Moe Zhoost

If your FIL means to be prudent and give way to larger vessels, then this may be a valid strategy to avoid collisions. On the other hand, there are a lot of small vessels with limited speed and maneuverability that do have legal right-of-way. Assuming that a big power boat is not in a limited special category, the operator is required to alter course. Failure to do this is criminal negligence.

Of course "right-of-way" is moot if you're dead.