i know this is an old thread but i thought i would post an update of how my boat performs now.
2 x S2858-2630 Brushless Inrunner (2630kv)
2 x Turnigy 3000mAh 4S 20C Lipo Pack
2 x 38mm counter rotating props
1 x 190-200amp hobbyking water cooled esc
1 x 5a turnigy ubec
1 x 3000 hkr rx
1 x hk 300 tx
2 x cooling intakes and 4 outakes
i have some better c rating lipos now and i will put dads old phone in it as use a speed app next time to get the speed.
I still have to add another pickup into it as it stops every now and then and im pretty sure its due to overheating. I have only flipped this boat once and when I did I got the esc wet and it malfunctioned so I replaced it and it works fine again.
I have been thinking about going to 6s with different motors but its almost flipping now and top speed and I dont want to add more weight to the nose to stop it from flipping. Im also limited to the space I have here. On a 6s it would chew it up very quickly.
I will stick in my old phone with a gps speed app in it soon and get a prop speed reading with my better c rating lipos and we will see what we get.
All I know is that its quicker then my dads boat and im happy with the way it runs now.