1. room to sail to the mark when her proper course is to sail close to it, and
2. room to round the mark as necessary to sail the course.

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.

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 area 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 23 applies, avoid her.  A vessel underway, including a boat racing, is never a continuing obstruction.

See Clear Astern and Clear Ahead; Overlap

A party to a hearing is

1. for a protest hearing: a protestor, a protestee;
2. for a request for redress: a boat requesting redress or for which redress is requested, a race committee acting under rule 60.2(b), a technical committee acting under rule 60.4(b).
3. for a request for redress under rule 62.1(a); the body alleged to have made an improper action or omission;
4. a person against whom an allegation of a breach of rule 69 is made; a person presenting an allegation under rule 69.
5. a support person subject to a hearing under rule 60.3(d) or 69; any boat that person supports; a person appointed to present an allegation under rule 60.3(d).

However, a protest committee is never a party.

A postponed race is delayed before its scheduled start but may be started or abandoned later.

An allegation made under rule 61.2 by a boat, a race committee, a technical committee or a protest committee that a boat has broken a rule.

A boat is racing from her preparatory signal until she finishes and clears the finishing line and marks or retires, or until the race committee signals a general recall, postponement or abandonment.