In the last article, I discussed the changes to rule 18, mark-room. This time, I am going to discuss the change in the definition of mark-room, obstruction, continuing obstruction and a change in rule 19, obstructions.
The 2021-2024 rules, in the definition of mark-room, listed two stages, room to sail to the mark and room to pass the mark.  There was no obvious end.  Rule 18.1(b) says “Rule 18 no longer applies between boats when mark-room has been given”.  It had been given when the mark had been passed since that was the end of the definition of mark-room, but that was not very clear.  A third part (c) has been added to the definition of mark-room, in the 2025-2028 rules, which says, “to leave it astern”.  Once the boat entitled to mark-room has left the mark-astern, she has been given mark-room and rule 18 ends.
The 2021-2024 rules included room to pass the mark “without touching the mark”.  That was redundant since the definition of room says, “including space to comply with her obligations under the rules of Part 2 and rule 31.”  Rule 31 is the rule that tells boats not to touch marks.  This redundant phrase has been deleted.
Finally, the 2021-2024 definition of mark-room ended in a paragraph about room including room to tack under specific circumstances.  That was confusing since as soon as the boat entitled to mark-room passed head to wind, rule 18 turned off.  This has also been eliminated.
There is a new definition for a continuing obstruction in the 2025-2028 rules. Rule 19.2(c), previously referred to a continuing obstruction, but it was never defined.  There was a sentence at the end of the definition of obstruction that listed some things that were not continuing obstructions.  These are all now in the new definition, which also specifies how long you have to be able pass alongside an obstruction, for it to be continuing obstruction.
Other than removing the restriction on continuing obstructions, there is very little change in the definition of obstruction itself.  One change is that it previous said that an area designated in the sailing instructions could be an obstruction.  Now it can be designated in any rule.  The sailing instructions are rules so they can still designate an obstruction, but the notice of race can as well.


In the diagram we see Yellow and Blue approaching an obstruction. This could be an anchored spectator boat.  It could also be the Signal Vessel, as long as they are not approaching it to start.  Blue is leeward so she has right of way.  According to Rule 19.2(a) Blue can choose which side of the obstruction she wishes to go.  If she goes to leeward, then she has to give Yellow room to pass in between Blue and the obstruction.  If she goes to windward, Yellow has to give Blue room to pass in between Yellow and the obstruction.  Blue waits until the last minute to make the decision.  Between position 3 and 4 Blue heads up very quickly.  Yellow attempts to respond but is unable to.  Blue breaks the new last sentence of rule 19.2(a).  She has not given Yellow room to keep clear.  If there were no obstruction here, Blue would have broken rule 16. It turns out that rule 16, is a rule that Blue is exonerated for breaking, when she is sailing within the room she is entitled.  This change to the rule puts this reasonable restriction back into the situation and protects Yellow from a rapid last minute course change. 


Anchored boats are not the only types of obstructions. A right-of-way boat, that boat boats have to keep clear of, can be an obstruction.  In the second diagram Purple and White are overtaking Grey.  They are clear astern at position 1 so both have to keep clear of Grey and Grey is an obstruction to them.  Yellow and Red are on port tack approaching Green on starboard tack.  Green is obstruction to Yellow and Red.  Yellow and White have a choice about which side of the obstruction to pass but when they choose they have give Red and Purple room.
 

RRS 2025-2028  (text underlined is new)
Mark‑Room   Room for a boat
(a)        to sail to the mark when her proper course is to sail close to it,
(b)       to round or pass the mark on the required side, and
(c)        to leave it astern.
Obstruction   An obstruction is
(a)        an object that a boat could not pass without changing course substantially, if she were sailing directly towards it and one of her hull lengths from it;
(b)       an object that can be safely passed on only one side; or
(c)        an object, area or line that is so designated in a rule.
However, a boat racing is not an obstruction to other boats unless they are required to keep clear of her or, if rule 22 applies, avoid her.
Continuing Obstruction   An obstruction is a continuing obstruction when the boat with the shortest hull referred to in the rule using the term will pass alongside it for at least three of her hull lengths. However, the following are not a continuing obstruction: a vessel under way, a boat racing, or a race committee vessel that is also a mark.
Room   The space a boat needs in the existing conditions, including space to comply with her obligations under the rules of Part 2 and rule 31, while manoeuvring promptly in a seamanlike way.
19.2     Giving Room at an Obstruction
(a)        A right‑of‑way boat may choose to pass an obstruction on her port or starboard side. If a right‑of‑way boat changes course when choosing on which side to pass the obstruction, she shall give the other boat room to keep clear.
(b)       When the boats are overlapped, the outside boat shall give the inside boat room between her and the obstruction, unless she has been unable to do so from the time the overlap began.
(c)        While boats are passing a 9+- obstruction, if a boat that was clear astern and required to keep clear becomes overlapped between the other boat and the obstruction and, at the moment the overlap begins, there is not room for her to pass between them,
(1)       she is not entitled to room under rule 19.2(b), and
(2)       while the boats remain overlapped, she shall keep clear and rules 10 and 11 do not apply.
RRS 2021-2024 (text struckthrough has been deleted)
Mark-Room   Room for a boat to leave a mark on the required side. Also,
(a)        room to sail to the mark when her proper course is to sail close to it, and
(b)       room to round or pass the mark as necessary to sail the course without touching the mark.
However, mark‑room for a boat does not include room to tack unless she is overlapped inside and to windward of the boat required to give mark‑room and she would be fetching the mark after her tack.
Obstruction   An object that a boat could not pass without changing course substantially, if she were sailing directly towards it and one of her hull lengths from it. An object that can be safely passed on only one side and an object, area or line so designated by the sailing instructions are also obstructions. However, a boat racing is not an obstruction to other boats unless they are required to keep clear of her or, if rule 22 applies, avoid her. A vessel under way, including a boat racing, is never a continuing obstruction.
Room   The space a boat needs in the existing conditions, including space to comply with her obligations under the rules of Part 2 and rule 31, while manoeuvring promptly in a seamanlike way.
19.2     Giving Room at an Obstruction
(a)        A right‑of‑way boat may choose to pass an obstruction on either side.
(b)       When boats are overlapped, the outside boat shall give the inside boat room between her and the obstruction, unless she has been unable to do so from the time the overlap began.
(c)        While boats are passing a continuing obstruction, if a boat that was clear astern and required to keep clear becomes overlapped between the other boat and the obstruction and, at the moment the overlap begins, there is not room for her to pass between them,
(1)       she is not entitled to room under rule 19.2(b), and
(2)       while the boats remain overlapped, she shall keep clear and rules 10 and 11 do not apply.