The two small Rotterdam frigates Overijssel and Utrecht

I was looking at the two small Rotterdam frigates from 1638 that are usually listed with their dimensions in Maas feet (100ft x 23ft x 8ft). I estimate that their dimensions in Amsterdam feet were 109ft x 25ft x 8.75ft. The two ships had quite different armaments (we know them from the 1654 list). They both had 22 guns, but composed from quite different selections of guns. The Overijssel carried 6 brass guns (4-chambered 24pdr and 2-light 12pdr) and 16 iron guns (4-8pdr and 12-6pdr). The Utrecht also had 6 brass guns (6-chambered 12pdr) and 16 iron guns (10-8pdr, 2-6pdr, and 4-4pdr). The broadside weight for the Overijssel was 112lbs while the broadside weight for the Utrecht was only 90lbs. The Overijssel had an armament weight of no more than 21.87 tons. The Utrecht had an armament weight of no more than 18.74 tons, probably much less than that. These weights don't take into account the weights of chambered pieces, so they should be considerably less than what I have listed here. The Overijssel made sacrifices to get the 4-24pdr guns, as she only had 10 guns of 8lbs shot and above. The Utrecht didn't have the large guns, but did have 16 guns of 8lbs shot and above. The interesting 26 February 1652 Admiralty of Rotterdam list indicates that there was a third ship of this class, the Gelderland. She had identical dimensions but only had 20 guns of unknown sizes. It is hard to know if this data was correct, as this is the only reference that lists a 20-gun Gelderland.