Originally Posted by bobcat
Here RED allowed Green to get to position 2. Not necessarily overlapped with R/C in our defined sense of overlap but Green doesn't have a legal out.
[Linked Image]

This diagram doesn't illustrate barging. It shows a case where the signal boat is not a mark (the mark is the buoy to the left). Here, the boat is an obstruction and inside boats are entitled to room. Note that this is a very unusual exception -- I have never seen a starting line set this way.

I hope that helps,
Eric