In the shadow of Louis Margot’s human-powered world tour, Christian Dumard is what is known in the industry as a router.

Raised on a boat for part of his childhood and later graduating in marketing, the Breton developed an interest in sailing, weather, and navigation. He became a navigator—the person responsible for trajectory and weather—on racing sailboats. Later, he transitioned to being a router (the land-based equivalent of a navigator) and has been practicing this profession for thirty years.

Christian Dumard, what is the purpose of routing for a rower?

It’s about planning routes, anticipating what might happen, and minimizing exposure to risks:

Beyond performance, the priority is to arrive safely without breaking everything. When embarking on a 120-day ocean crossing, you can’t predict what will happen beyond ten days. This is especially true for a rower because, if a large boat loses its mast, it will still float. But a rower can quickly be in danger.

Routing is also about optimization—finding the best compromise:

Since rowing boats are slow, it’s crucial to align with ocean currents, as they help maintain movement 24/7, even though rowing is only done for eight hours per day. However, the route shouldn’t be excessively lengthened just to catch the current.

What motivated you to join this adventure?

I love unique and unconventional projects—they are engaging. When routing a boat crossing the Atlantic, the journey lasts about 15 days, and once it arrives, the project is over. But Louis has been on his journey for nearly a year and a half! This creates bonds, and we feel more involved in the adventure. What’s great is that we also got to discuss the route together.

Speaking of the route, how did you choose it?

We conducted a climatological study of past years’ conditions along different routes to assess wind strength and sea state. Based on these factors, we chose a specific route. However, plans evolved—we initially considered the North Pacific route. Over time, we realized that if Louis arrived in Central America with strong winds, he might not be able to stop and could end up stranded on a beach with his boat looted. That wasn’t ideal. Colombia turned out to be a better choice—it was also a shorter rowing distance. […] There was still a risk of missing Colombia, but several ports were available along the way. Additionally, the wind was parallel to the coast, making it less dangerous.

How does Louis Margot receive your information?

Since he has Starlink [satellite internet provider] on board, a platform shows him the proposed route. When conditions change significantly—such as after departing from Portugal or between the Caribbean and Colombia—we send him a daily analysis and communicate via video.

During the Pacific crossing, updates are sent every two to three days since conditions are relatively stable and monotonous. When he’s about 15 days away from the Marquesas Islands, we’ll switch back to daily updates to help him target the islands and make key decisions: Should he stop in the Marquesas? Would another current make it better to continue further?

What dangers might he encounter at sea?

A solo boat always faces the risk of collision, regardless of the type of vessel. However, he has a beacon that continuously transmits his location, making him visible to other boats.
There are also risks of injuries or skin issues. The biggest concern, however, is the boat capsizing due to bad weather.

After departing across the Atlantic, Louis returned to Portugal. How was that decision made?

When he left, the conditions were borderline. We had set limits that we didn’t want to exceed—if I recall correctly, no more than 20 knots of wind [37 km/h], 3-meter waves, and a maximum number of days spent attached to a sea anchor.
Conditions deteriorated slightly, and we quickly saw that those limits had been reached. The decision to turn back was made quite naturally.