[3] The hydrographic survey vessels of the Dreg I class were all built at the shipyard of De Groot & Van Vliet in Slikkerveer.

[2] For surveying the vessels were equipped with echo sounders and marker buoys that were shaped as spheres.

[4] In November 1950 two vessels of the Dreg I class were transported from the Netherlands to Dutch New Guinea by ship.

[3] In 1963 the Dreg I-class hydrographic survey vessels were active in the North Sea to collect data that would help determine the safest waterway to the Europoort.

[6] In 1966 three Dreg I-class survey vessels were used to map a part of the IJsselmeer between Staveren and Lemmer.