Noob needs some help

[SittingDuck123]

Hi all,
I’m currently scratch building my second rc boat using fiberglassed balsa wood. I’ve chosen my electronics: 2100kv motor, 120a marine esc, and 4s lipo. My only remaining issue is that I’m completely lost when choosing props. I understand the basic effects of pitch and diameter from model airplanes, but I don’t know any benchmark prop specs for my setup. If I can find out a benchmark prop, I’ll buy a whole bunch with similar specs and test which one works best. So do you guys have any ideas? I’m hoping for some decent speed (40mph ish or maybe more). Any guidance asap would be massively appreciated!

P.S: the boat is about 600mm long, here’s a pic of the hull in it’s current state (I’m fiberglassing it at the end)

[SittingDuck123]

Well, for some reason I can’t post the pic. Oh well

[dethow]

An Octura M440 or maybe X442 would be a good starting point.
My first thought was an M445 but that might create a little to much speed for that size hull. That prop would probably get you into the 50mph area.

I guess it kind of depends on what you want to do with the boat.
Sport boating at safe temps... the M440 will probably put you close to 40mph, the X442 will get you to 40 or maybe slightly above.
Racing or straight away speed... the M445 or M545 will probably get you to 50mph or above. You will need to watch temps with the M545 if the boat runs wet. Wet meaning: a lot of the hull in the water which creates more drag.

[SittingDuck123]

Great, thanks man. i’ll give that one a go

[dasboata]

what size shaft are you using ?

[NoBiffBetter]

Hey guys what would be a good upgrade prop for the impulse 31 v3? I plan on staying with 6s for now. I would like to be around 60+mph instead of stock 50mph average