Final answer:
When two powerboats meet head-on, neither is the stand-on vessel; both should alter their course to starboard to pass on the port side of the other, effectively acting as 'give-way' vessels according to Nautical Rules of the Road.
Step-by-step explanation:
When two powerboats are meeting head-on, neither is the designated stand-on vessel.
In nautical terms, the 'stand-on' vessel is the one that has the right of way and should maintain its course and speed, while the 'give-way' or 'burdened' vessel is the one that must take early and substantial action to avoid collision.
According to the navigational rules commonly known as the 'Rules of the Road', when two power-driven vessels are meeting head-on, both are required to alter their course to starboard (to the right) so that they pass on the port (left) side of each other, similar to vehicular traffic.
This means that both boats are effectively the 'give-way' vessels and should take action to avoid a collision.