With a dive entry on an acoustic signal, the first competitor races 50 m freestyle passing under two obstacles. After the first competitor touches the turn wall the second, third, and fourth competitors repeat the procedure in turn.
Competitors must surface after the dive entry before the first obstacle and after passing under each obstacle. “Surfacing” means the competitor’s head breaks the plane of the surface of the water.
Competitors may push off the pool bottom when surfacing from under the obstacles.
Swimming into or otherwise bumping an obstacle is not a behaviour that results in disqualification.
The first, second and third competitors must leave the water upon finishing their legs of the relay without obstructing any other competitors. The first, second and third competitors may not reenter the water.
Obstacles: Obstacles are fixed at right angles on lane ropes in a straight line across all lanes. The first obstacle is positioned 12.5m from the starting edge with the second obstacle 12.5m from the opposite end. The distance between the two obstacles is 25m.
In addition to the ILS Competition Manual General Rules and Procedures in Section 3.0 and those outlined in Section 4.1-4.3 and Section 10 the following behaviour will result in disqualification:
Passing over an obstacle and not immediately returning over or under that obstacle and then passing under it.
Failure to surface after each dive entry.
Failure to surface after each obstacle.
Leaving the start before the previous competitor has touched the wall) Failure to touch the finish wall.
A competitor re-entering the water after completing his or her leg of the relay.
One competitor repeating two or more legs of the event.