Stalyoni- Hey your set up looks like it will go good. The kv and battery combo is about right. 2 cell will be good for small surf and if you are in larger stuff you will probably like the 3 cell. what ends up happening is on 2 cell you will be gunning it harder and you will burn thru 4k mAh pretty fast. It also has a lot to do with the drag in your stuffing tube and the size of prop. about 28 to 30mm should be good.
The best is to have your ship tight from leaks but if you are taking on water I would put the receiver in a balloon. Best of Luck !!
Dom- Motivation to get my charging station in a metal box !!! The stink is the worst if you don't lose everything !!! I shot some old lipos with my pellet gun and seen the results
Aloha, KH