Same tack, overlapped — is it the windward or the leeward boat that gives way?
The windward boat keeps clear. Under Rule 11, when two boats are on the same tack and overlapped, the boat closer to the wind must keep clear of the leeward boat — port and starboard never enters into it. Check the tack first: if it's the same, it's Rule 11, not Rule 10.
<iframe width="560" height="315" src="https://www.youtube.com/embed/b5FpZVkLQLw" 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/v/b5FpZVkLQLw/">Source: Sailing Kiwi</a></p>