It's not a matter of being "essential" for any number of boats - after all, a gate was used in the last America's Cup when there were only 2 boats.

It's a matter of adding another level of strategy to the game. Do you go left or right? Which mark is favored? In traffic, which mark am I more likely to come out cleaner? There are a lot more opportunities to pass with gates. They add a lot to the game.

A single leeward mark entrenches the pecking order as boats are forced into single file as they round the mark. Boats tacking to starboard after rounding create collision hazards.

Gates were introduced to the Hobie class 15 years ago by PU at the H-17 North Americans in Syracuse. We've been using them ever since. Once you've become accustomed to them, you never want to go back to a single leeward mark again.