The pecking order - right of way priority.

Rule 18 of the Navigation Rules gives the right of way priority (pecking order) between vessels, when not in conflict with special rules for channels, traffic lanes, or when overtaking. Rule 3 defines the types of vessels. It’s essential to memorize the order. The highest priority  goes to an overtaken vessel (all overtaking vessels stay out of the way). In descending order, the others are: Not Under Command, Restricted in Ability to Maneuver, Constrained by Draft, fishing vessel, sailing vessel, power-driven vessel, seaplane (lowest priority). Rule 3 defines the vessels. There is a memory aid in the right of way priority entry, p. 335 in the Mariner’s Guide. The text of the rules is available at www.navcen.uscg.gov/?pageName=navRulesContent.