When two personal watercraft are crossing at right angles what should the craft on the right do?

The craft on the right is the "stand on" vessel, the one with the right of way, he must remain on course at speed and be prepared to avoid collision if the "make way vessel" (to port side) makes no effort to avoid or change course or speed.

Avoid collisions if you are able, do not assume the operator of the other vessel sees you or knows the "aids to navigation."

Exceptions to these rules, powered vessels must give way to sail and oared vessels, and less maneuverable or towed vessels, regardless of orientation.