SAN DIEGO, California — Seven minutes. That’s how quickly a smuggler operating a boat can get from Tijuana to the United States.

If people are the cargo, the trip is quick. For a boat, say, laden with 2,000 pounds of narcotics, maybe the journey takes 15 minutes. It is the mission of the Department of Homeland Security agency’s Air and Marine Operations to try to identify and grab them during what can be a frighteningly brief window before they make land.