Hey Merdub, why not go with one 540 brushless rather than 2 180's. A 180 is SMALL. I used a 280 BL on my 3D plane and thought it was small.

Doing so will get rid of the complications of using 2 ESC's, 2 motors, 2 drive shaft or gearing, props ect. Not to mention the extreme lack of efficiency of vector thrust. For a hydro, using a rudder and a single prop is nearly a must.

Ryan