The crew of the survey vessel Catlett are no strangers to navigating the channels around the Port of Baltimore. Outside the boat’s tinted windows is a constant reminder of why their most recent survey trips are different than normal. Pieces of the Francis Scott Key Bridge jut into the air alongside cranes and shipping containers around the bow of the Dali.

As a part of the U.S. Army Corps of Engineers, the crew’s job is to slowly navigate back and forth in the water — like a lawn mower — so their instruments can create a hydrographic map of what’s under the surface. A hydrographic map,more commonly known as a marine map, shows the contours of the bottom of the coastline, the depth of the water, and the tides and currents in a given area.

The crew’s current mission is to look for debris from the Key Bridge collapse. They are one part of the complex operation playing out in the Patapsco River to reopen the port.

Jacob Tuer, assistant operator for the Catlett and the day’s captain, steers as the Dali and fallen Key Bridge are seen out the window on Tuesday, April 16, 2024.

Binoculars and sunglasses sit near the control panel of the Catlett.

The Baltimore skyline is seen behind wreckage from the Key Bridge collapse.

A crew passes by the Dali.

A dredge bucket picks up debris from the Patapsco River and deposits it onto a barge.

Brian Retz, hydrographic survey technician on the Catlett, pulls a CastAway instrument from the water after dropping it to the bottom of the channel. The process is done at the top of every hour.

Workers cut through steel from the Key Bridge wreckage.

Crews pull up the biggest piece of the Key Bridge yet from the Patapsco River with cranes.

A machine moves a piece of the Key Bridge.

Jeff Peacock, chief of the Key Bridge debris mission, speaks on the radio while steering the Catlett. Peacock and Tuer took turns steering the boat throughout the day.

Jacob Tuer looks back to speak with a crewmate.

The Dali and collapsed Key Bridge are seen reflected in the windows of the Catlett.

Jeff Peacock, left, secures the Catlett as Jacob Tuer makes sure the boat is pulled up evenly to the pier at the conclusion of their day.