After the signing of the 1848 Convention between Britain and the United States there was only one semieffective American steamship line on the North Atlantic - the Ocean Line. This soon changed. The Collins Line was the first addition in 1851, but between 1855 and 1857 there were four. By 1862 there were none and despite a brief revival at the end of the Civil War the same situation existed in 1868
1846, MASSACHUSETTS: Folded letter dated "London 17 Jan 1846" to New York, paid "8"d. outgoing ship letter fee with red "PAID SHIP LETTER LONDON 17 JA 17 1846", upon arrival "6" cents ship fee charged, interesting entire from the last out of only four voyages