Clementsen was employed as a master at the Royal Danish Navy Construction School at Holmen. He did a number of paintings but never signed them. This one of the frigate "Frederiksborg Slot" ("Frederiksborg Castle") is almost certainly his work. The ship belonged to "Det Asiatiske Compagni" (DAC) ("The Asiatic Company") and is painted with surroundings that might be the Cape of Good Hope.