able to push or pull a 450 kilos launch : so no problem for your launch with your 5A.

The last important thing you will have to manage is the propeller. Too small, it will cavitate and your steam plant will loose power and steam, too large and your steam machine will toil unnecessarily.