I wanted to show everyone a k-boat a built a year ago. It's 38" long and has a OS 46VRM in it. I learned a lot about mold making and casting. I had a lot of fun last year driving it and looking forward to getting more out of it this year. I'm hoping the pictures attach.
I heavily modified a driver with clay and made a rubber mold. From there I cast the new driver. The material I use works well and also floats. He has flown out of the boat a couple times. Lol.The same process was used for the mock engine and fuel tank. Yes I am using the same OS engine you described. I may be interested in your engines. Let me know what you would want for them. I have thought about selling these boats. There are a couple minor things I would like to improve after building the first one to make it easier to build. Example how the mock engine mounts in. When I get home from work I will post a couple more pics of the inside of the boat.