Green’s Dictionary of Slang

steam-packet n.

a jacket.

1859, 1860		Hotten Dict. of Modern Sl. etc.
1864, 1867, 1870		Hotten Sl. Dict.
1880		D.W. Barrett Life and Work among Navvies 41: Now then, my china-plate, out with your cherry-ripe, off with your steam-packet, and set your bark and growl again.
1890–1904		Farmer & Henley Sl. and Its Analogues.