Need to slow down F1 Electric tunnel hull

[runningman]

Already posted in general talk but here probably a right place.
Just got Dunlap 27 Tunnel Hull Electric ARTR with following:
1. Scorpion 1900 motor
2. Outboard unit (I think he said it's K&B)
3. Octura 440 propeller (3 blade)
4. Aquacraft ESC
5. 2 5000mAh Turnigy batteries

Previous owner said that the boat can go 50 m/h.
What would be a good propeller to slow it down till I get used to it? Previous owner suggested 38mm 2-bladed.
How about CNC Prop 38mm - 3/16" bore (http://www.offshoreelectrics.com/proddetail.php?prod=cnc-3814250)?

[Chilli]

I'd choose a smaller diameter in the same prop family. If you want to slow down significantly, maybe a 435. Or if you are running 4S voltage you could drop down to 3S (if you have a 3s pack). Personally I would just run it as is unless your pond is very small. You are going to have to back down on the throttle going into the turns and into any wind over a slight breeze until you get the feel for the boat. Remember any change in prop could require a change in set up so if the boat is set up well with the 440/3, I would just stick with it.