At sea, the priority rules are governed by the RIPAM (International Regulations to Prevent Collisions at Sea). This Regulation grants rights and obligations to which everyone is obliged to comply. In the event of a risk of collision, the rules establish which of the two vessels must manoeuvre to avoid collision.
It should also be remembered that the priority ship must do everything possible to prevent the collision if the other ship does not do so. In all circumstances, let's show some marine sense and courtesy, the priority boat can quite easily choose to change its route if the manoeuvre is easier for it.
The collision course
A risk of collision between 2 boats is also called a collision course. This risk is assessed using a bearing compass. The collision course is confirmed if the compass bearing of the approaching vessel does not change significantly.
Constant increases
The 4 fundamental priority rules
The following 4 rules are a kind of canvas to quickly determine the distribution of priorities. As soon as the priority is established, the process of the canvas ends.
Remember that you must have the RIPAM on board. It is a complete set of rules that you should study and know to navigate safely.
1 - A sailboat has priority on a motorboat
RIPAM gives priority to sailboats over motorboats, whether they are the size of an annex or a tanker.
Be careful, this priority is lost when faced with a motor vessel with limited manoeuvring capacity (such as a tug in action for example). Or in a traffic separation zone (TSA). Or if it is a fishing boat in fishing action.
Use marine sense and consider this priority with caution. Do not underestimate the manoeuvring time of a motor vessel, a tanker launched at 20 knots takes several minutes to adjust its course. Also, assume that on the bridge or radar, no one has seen you.
2 - A ship overtaking another must avoid the collision by moving away from it
Rule 13 applies. Whether it is a sailboat or a motorboat sailing faster than any other, it is always the fastest that must ensure the avoidance manoeuvre.
If you are the overtaking ship, be sure to move far enough away so as not to disturb the slowest. Especially if it is a small sailboat sailing at 5 knots, overtaken by a motorboat launched at 20 knots. Manners at sea.
3 - A starboard tack sailboat has priority over a port tack sailboat
This is the famous RIPAM Rule 12. When two sailboats follow a collision course, the right reflex is to determine the amures at which each of the boats sails.
In other words, define on which sides the sailboats receive the wind.
Sailing on starboard tack - the wind coming from tribord? - the sailboat has priority. Receiving the wind from the port side, the port tacked vessel had to manoeuvre to avoid collision.
The sailboat sailing on port tack will therefore spend its time checking that it is not on the way to collide with another sailboat.
This rule makes sailors say that a starboard tack sailboat is the king of the seas. This does not preclude regular checks downwind to ensure that no boats are on the way to collision.
4 - Even tack, the leeward sailboat has priority
Rule 12 is still the reference. Remember this rule well, as it is often useful (especially with motor boats).
When two sailboats sail on the same tack, port or starboard, it is the leeward sailboat - the one that makes the closest course to the wind - that has priority. The other sailboat will have to move away while luffing, or pass behind or turn around.
Attention, the spinnaker does not grant a right
A sailboat under spinnaker is not considered to be in restricted manoeuvring capability by RIPAM. He will therefore have to comply with the rules and possibly lower the spinnaker to avoid a collision. Once again, let us show courtesy and common sense by giving priority, if possible, to the brave crews sailing under spinnaker.
