Explainer

Stop That Ship!

How do you make an arrest at sea?

A five-day boat chase through the North Atlantic ended Wednesday when a Russian trawler accused of illegal fishing escaped the pursuit of the Norwegian coast guard. Patrol boats tried to escort the rogue ship to port, but it turned around and made a beeline for Russian waters. At one point, its captain even threatened to ram the Norwegians to avoid arrest. How do you make an arrest at sea?

Board the ship and put everyone in handcuffs. U.S. Coast Guard cutters first try to pull over a mischievous ship by making radio contact with its crew. (P.A. systems can be used if no one responds to the radio call.) They ask how many people and weapons are on board and tell them to assemble in one area—the crew’s mess, for example. Boarding teams deploy either from small boats or helicopters; they search the ship and take any lawbreakers they find into custody. If they have to bring prisoners back to the cutter, the team will leave several members behind to pilot the criminal vessel to a nearby port, where U.S. Marshals may seize the boat as evidence. In some cases, the Coast Guard may leave a crew in control of its ship and escort them to a nearby port.

Some nautical outlaws—like the Russian trawler—try to flee the scene of a crime. Patrol boats may fire warning shots across their bow (i.e., into the water in front of them). They may also attempt to disable the ship’s engines. For smaller vessels, this may be as easy as firing a copper slug into an outboard engine. Police can drown the engine of a bigger ship by firing a water cannon into its exhaust stacks. (Sometimes helicopters spray water down the stacks with fire hoses.)

Another approach is to immobilize the ship by “fouling its propeller.” Patrol boats and helicopters sometimes entangle fugitive vessels by firing a netlike device into the water in front of it. (The USCG is now lobbying to install free-floating “running gear entanglement systems” to protect ports from terrorist attacks.) In the future, maritime law enforcement may send out remote-controlled “RoboSkis” armed with these net launchers.

Bonus Explainer: How do local cops on patrol boats make arrests? They turn on their lights and sirens and pull over the offender. If they have to take someone into custody—for driving a boat while intoxicated, for example—they’ll turn over control to another passenger. (If no one else on board can drive, the officer will tug the boat to a pier or radio a local towing company.) In the rare event when someone tries to escape, police boats will pursue as far as possible. Since bullets can ricochet off the water’s surface and pose a risk to nearby civilians, water patrol officers almost never fire warning shots.

Bonus Bonus Explainer: It’s also possible to arrest a boat, as opposed to its crew. According to maritime law, a boat can be held responsible for unpaid bills or wages or any damages it causes in accidents. If someone makes a claim against a boat, local authorities can “arrest” it and force its owner to pay up.

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Explainer thanks Sgt. Ralph Bledsoe of the Missouri State Water Patrol and Lt. Cmdr. Jeff Carter of the United States Coast Guard.