I'm guessing this is the boat?
[link=http://images.google.com/imgres?imgurl=http://www.gadgetgalaxy.com.au/Hobby%2520Boat6.jpg&imgrefurl=http://www.gadgetgalaxy.com.au/Radio%2520Control%2520Boats.htm&h=298&w=800&sz=95& hl=en&start=1&um=1&tbnid=4rbSeX31GM9U9M:&tbnh=53&t bnw=143&prev=/images%3Fq%3Dwild%2Bseeker%2Bboat%26um%3D1%26hl%3D en%26safe%3Doff%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-]boat[/link]

ESC

INCLUDES: Two Black anodized heatsinks (one small, one large) One Streak Speed Control Unit Motor capacitor kit (Only Two Capacitors Used For Speed Control, One Will Be A Spare) Double-sided mounting tape (1" x 1") One Schottky diode (silver line goes to Positive) Pre-installed standard type battery connectors Pre-installed bullet style motor connectors Pre-installed Futaba receiver connector Mounting and hook up instructions

SPECS: Voltage input: 4 to 10 cells (4.8-12V) ON-resistance: .004 Ohms Operating frequency: 3500Hz Maximum current: 300A Weight: 2.1oz Case size: 1.64"L x 1.5"W x .66"H Rx wire length: 10.5" Batt wire length: 4.5"

I would think that motor will be fine for the size of the hull. Since the prop will be subsurface you'll have to be careful when choosing. I think you actually made a good choice for a prop an x432 might be a good start. You probably will want to reshape the prop however since it is subsurface. The trailing edge gets modified like this.
I wish I knew a lot about modding the props but I know this is what the end product should look like. It is tough to find subsurface props and there isnt much info out there on them for FE's. Whatever you do, the prop needs to be balanced and I'd recommend buying a balancer to do it properly. Check out the hints/tips senction on offshore electrics website.