Our next series of rules articles cover Part 2, Section C – At Marks and Obstructions. Section C covers Rules 18, 19, and 20. Rule 18 – Mark-Room is complex, so we’ll cover it in three separate articles, starting with Rule 18.1. Later, we’ll move on to Rules 19 and 20.

In 2018, the Inland Lake Yachting Association (ILYA) and SailZing, LLC partnered on a Fair Sailing initiative. As part of this initiative, SailZing worked with the ILYA and UK Sailmakers to develop a series of articles on the rules. With the rules changes in 2021, SailZing is updating these articles and adding video summaries.

Our thanks to UK Sailmakers for generating the animated scenarios.

Section C Preamble

The preamble to Section C prevents boats from using Rules 18-20 to gain an advantage at the starting line. It states:

“Section C rules do not apply at a starting mark surrounded by navigable water or at its anchor line from the time boats are approaching them to start until they have passed them.”

Rule 18.1 – When Rule 18 Applies

18.1 tells you when Rule 18 does or does not apply. We show the 2021 changes rules in red.

“Rule 18 applies between boats when they are required to leave a mark on the same side and at least one of them is in the zone. However, it does not apply

(a) between boats on opposite tacks on a beat to windward,

(b) between boats on opposite tacks when the proper course at the mark for one but not both of them is to tack,

(c) between a boat approaching a mark and one leaving it, or

(d) if the mark is a continuing obstruction, in which case rule 19 applies.

Rule 18 no longer applies between boats when mark-room has been given.”

Definitions

Here are the definitions related to Rule 18.1. We show changes to these definitions for 2021-2024 in red. The changes are not substantive.

Mark  An object the sailing instructions require a boat to leave on a specified side, a race committee vessel surrounded by navigable water from which the starting or finishing line extends, and an object intentionally attached to the object or vessel. However, an anchor line is not part of the mark.

Zone 

The area around a mark within a distance of three hull lengths of the boat nearer to it. A boat is in the zone when any part of her hull is in the zone.

Note: some classes may change the length of the zone and note this in the NoR or SIs.

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.

Previously-defined terms (click to refresh your memory): tack, proper course

Rule 18.1 Changes

The 2021 changes modified Rules 18.1 and 18.2 slightly. Rule 18.1 now includes a statement that Rule 18 turns off when mark-room has been given. This applies to the entire rule. The corresponding statement in Rule 18.2 was removed. See the markup to the right. See our post on 2021-2024 changes for the reasoning behind the change.

Rule 18.1 Scenarios: Does Rule 18 Apply?

Example 1

Yellow and Blue are sailing upwind within the zone near the windward mark.

Does Rule 18 apply to Yellow and Blue?  Answer

Example 2

Yellow and Blue are sailing upwind within the zone near the windward mark.

Does Rule 18 apply to Yellow and Blue?  Answer

Example 3

Yellow and Blue are sailing near the windward mark. Blue is in the zone and does not need to tack to reach the mark.

Does Rule 18 apply to Yellow and Blue?  Answer

Example 4

Yellow and Blue are finishing upwind. Blue does not need to tack to finish.  

Does Rule 18 apply to Yellow and Blue?  Answer

Example 5

Yellow and Blue are sailing downwind to the leeward gate on opposite tacks. Blue is in the zone. 

Does Rule 18 apply to Yellow and Blue?  Answer

Example 6

Yellow and Blue are sailing toward an island. The course requires sailing around the island.  

Does Rule 18 apply to Yellow and Blue?  Answer

Example 7

Yellow and Blue are sailing downwind with spinnakers to the leeward gate on opposite tacks. Yellow is in the zone. Blue is currently well outside the zone.  

Does Rule 18 apply to Yellow and Blue?  Answer

Example 8

Yellow and Blue are finishing downwind on opposite tacks.

Does Rule 18 apply to Yellow and Blue? Answer

Rule 18.1 Turn-off Examples

The new sentence in 18.1 states that Rule 18 turns off when mark-room has been given. We’ll show examples as we cover the remaining parts of Rule 18.

SailZing – Racing Rules Category
World Sailing Racing Rules of Sailing 2021-2024