Classic barging

The two boats are on a collision course from position 1. The red (leeward) boat has rights, and the green (windward) boat should abort their approach.

Instead, the boats continue on their collision course until the red (leeward) boat is forced to bear away to avoid a collision.

The green (windward) boat should take a penalty (circles).

Next few scenarios . . .

Each of the next few scenarios starts out exactly the same, but end differently depending on what the leeward boat decides to do.

Lets them in

The green (windward) boat is fortunate to get a nice start at committee boat. No rule is broken.

Both boats have kept clear of each other - neither broke any rule.

This only worked out because the red (leeward) boat was nice enough (or inexperienced enough) to allow it.

Shuts the door

The red (leeward) boat heads up. To avoid fouling, the green (windward boat) must abort their approach.

Too late

This time, the red (leeward) boat waits too long to shut the door. By the time they head up, there is no way for the green (windward) boat to avoid both them and the committee boat.

The red (leeward) boat has broken Rule 16 (When a right-of-way boat changes course, she shall give the other boat room to keep clear) and should take a penalty (circles).

The green (windward) boat has broken no rule.