Edgartown Police Officers Michael Snowden, left, and William Bishop train their sights on a suspect. — Stacey Rupolo

A woman is being held against her will by an intoxicated boater. A scalloper fishing out of season refuses to let police onboard, then leads them on a high-speed chase.

These are two of the scenarios that police officers from Oak Bluffs, Edgartown, Quincy Marine Unit (QMU), Boston Marine Unit (BMU), State Police Marine Unit (SPMU), and Massachusetts Environmental Police (MEP) faced at a Maritime Tactical Training session hosted by Oak Bluffs Police last Thursday.

Mark Brennan from Hingham-based Maritime Tactical Training, and officers from BMU, MEP, and QMU came to the Island to take part in a one-day seminar on maritime felony-arrest tactics.

https://youtu.be/46rW7O5mT0c

“There’s no such thing as a low-risk stop on the water,” Mr. Brennan told the 25 officers mustered at the Oak Bluffs Police Department conference debriefing room. “Probably 90 percent of boats have a knife on them. A lot of them have guns.”

Underscoring the point, Massachusetts Environmental Police Lieutenant Robert Akin told the room about a boat that was on a seagull-shooting safari, with 40 guns aboard.

Mr. Brennan talked about the myriad variables that come into play in a stop on the water — ocean current, wind, obstructions like pilings and bridges, other boats, and mercurial maritime weather.

“You can also make weather work for you and use the sun to make your approach,” he said.

Mr. Brennan stressed the importance of communication, among law enforcement agencies and between law enforcement and suspects. In a multi-agency response, all radios need to be on the same frequency, which presented problems on Thursday — some officers had encrypted radios, some did not.

“That’s why we do training like this,” Mr. Brennan said. “Communication is everything.”

Nonverbal communication is also critical among crewman on a boat going 30 knots with twin 250-horsepower engines roaring.

Two State Police boats along with Oak Bluffs and Edgartown police boats were supposed to drill in the open water, but 25 mph gusts out of the north moved the exercise into Lagoon Pond.

Boats rotated in different roles — the fleeing criminal, the lead boat, and the backups. Protocol calls for the lead boat to get a “sneak peek,” visual contact with the boat’s crew and a visual scan of the deck, which means running just five feet away at 35 miles an hour.

What looked like mayhem, with pursuing boats crisscrossing and following in staggered formation, was actually the execution of a very specific game plan.

The Edgartown boat, the only boat with twin 300-horsepower engines, was clearly the fastest of the lot. Edgartown was also the only crew Mr. Brennan has trained with that included a paramedic.

Mr. Brennan said once the fleeing boat stops, initial communication requires “command presence” — weapons drawn with one officer giving instructions in a tone that leaves no doubt as to the seriousness of the situation. Two of the crew drew pistols, and a third drew a rifle. Police used blue and orange fake guns during the exercise.

Patting down a suspect for weapons on a boat isn’t as straightforward as it is during a traffic stop. Mr. Brennan went over how to bridge the crucial time between the suspect stopping, and getting him or her in handcuffs. You can’t pat them down from 10 feet away.

Except for angering a man whose small dingy was tossed in the flotilla’s robust wake, Mr. Brennan said the training was a success, with a caveat.

“You have tools in your toolbox that you didn’t have this morning. This will help make this region stronger.” he said. “Keep in mind, these are perishable skills. Unless you have a dedicated marine unit, you need to practice this until it becomes second nature.”