Frederick was born in 1877 in Chelsea, the son of George Hageman (born in Germany), a carpenter, and Eliza. In the 1891 census Frederick is a sailor in training on the vessel 'Eamouth' in the Thames Estuary off Grays Thurrock, Essex. (Hence his nickname at a guess). I cannot find him or his parents in the censuses from 1891-1911. He married Rose Barber in 1915 and died in 1960.

Pension records
Enlisted - 5th Aug 1914 - 25th Co. London Cyclist - no.1139
Born in Chelsea, aged 34yrs 6mths.
Occupation - Handyman, employed by Fulham Boro' Council.
Address - 30 Al   St, Fulham
Marital status - widower
Discharged 23 Mar 1915 - no longer fit physically for war service.
Next of Kin - Mrs Ellen G..... , mother [Note - his mother was Eliza. There was an Ellen Hageman in the censuses, and considering the lack of a English marriage for his parents and their disappearance from the censuses this may be his aunt]
Pension decision - Rejected.