Monday, 7 November 2011

(pillow)Case of the Week (43/11) - 38

(This is an instalment in a series of blogposts about the ISAF Casebook 2009-2012 with amendments for 2010. All cases are official interpretations by the ISAF committees on how the Racing Rules of Sailing should be used or interpreted. The cases are copied from the Casebook, only the comments are written by me.)

(pillow)Case picture


International Regulations for Preventing Collisions at Sea

The International Regulations for Preventing Collisions at Sea (IRPCAS) are intended to ensure the safety of vessels at sea by precluding situations that might lead to collisions. When the IRPCAS right-of-way rules replace the rules of Part 2, they effectively prohibit a right-of-way boat from changing course towards the boat obligated to keep clear when she is close to that boat.

Summary of the Facts
At about 0030, L and W were running on starboard tack on parallel courses about two hull lengths apart. W was to windward and clear astern of L and steadily closing up on her. The sailing instructions had, between sundown and sunrise, replaced the rules of Part 2 with the IRPCAS right-of-way rules.

L changed course to starboard, forcing W to respond in order to avoid a collision. W protested L on the grounds that ‘luffing was forbidden at night’. The protest committee upheld the protest under the IRPCAS, Part B, Section II, Rule 17. L appealed on the grounds that the protest committee had misapplied the relevant IRPCAS rules.

IRPCAS Rule 13(a) states that ‘any vessel overtaking any other shall keep out of the way of the vessel being overtaken’, and Rule 13(b) states, ‘A vessel shall be deemed to be overtaking when coming up with another vessel from a direction more than 22.5 degrees abaft her beam, that is, in such a position with reference to the vessel she is overtaking, that at night she would be able to see only the sternlight of that vessel but neither of her sidelights.’ In the above case W was the overtaking vessel. Rule 13(d) states, ‘Any subsequent alteration of the bearing between the two vessels shall not . . . relieve [the overtaking vessel] of the duty of keeping clear of the overtaken vessel until she is finally past and clear.’

The overtaken vessel, in this case L, has obligations towards the overtaking vessel. These are in Rule 17, which states in part, ‘Where one of two vessels is to keep out of the way, the other shall keep her course and speed.’ It is this rule that prohibits the racing manoeuvre known as ‘luffing’ while the boats are so close that L’s luff forces W to change course to avoid contact. Therefore, L’s appeal is dismissed and the protest committee’s decision to penalize her is upheld.

CYA 1976/32


The IRPCAS are not written for racing. Any situation involving two or more boats meeting, is to be solved by the safest way possible, to ensure no contact will occur.

It will feel ‘unnatural’ to most racing sailors, but that doesn’t mean they don’t have to follow the IRPCAS (or any other Government Right of Way rule) if that is stated in the Sailing Instructions. Then those rules become racing rules.

Do you know the IRPCAS good enough to give an interpretation sitting in a PC? I don’t. If any SI of an event I’m attending does have such a statement, I would have to bone up…..

Links to the International Regulations for Preventing Collisions At Sea (IRPCAS):

The Bosun’s Mate
Stormy Weather Software


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