Indefatigable was a square-rigged, three-decked, three-masted merchant ship launched in 1799 at Whitby for James Atty & Co. for the West Indies trade.

She twice transported convicts to Australia; on the first trip she was chartered to the British East India Company (EIC).

Following the resumption of war with France in early 1803, concern developed in Britain about Napoleon's planned invasion of the United Kingdom.

The British East India Company in November voted to underwrite 10,000 tons (bm) of armed transports to protect Great Britain's coasts.

The vessels were: Albion, Anacreon, Atlas, Aurora, Chapman, Diadem, Duckenfield, Helder, Indefatigable, Lord Forbes, Lord Nelson, Norfolk, Paragon, Perseus, Robert, Sir Alexander Mitchell, Suffolk, and Triton.

On 10 April 1804 the armed transports Indefatigable, Albion, and Duckingfield, were ordered to St Helen's to maintain a guard there until HMS Queen could relieve them.

[10] She arrived at the Cape on 6 August,[8] Indefatigable had been at Canton, where she had loaded a modest cargo of tea and no textiles.

British ships were then free to sail to India or the Indian Ocean under a licence from the EIC.

[3] While anchored at Batavia (now Jakarta), Indefatigable was burnt to the waterline in an accident on 23 October 1815 and declared a total loss.