How do I call and record an interference?

Under the SSA Rulebook 2025 (Sections 3 and 4):

• Judges rule on interference. A penalty is applied only if a majority of the panel marks it on their sheets. The Head Judge may call it only if no majority is reached, and judges who didn't see the incident can't vote on it.
• Keep scoring the ride. The interfering surfer's ride is still scored, but if the majority calls interference it becomes zero.
• Riding interference: draw a triangle around the interfering score with an arrow to the score of the surfer who was interfered with.
• Paddling interference: draw a triangle on the line between waves where it happened (or above the score if the wave was ridden), with an arrow to the interfered surfer's score or line.
• Don't discuss scores or interference calls with other judges; the Head Judge keeps judges visually separated.
• Once made, an interference decision can only be changed by the Head Judge if it relied on inaccurate video or audio technology. Judges won't discuss calls with surfers.
• Interference is announced only after the Head Judge or Contest Director approves it.

Penalties: non-priority situations, Penalty 1 (second-best ride halved); priority situations, Penalty 2 (second-best ride zero); at SSA events, blocking a potential scoring ride in the last five minutes, Penalty 3 (best ride zero), or disqualification if judged intentional.