I have been immersed into thinking about Frisian ships today (thanks to finding the website). Now, I wonder again if the ship purchased in 1652 as the Groenewold actually served as the Zevenwolden? There is no sign of the Groenewold, except for the mention in the "Staet van Oorlog te Water" for 1654 and in "Vreugdenhil". Now, the Zevenwolden was lost at Scheveningen, but as I have indicated, the Groenewold shows in the "Staet" for 1654 and in Dr. Elias' book in a list from 1655. There is also a listing for Claes Jansoon Sanger and the West Cappel in both 1654 and 1655. Of course, the West Cappel was also taken and burnt at Scheveningen.
The other thing I wonder about is the Groningen. The Friese website says that Hendrick Janszoon Camp commanded the Groningen at Dungeness, and that it was the same 36-gun ship that fought at the Battle of the Sound in 1658 (as well as participating in the rest of the First Anglo-Dutch War). If that is correct, than the ship was built prior to 1653, unlike what Dr. Weber said in his book about the Four Days Battle. The ship is often shown with a smallish crew, so perhaps this was the ship from the March 1653 list that had 110 men in the crew and the Zevenwolden was the one with a 140 man crew.
We shall see how this develops, as I continue to gather more information.