One boat is overtaking another. Which boat must give way?

Overtaking takes place in the various circumstances by the most opportune time that is advisable it is when there seems to be emergency cases. In this type of cases, the medics are usually given way so that they can go and attend to the victims of a given accidental occurrences. Also, the police are also given the first priority during pursuits, this is normally required of people so that they don't obstruct justice and also to clear the path so that the officers can carry out their roles maximally.

The boat that being overtaken must give way.

In this case, if there could be an emergency reason why the overtaking boat has increase its speed (such as medical or scheduling emergency). To prevent any potential damage or clash, it is better for the overtaken boat to make way and let the other one pass.