A sailboat and a PWC are meeting head-on. Which one is the stand-on vessel?
Sailboat. A PWC, or personal watercraft, is the give way vessel to any sailboat. In the US, a PWC refers to any small powerboat less than 13 feet in length. As such, it is a powerboat and must give way to all sailboats.
the PWC
A PWC is a Power Driven Vessel so she must give way.
When a sailboat overtakes a powerboat, the powerboat is the stand-on vessel. (Ref: SB-29)
Powerboat
Contrary to popular belief the power driven vessel is not always the give way vessel, a great deal depends on the circumstances.
When a sailboat overtakes a powerboat, the powerboat is the stand-on vessel. (Ref: SB-29)
When a sailboat overtakes a powerboat, the powerboat is the stand-on vessel. (Ref: SB-29)
Unless the sailboat is overtaking a power-driven vessel, the powerboat is the give-way vessel.
Rule 17Action by stand on vessel(a) (i) Where one of two vessels is to keep out of the way, the other (The stand on vessel) shall keep her course and speed.Please refer to the link provided below.
When it's the least maneuverable vessel in the encounter.
When there is a danger of collision, the "stand-on" vessel is the one that must maintain its course while the other must take avoiding action. Sailboats usually are the stand-on vessel when meeting a power-driven vessel, even if that vessel is another sailboat (if its engine is powering the boat, and regardless of whether its sails are raised or not). There are exceptions: if the power-driven vessel is "working," such as a fishing boat dragging nets, or the power-driven vessel is confined to a narrow channel due to its draft, then the sailboat must stay out of the way, by altering course if necessary. If a collision is imminent and the other vessel shows no signs of altering course, then the sailboat should take whatever course is necessary to avoid it.