Well there is good news and bad. IF, and that is a big IF, the engine power head didn't go under water, and the picture shows it sitting well above, then you have one less issue to worry about. The boat, of course, needs completely cleaned out as well as the tank like Scott Danforth stated above. And most of the wiring and gauges could be iffy as well. I would remove the batteries and dry them out and see if they still hold a chagre. But the engine shouldn't have suffered any issues if it stayed above the water. JMHO