Hi Darren,
I would stay away from the amphungry FSD motors if I were you.
It's a two pole motor with a poor low end response, meaning you can't run it dead slow, as it 'll burst into life at one third throttle.
Also, 2075KV will give you 15000 rpm on 2S Lipo's, which is rather a lot on a subsurface prop, rule of thumb is not to exceed 10.000 rpm, to avoid having a blender under the hull (and little forward motion).
Not knowing the size and weight of your boat I can't make a suggestion which motor to get, but a four pole inrunner, or, even better, a multi pole outrunner will work nicely.
Check out the video of my 110 cm MAS hull, powered by an 800KV outrunner on 4S, turning a 60 mm two blade prop:
http://www.youtube.com/watch?v=-igDcvLySEM(Turn up the volume really high to hear the running noise.)
Regards, Jan.