Vessel Not Under Command Overtaking: Which gives way?

There is one hypothetical situation which may need to
be debated: ‘a vessel not under command
overtaking a power driven vessel’. For
the purpose of this discussion, let us say
that this is in good visibility and both the
vessels are in sight of one another, ample
sea room and no other traffic.
Rule 13 says, ‘Notwithstanding
anything contained in the Rules of part
B, Sections I and II, any vessel
overtaking any other shall keep out of
the way of the vessel being overtaken’.
Under this rule the vessel overtaking is
very clearly required to keep clear and no
other rule of sections I and II of part B is
applicable. Thus in the given scenario, the
vessel overtaking (the vessel not under
command) should keep clear.

Excerpted from The Nautical Institute by Erik Pedrosa