Deirdre O’Regan



Susan McDonald is a Marine Traffic Controller with the Army Corps of Engineers, stationed along the Cape Cod Canal in Massachusetts. She works to ensure the safety of ships and boats as they transit the canal by monitoring their position and establishing directions and guidance as they pass each other.

It is not exactly your typical career, and when Susan was younger, not only could she not have predicted she would land this kind of job—she didn’t even know that this kind of job existed!

office adjacent to canal

working the rigging

Susan served in the Coast Guard, where she was trained on a variety of vessel types. One of her first duty stations was as crew aboard the USCG barque Eagle.

Susan’s career path hasn’t been a straight line, but it always involved working on or near the water. Her jobs and activities growing up ranged from lifeguarding and windsurfing to service in the US Coast Guard and later working on all kinds of boats. “My father informed me that I had to go to college after high school and figure out what I wanted to do with my life, but I had no idea.”

After a couple of semesters, she realized that college wasn’t for her. One summer when she was working as a bartender on Block Island—spending all her spare time windsurfing—she met some people stationed at the local Coast Guard base: “They showed me their boats and told me stories of rescues they made assisting boaters in distress…. Right then, I knew I wanted to join the Coast Guard, where I could be on the water and help people.”

Susan joined the Coast Guard and was trained in all aspects of vessel operations, boat maintenance, and safety at sea. During her military service, she worked her way up from seaman apprentice aboard the tall ship Eagle to qualifying as a coxswain of a 41-foot boat used for search-and-rescue and law enforcement. Other positions included working as a deck/training officer on a 110-foot Surface Effect Ship and serving on an aids-to-navigation team maintaining the buoys, lighthouses, and day markers that mariners rely on.


Growing up on the water, Susan loved windsurfing more than anything else, but there weren’t a lot of employers hiring people to do that, so she started to look around at what other kinds of jobs would keep her around the water.

She left the Coast Guard after eight years and passed her qualifying exams to become a licensed professional mariner. She got jobs on many different kinds of vessels: power and sailing yachts, a construction tender, ferries, a brigantine, and even a Chinese junk. When she heard that there were job openings with the Army Corps of Engineers (ACOE) at the Cape Cod Canal, she applied and got a job “operating a 41-foot utility boat on the canal, just like ones I used to run in the Coast Guard.” Later she became a marine traffic controller, and she has now been in the control room for five years.

“It took 6 months of supervised training to qualify and be able to stand my own watch. Controllers who are hired with no maritime experience usually qualify within a year. That’s right! Anyone who is willing to learn can train to be a marine traffic controller. No degree, license, or certificate needed.”

Susan’s “office” is right alongside the canal, giving her a front-row seat on all the shipping and boating that transits the waterway. It is hard to pin down what would be a typical day on the job because it varies by day and by season, and controllers have to monitor and deal with weather and mishaps with both mariners and their vessels, and people who use the canal access roads for cycling, walking, and fishing.

The average width of the Cape Cod Canal is only 480 feet. The currents can be very strong, and they reverse direction with the tide change. In addition to recreational boat traffic, very large ships transit the waterway, and the marine traffic controllers monitor the water depth and figure out the clearance beneath each vessel’s keel to prevent them from running aground. Above the water, there are three bridges that cross the canal; not all ships can fit underneath them. One of the bridges is a railroad bridge that gets lowered when trains come through. The controllers dispatch park rangers, patrol boats, and emergency personnel to respond to incidents, distress calls, alarms, or any other emergencies. There’s always a controller on duty—24 hours a day, 365 days a year. The crew rotate through shifts, and there are plenty of times when one has to work weekends or holidays.

Summer is busy, even hectic, as there are a lot more recreational boaters on the water in addition to the regular commercial ship traffic. Whales swing by on occasion, which requires the controller to radio all vessels in the area to keep their distance and slow their speed until the whales are safely out of the shipping lanes. Winters are more quiet, but the occasional snowstorm and ice floes in the canal can make things… interesting.

“On a typical shift, I will relieve the watch and immediately tuck into managing all these various activities. We are required to maintain vessel ‘active summary reports,’ which include checking in all vessels on the VHF radio, logging their last port of call, next port of call, draft, master’s last name, arrival time and date, departure time and date, transit direction, and the direction of the current at that moment…. The watches go by fast, and at the end of my shift it’s a nice feeling to know that I was of service to all who visited or transited the canal that day, be it vessels, pedestrians, animals, or rail traffic.

I have been a sailor and professional mariner for most of my life, but I do appreciate that in my role as a marine traffic controller, I get to go home at the end of my shift. Home is a place many mariners see little of, so I’m grateful for being able to go for a hike after work with my dog, Bowline, or have dinner with family and friends, not to mention a good night’s sleep.”

Did You Know?

Seal With Plastic Bottle

Marine animals consume plastic when they confuse it for food.

Small plastics and floating objects often look like food to aquatic animals and sea birds. When they eat plastic, it often gets stuck in their digestive system, making them feel full and unable to eat proper food.

What can YOU do?
Learn more at Getting Rid of Marine Debris