A confusing piece of information

In Schetsen uit de Geschiedenis van ons Zeewezen, there is a notation that Joost Bankert's ship was captured after he was killed. In a letter dated 3 March 1653, there is a notation that Joost Bankert was dead, but his ship was with the 17 Zeeland ships, which I believe were heading for Vlissingen after the Three Days Battle (the Battle of Portland).