Racing Rules: "Overlap"

How to Determine Overlap

In order to determine whether or not boats are overlapped, you must look at their hulls, and their equipment in normal position. A few examples of

equipment in normal position

are

• rudders in their down and locked position,
• a retractable bowsprit when extended sailing downwind, or
• a spinnaker flying.

Some examples of equipment not in normal position are:

• a retractable bowsprit extended while sailing upwind,
• a spinnaker with sheets or halyards loosed, or streaming out while hoisting or dousing (or shrimping),
• a line trailing in the water behind a boat.

Equipment in normal position counts; equipment out of normal position does not.

Draw an imaginary line through the centerline of each boat. Draw another imaginary line perpendicular to the first at the aftmost point of the hull or equipment in normal position. If one boat (her hull and equipment in normal position) is entirely behind that second line, then she is

clear astern

and the other is

clear ahead

. If neither boat is clear astern of the other, then the two are

overlapped

.

Overlap on the Same Tack

Here is a diagram showing two pairs of boats on the same tack on a beat to windward. For each pair, I've drawn imaginary centerlines and perpendicular lines on the lead boat. Note that I've drawn the aftmost point slightly behind the hull because that's where the rudders are. The yellow boat is completely behind that line, so Blue is

clear ahead

and Yellow is

clear astern

. For the other pair, the trailing boat is not completely behind that line, so the boats are

overlapped

, and I've colored them both green.

I've drawn an equivalent diagram showing boats sailing a beam reach on the same tack. As above, Yellow is completely behind the aftmost point of Blue so Yellow is clear astern and Blue is clear ahead. The two green boats are overlapped.

And, finally, here's a picture showing same-tack boats on a run. I've drawn the boats as monohulls this time, because the program I used made it easier to show spinnakers that way. The interpretation is the same though. Blue is clear ahead and Yellow clear astern. Even though their hulls are not overlapped, their equipment in normal position is, so the two green boats are overlapped.

to be continued...

Overlap on Opposite Tacks

Boats on opposite tacks may also be overlapped. Here are a few such circumstances. In the first, I've shown two boats on opposite tacks sailing a broad reach. The terms apply because both boats are sailing more than 90 degrees from the true wind (even if their apparent wind is directly abeam). I've drawn centerlines and perpendicular lines on both boats. Because neither boat is clear astern of the other, the two are overlapped.

Here is an example of boats sailing directly downwind on opposite tacks. As previously, I've drawn monohulls to show the spinnakers. Also, the fact that the port-tack boats are slightly angled is an artifact of the drawing program. Please ignore that imperfection. Once more, the Blue boat is clear ahead and Yellow clear astern. The green boats are overlapped.

Once more, here are two boats approaching a leeward mark. One is sailing (nearly) dead downwind on port tack, the other is on a starboard tack broad reach. Neither is clear astern of the other, so they are overlapped. This important relationship is often overlooked and misunderstood by boats sailing the rhumb-line.

to be continued...

Overlap Between Multiple Boats

There is one more part to the definition of overlap. That is, two boats also overlap when a boat between them overlaps both. Even if their hulls and equipment do not overlap, two boats are overlapped when they are both overlapped by an intervening boat. Here is an example. In this diagram, the two green boats are not directly overlapped, but the orange middle boat does overlap both. Therefore, the green boats are overlapped.

Important Note! The boat that overlaps both must be in between them. Some people like to call that boat the

meat in the sandwich

. In order for overlap to exist, the meat must be between the pieces of bread. If there's no meat in the sandwich, then there's no overlap. I've illustrated that below. Although the Orange boat is overlapped with both Blue and Yellow, she is not between them. Therefore Blue and Yellow are not overlapped with each other.

I hope that helps,
Eric Rasmussen
US SAILING Certified Judge
Chair, SAYRA Appeals Committee

Thanks!
you rock

Very helpful, thanks!!

Keep them coming.

Rudder down and locked is arguable. In some classes, it is completely normal to sail downwind with a rudder up and locked. Upwind too, in light conditions (although I've heard of some young guns doing this internationally in all conditions).

Raising a rudder simply to create an overlap would be tough to defend.

Mike

Rudder down and locked would certainly be

in normal position

. Rudder up may or may not be. Sometimes, raising the rudder would be normal. For example, a Hobie 16 going downwind in light air with one rudder up would be normal position. A rudder kicked up after hitting bottom would not.

I find it difficult to envision a circumstance where the boat ahead would raise a rudder in order to establish overlap.

Or be able to be THAT precise with when overlap is or isn't present.

Didn't Russell Coutts do that a couple of ACs ago on the last run to force Team New Zealand to allow him to gybe at the layline instead of push them off into oblivion?

Thanks Eric, I agree with that post, just wanted to clarify from your prior one.

Jake, raising a rudder can add a foot or so of length, people will notice that.

Mike

Great stuff. Keep it up.

What was the thread topic name (so I can search for it) which you went over establishing overlap on a boat pre-start (or during the sequence).. Like a

J hook

to peel someone off at the boat end.?

Do you mean the barging thread?

I just noticed that I included the wrong diagram for boats on the same tack on a run. I'm surprised that nobody called me on that.

Anyway, here it is: