He specializes in shipwreck archaeology and is interested in developing and furthering recording methodologies in the field of maritime archaeology. In his master thesis and later also in his PhD, he focused on the archaeology and history of small warships in the Danish navy between 1650 and 1750. One of his recent fieldwork projects included the excavation and analysis of the Swedish man-of-war Princes Hedvig Sophia, which was lost during the Great Northern War. Jens is also associated with the commercial diver training centre, where he teaches commercial diving courses.