Hi
I'm building a boat from scratch and i'm thinking of putting a brushless motor in, but i don't know if i need to buy a speical speed controller?

Dr.x,
Yes, you will need a 'special' ESC for brushless motors, the common ESC for brushed motors won't work. Not being familiar with brushless motor requirements I can't help you there. The only thing I can say for sure is sit down before asking the price... Good luck.
- 'Doc

i think novak has a combo you get a 5800 kv motor (550 size) and the speed controler for like 150 bucks and it runs on 6 to 12 cells