On a crowded, busy waterway, it can sometimes be difficult to tell who has the right of way. Unfortunately, many boating accidents result when drivers do not understand the ways in which boats are supposed to interact. Operating a boat is just like driving a car: if you do not understand the rules governing right of way, you are putting everyone around you in danger.
The most basic rule governing right of way on the water is that a boat must yield to any boat that is in the angle extending from the front of the boat forward and from the rear starboard (right) corner of the boat perpendicular to the boat. This area is known as the "danger zone," and boats are obliged to yield or "give way" to any other vessels in their danger zone. Conversely, if you are in another boat's danger zone, that boat is required to yield or "give way" to you. This basic rule of boating is most applicable when two boats are traveling towards the same spot; the yielding boat is obliged to slow down or "give way" and pass behind the boat on its starboard side.
At night, boats will display colored lights in order to maintain the proper right of way. The starboard side of the boat will have green lights, signaling to other boats that they have the "green light" to go ahead, while the port side of the boat will have red lights, indicating that boats on this side should yield or "give way".
The right of way on the water may also be determined by the types of boats involved. For instance, a powerboat (i.e., a boat with a motor) should always yield to a sailboat under sail.
Powerboats must also yield to any boats that are being towed or propelled with oars. These restrictions on powerboats are meant to keep smaller boats from being rocked violently by a large wake.
When two sailboats meet, a boat on a port tack is required to yield to a boat on a starboard tack. In situations where both boats are on the same tack, the boat closest to the origin of the wind should yield. As a sailor, one should always abide by these rules while remaining aware that not every sailor knows them. In other words, one should follow the rules and be vigilant to ensure that others are doing so as well.
Keep in mind the General Prudential rule: "When from any cause, the vessel required to keep her course and speed finds herself so close that collision cannot be avoided by the action of the give-way vessel alone, she shall take such action as will best aid to avoid collision".