Stemat Marine Services was a service company (within the VolkerWessels group) for maritime work, based in Rotterdam, Netherlands. Stemat started with a few vessels in 1986, expanding to a fleet of more than 50 vessels. In the port in Rotterdam, Stemat had over 14,500m² of harbor space, 160m of wharf, frontage, and 13,500 m² of storage space. The wharf was equipped with mobile cranes with a hoisting capacity of up to 23 tons. Stemat owned a wide variety of modern equipment, including multi-purpose vessels, crane barges, pontoons, pushers, and tug boats. In 2016, Stemat was acquired by Boskalis.