Prop for my diy SUP

Hello everyone,
Iam building my own diy electric SUP and i have an 2,8 kw motor with 170kv on 6s. Now i need an prop for max speed and i want to 3d Print it, what dimensions do i need? (SUP is 10.8 feet and i weight about 70 kilos)
Thanks!

Hello, what engine did you use?

An 6374 with 2,8kw and 170kv