With respect to the First Anglo-Dutch War, there are two areas that need to be addressed:
An important, but more secondary issue are more order-of-battle information for both sides in some battles. Typically, either the English or Dutch are well-known, and there is a lack on the other side. At Plymouth, we know the Dutch OOB pretty well, but that for the English is sorely lacking. At the Kentish Knock, we know the Dutch OOB, again, pretty well, but have a less precise view of the English fleet. At Portland, we have pretty complete information about the English, but have only a sketchy idea about the Dutch. in fact, for all of 1653, we have a very poor idea of the Dutch OOB at all the battles.
One thing that can be definitely said is that there are some severe gaps in our knowledge of Dutch ships. That is somewhat true of Admiralty and hired ships. While we have an almost complete knowledge of the Amsterdam Directors' ships, we have very little knowledge about the others.
The sad thing is that we definitely know that more information exists. There is Hendrick de Raedt's pamphlet, at Rotterdam. There is Zeeland director's ship data in the Zeeuwse Archief, but I have not been able to arrange to get reproductions of either, despite trying. There is also a manuscript in the Nationaal Archief, in the Hague, that Rick van Velden was not able to find, but that Jan Glete saw, about 20 years ago. It has some tantalizing ship names (such as Colburg and Harderwijck). I expect that it probably names captains, and this would resolve some of the remaining "holes" in our knowledge.
