Tonight I tidy up the back abit. I also start jet something.
I ran the basic calcs and covered prop can be OK, start around 90mm 5 blade with fixed stator. I decide to make the stator and nozzle on a large dual thread so can be easily changed or I give up and put open prop on.
chatGPT being told to be “professional hydronics engineer” helped alot with the quick maths.