The mission of the dredging service is to maintain the navigational depths in the shipping channel and the quayside trenches. Different dredgers and service craft operate on the Loire Estuary.

The Samuel de Champlain is a mobile suction dredger used to dredge the channel. She has a well capacity of 8 500 m3. She operates 24 hours a day with two 16-man watches.

The fleet also comprises two service craft:
- the tugboat the Milouin, which levels the channel following the passage of the Samuel de Champlain;
- the stationary suction and break-up dredger André Gendre, which is used to dredge the trenches.

The dredging Service employs over 120 people, whether seagoing or onshore personnel.