I've just gotten permission to use a couple of boats in my local area at different lakes.

But no engines, so I'm looking for a cheap engine solution..

On ebay etc. I see RHINO R - VX 54 can be bought cheap, but how well will it push a 14 foot 130-140KG model Crescent 405

Looking on youtube I mostly see inflatable boats and lightweight boat 70kg+, so I have hard time judging how fast it will go..

And what can I expect of running time with a EXIDE DUAL ER350 12V 80ah battery?

Thank you.