One thing he found was that Jacob Cleijdijck's ship that was sunk at the Battle of Portland on February 28, 1653, was named the Meerman. We know from other sources that the Meerman carried 30 guns and had a crew of 120 men. The Meerman was a Director's ship of Rotterdam (or the Maze).
Another piece of information that Carl Stapel pointed me to was in Captain Warnsinck's book about Pieter de Bitter. In there, we find that Pieter de Bitter commmanded the Mercurius, a VOC ship, in 1653. The Mercurius carried 40 guns and had a crew of 200 men, according to Captain Warnsinck.
Then, there is a list of five Admiralty of Amsterdam ships that left for the Mediterranean in March 1650, under the command of Johan van Galen:
Ship Built Guns Crew Captain Maen Jan van Galen Leeuwarden 1645 34 130 Gideon de Wildt Morgenster 1644 28 110 Cornelis Tromp Ver. Prov 1643 36 140 Hendrick Swart Hazewind 1649,jacht 16 80 Cornelis van Velsen