Well the first thing you need to bear in mind, is that a 3000 KV motor is going to wind 36000RPM on 12 volts, assuming the battery can supply the necessary juice, which is unlikely from a gel battery. Lipos will supply the required juice provided they're of the correct C rating.
On a 55mm prop, which is probably going to be in the 1-1.4 pitch range, you're looking at over 50mph with 25% slip on the mildest pitch.
Doubtful it'll do that, but the motor will have a good try at trying to, and pull a tremendous amount of amps in the process. I don't think the hardware in the boat looks upto the task, and those chocolate block connectors are likely to be a source of problems.
The 1000-1500KV range I mentioned before was much more suitable for this type of boat, and would have provided ample performance. The motor shown in the install will need to geared down about 2.5-3:1 or run with a smaller prop (less efficient) e.g. 30mm.