In 1712 Claas and Hendrickie were living in Oudebildtzijl. In baptismal books Claas is listed with two different last names: Kaaps (in 1716 and 1726) and Pluimer (in 1721, 1723, 1725, 1728, and 1732). In Dutch, "Kaap" and "Kaper" mean some sort of hat. The old Dutch word "pluimer" refers to feathers. These names could have been related to his profession.