Can a boat giving mark-room prevent a boat owed mark-room from tacking? [Sailing Rules 2021-2024]

In World Sailing case 15, a boat owed mark-room is forced outside the zone by the boat giving mark-room. Rule 18 (mark-room) is put up against Rule 13 (while tacking). Which boat is penalized? Note: this video was recorded against the 2021-2024 rules, and the title says so on purpose. Case 15 still stands under 2025-2028 and the answer is unchanged: B may hold course and thereby prevent A from tacking. Rule 18 was renumbered since, and two of the numbers in this video swap places, so read these carefully. Rule 18.2(b) in this video is rule 18.2(a)(2) in the current rulebook. Rule 18.2(d) in this video is what the current rulebook calls rule 18.2(b). So today's 18.2(b) is not the 18.2(b) discussed here, it is the provision this video calls 18.2(d). Rule 18.1(a) in this video is rule 18.1(a)(1) today. One point also lost its source. The video explains that the mark-room A is entitled to does not include room to tack, citing the last sentence of the definition of mark-room. That sentence has been removed, and the definition no longer mentions tacking at all. The conclusion still holds and the case still reaches it, but through the definition's silence rather than an explicit exclusion. Subscribe for more videos on the racing rules of sailing:    / @racingrulesgeek   Sources: The Racing Rules of Sailing for 2025-2028 https://www.sailing.org/inside-world-... World Sailing Case Book for 2025-2028: https://www.sailing.org/document/worl... Chapters: 0:00 / What was the situation in case 15? 0:40 / How were the racing rules applied? 2:16 / What could the boats have done instead? #sailingrules #racingrules #sailingrightofway This video was made with Clipchamp.