sentences:  Shortly after the marriage, the oldest of Neeltje's daughters had a child of her own, and so at only 23 years old Dorus became known as 'Opa' in Den Helder where he lived.Although the nickname began as a joke, Dorus soon started acting and looking like a grandpa, and from that time on he became primarily known by his nickname.Dorus gained most of his fame as a result of his service to the Noord- en Zuid-Hollandsche Redding Maatschappij (NZHRM), one of the two main Dutch lifeboat-societies at the time.