Jacob Sikkes Spoelstra, born circa 1855 (?).

Jacob was married to
Gertje Harmens van der Kooi, born circa 1859 (?).

• 1 : Rinse Spoelstra, born in Sneek on February 11, 1882, died there on April 7, 1957, aged 75 years.
  Rinse was married in Sneek on November 18, 1911, at the age of 29 to Hielkje Steginga (aged 35 years), born in Harlingen on December 11, 1875, daughter of Siebolt Lammerts Steginga (bargeman) and Fokje Johannes Feenstra, died in Sneek on January 11, 1966, aged 90 years.
  Hielkje was widow of Hendrik van Ossenbruggen, died before August 23, 1907.