The HERCULES a ship of which till today not much is found, some sources give a ship of the East India Company, while I have seen also given as a HMS vessel, but that source is wrong, she was a merchantman and used in the trade mostly from India to South America.
The East India Company lost her monopoly of trade with India in 1813, thereafter they granted licences to ships belonging to private owners, of which many were connected to the British East India Company.
The only HERCULES (what a common name was for ships), used in this timeframe is the one built in Calcutta, by Gilmore & Co., for Fairlie & Co.
27 December 1814 launched under the name HERCULES.
Tonnage 424 ton, dim. 104.5 x 20.3ft.
Used as a licensed ship by the British East India Company, (not a captain name given).
I believe she is depict on the stamp, Log Book gives that the stamp is designed after a print in the National Maritime Museum in the U.K. of an unknown Indiaman.
Very little is known about the early voyages she made, and the voyage she made after her call at Pitcairn in 1819.
17 January 1819 James Henderson rediscovered what is now known as Henderson Island near Pitcairn Island.
18 January 1819 in the morning they arrived off Pitcairn, when within two or three miles of the island, nine young men of the island came out in their canoe.
An account of his visit is given in the Calcutta Journal of 20th July 1819.
On approaching us, the first thing they asked was whether we were a man of war or a merchantman, American or English? On being answered that we were a trading ship under British coulors from India, they came on board.
After breakfast I went on shore at 7 a.m. and was received on the rocks by old Mr. Adams and all the other inhabitants of the island; but not before the islanders that were in the boat with me had given a shout or cry peculiar to themselves to signify my being a friend. I delivered to Mr. Adams the box of books from the Missionary Society of London, and a Letter from Adams brother, who is still living at Wapping, London. I read this letter to him, giving him a description of his family, mentioning the death of one sister, and the prosperity of another. This affected him much, and he often repeated that he never expected to see this day, or indeed one of his countrymen more.
During his visit, Henderson landed a ram, two ewes and a lamb of the South American breed, as well as potatoes, wheat and paddy for planting.
Their greater want was implemented for agriculture, mechanical tools and cooking utensils, of which we could only supply them with one pitch pot, one spade and a saw, with a few knives and forks, some plates, a few pair of shoes and the reading glass of my sextant for old Adams, whose sight was failing.
Captain Henderson took also a letter back for Mr. Adams for his brother in London.
How long he stayed on the island, the book did not give, but most probably they sailed the same day.
Fate of the HERCULES, I found a long time ago a web-site, but did not save it, who did give that most probably the wreck of the HERCULES was found on an island in the Pacific, but a google search did not give any hit more of this site.
Pitcairn Island 1967 1s6d sg68, scott71
Source: mostly copied from The Pitcairners by Robert Nicolson. Ships of the East India Company by Rowan Hackman.