Dutch ship data in the period of 1628 to 1633

I was amazed when I first saw the Staeten van Oorlog te Water for the years 1628, 1629, 1631, and 1633. For Rotterdam and Amsterdam ships, in many cases, they included lists of guns carried. For the Admiralty of the Noorderkwartier, at best, you had the number of guns, crew, and the size of the ship in lasts. Jan Glete treats lasts as being equivalent to two tons of gross tonnage (volume). That is probably too simplistic, but for his analysis, he needed some measure that would give his burdens in tons for all ships. For "steenstukken", usually just the number are mentioned, perhaps with the number of chambers. Since steenstukken (stone guns) were breach loaders, they could have multiple chambers that could be loaded while one was fired in the gun. The Amsterdam and Rotterdam ships would often specify iron or "metalen" for guns. Many authors, Frank Fox included, assume that these were brass, but Nico Brinck, the Dutch authority on guns, says that they were bronze. You might also see Dutch guns called "kopere", which Nico says were composite guns of copper, iron, and lead, beaten into shape with hammers. Nico says that "klokwijs" guns had a bell-shaped chamber for the powder, which allowed for a smaller powder charge and thinner walls for the gun. Guns might also be just referred to as "chambered", which are similar in concept, with a reduced size chamber for the powder charge. "Drakes" (Draecken) were lightweight guns, which were disliked, as they tended to be more affected by recoil, as they lacked the weight of normal guns.