(pillow)Case of the Week (11) - 105

It’s Monday again and so here’s another Case for your pillow.

 CASE 105

Rule 10, On Opposite Tacks
Rule 14, Avoiding Contact
Rule 15, Acquiring Right of Way
Rule 16.1, Changing Course

When two boats are running on opposite tacks, the starboard tack boat may change course provided she gives the port-tack boat room to keep clear.

Assumed Facts
After sailing alongside P for some time on port tack, S gybes to starboard tack without breaking rule 15. Both boats continue to sail parallel courses. About two minutes after her gybe S begins to luff. P does not respond to the luff and the boats touch at position 3. There is no damage or injury.

Questions At the time of the contact, does rule 15 still apply? Does S break rule 16?

Answers S as the starboard-tack boat has right of way under rule 10, and P as the port-tack boat must keep clear. Rule 15 applies only briefly after S becomes the right-of-way boat, but rule 16.1 continues to limit how S may change course. S may luff provided that she does so in a way that gives P room to keep clear, and P must be prepared to react promptly, if necessary by gybing, to continue to keep clear. Rule 16.2 does not apply because, although the boats are on opposite tacks, P is not sailing to pass astern of S. Since P has room to keep clear of S by responding promptly when S luffs, S does not break rule 16.1. P does not keep clear and does not avoid contact with S. P therefore is to be penalized for breaking rules 10 and 14.


S also breaks rule 14 because, after it became clear that P was not keeping clear, S could have avoided the contact. However, because there was no damage or injury she is not to be penalized.
DSA 2005



Rule 15 and rule 16 are restrictions on the right of way boat, but they give limited ‘protection’ to the keep clear boat. First and foremost that boat must do everything reasonable possible to keep clear. Only after she is doing that and she still can’t keep clear, you can start thinking about that the ROW boat might be breaking 15 and/or 16.

Rule 14 is however a restriction that is ALWAYS in force. For the ROW boat the restriction might be a little less severe and she can not be punished if there’s no damage or injury, but she still has to follow that rule.