Actually, an engine ingesting water can cause it to self destruct. Someone mentioned hydro-lock before, and thats what can happen. Since water is essentially uncompressable, when a significant amount enters the piston bores, the engine will try to do what it does on every compression stroke, compress whats in the bore. Since water won't compress, usually what happens is you end up with bent rods and/or sheared wrist pins. Either way, it's time to throw out the motor. However, if the motor ran for a mile or so after hitting the water I would think this is not the case, and that the problem lie in the electrical system or starter.