We collided at a mark with damage — how can BOTH boats be disqualified?

Rule 14 requires every boat — including the right-of-way boat — to avoid contact if reasonably possible. The keep-clear boat kept no lookout and broke Rule 10 and Rule 14. But the right-of-way boat could have luffed to avoid a collision that caused damage, and didn't — so she's penalised under Rule 14 too. Right of way is not a right to collide. (World Sailing Case 26.)

<iframe width="560" height="315" src="https://www.youtube.com/embed/srIpEm5mIXA" title="Sailing Kiwi" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
<p><a href="https://sailing.kiwi.nz/windward-mark/case-26-both-boats-disqualified/">Source: Sailing Kiwi</a></p>