The next changes in part 2 after the preamble start in rule 14.
Rules 10 trough 13 have NOT been changed in any way.
In rule 14 a new definition has been added:
14 AVOIDING CONTACT
A boat shall avoid contact with another boat if reasonably possible. However, a right-of-way boat or one entitled to room or mark-room
(a) need not act to avoid contact until it is clear that the other boat is not keeping clear or giving room or mark-room, and
(b) shall not be penalized under this rule unless there is contact that causes damage or injury.
Intent en purpose of rule 14 is not changed! Only a new "room" definition is added; the room at a mark.
Mark-room is defined as:
Mark-Room Room for a boat to sail to the mark, and then room to sail her proper course while at the mark. However, mark-room does not include room to tack unless the boat is overlapped to windward and on the inside of the boat required to give mark-room.
Room at the mark has not been changed by this. In the preamble of rule 18 in the current rule book this was already added to the definition of room. Now it has been structured by making it a defined word. The second sentence in this new definition gives a boat who is overlapped to windward and inside boat, the right to tack in rounding a leeward mark.
He has to to do it before he himself or the other boat has passed the mark. After that the outside boat is no longer required to give mark-room. A tacking boat would then be subject to rule 13.