Welcome. Just look at some of the build articles on this site and you will see many examples. For example here's one:
www.modelgasboats.com/Magazine...s/Rampage_Mono/
Basically, you drill the transom and pass tube through. Then you support the tube close to the engine, either using a bracket system (commonly referred to as "T-BAR") or make a wood "shoe" under the tube and glass it all together to the hull.