From the late 19th century onwards, the DEME founders invest heavily in expanding and modernizing their fleet, while also being active in shipbuilding. Vessels are commissioned and built at Dutch and Belgian shipyards, including Smit in Kinderdijk and Gusto in Schiedam.

Between 1888 and 1935, an impressive total of 274 vessels are built. The fleet includes bucket dredgers, hopper suction dredgers, cutter suction dredgers and trailing suction dredgers, alongside tugboats, rock barges, floating cranes and other support vessels. This fleet reflects a rapidly evolving company. Early bucket dredgers are gradually complemented by more advanced vessel types, supporting larger and more complex works, both inland and at sea.

The Schelde II particularly highlights this development, combining suction and pump technology in a single unit. Larger vessels such as the Gelderland dredgers show the increasing scale of operations, while vessels such as the Rosario dredgers are built specifically for works in South America.