Collision Regulations and Right of Way
The core rules
Collision regulations exist so that two vessels approaching each other know who gives way. The most important rule is to keep a proper lookout and proceed at a safe speed so you can stop or manoeuvre in time. When two power-driven vessels meet head-on, both alter course to starboard and pass port-to-port. When crossing, the vessel with the other on its starboard side gives way. When one vessel is overtaking another, the overtaking vessel keeps clear. A vessel under sail generally has right of way over a power-driven vessel, and a vessel restricted in its ability to manoeuvre has priority over both.
PWC-specific traps
A PWC is a power-driven vessel, so it must give way in the same situations as a motorboat. Questions often suggest a PWC is more nimble and can therefore cut across. It cannot. Another trap is confusing the give-way vessel with the stand-on vessel: the stand-on vessel must still keep a lookout and act if a collision is imminent.
Worked rule of thumb
Picture the other vessel's starboard (right) side. If it is on your right, you give way. If it is on your left, you stand on but stay alert. Head-on means both turn right.
Safe navigation
Avoid sudden turns in front of other craft, keep clear of swimmers and anchored vessels, and never assume another operator has seen you.