Brushless Motors
It is hard to recommend a system that will work for you but I can tell you what I have and it works well with a 34" Crash Tender.
My setup consists of a mega motor:
http://modelfireboats.com/sys_files/images/MB36-4009.jpg
Spec:
http://modelfireboats.com/sys_files/images/BrushSpec.jpg
And a Barracuda ESC:
http://modelfireboats.com/sys_files/images/ESC.jpg
The whole system works but I did get this a few years back, since then the prices have dropped for speed controllers. it used to be near enough Impossible to get an ESC that does reverse but you shouldn't have any trouble now.
Just have a look around the internet, it is always a bit of luck with what you get but a few pointers would be:
Make sure the motor has a good amount of torque
Don't fall for the "Reverse Compatible" trick on the ESC's sometimes this means you have to manually swap the leads.
Hope this helps,
Fireboat 😎