Joseph William Jackson was my Great-Grandfather. I knew that he was somehow related to the Coastguard from the 1910/1911 Census, but have just discovered his Naval Record/Service Number which shows that from 1890 his 'Rating was changed from 'Stoker' to 'Boatman' and then, in 1910 to 'Petty-Officer CG'. 'CG' presumably meant Coast Guard. He was moved around various Coastguard Stations on the south-coast of England and later to Ireland - Portmuck, Omeath, Soldier's Point, Giles Quay. I know nothing of the history of the Coastguard Service but a websearch led me to here.