Complex sentence: On 18 November 1776, off Cape Finisterre, she seized a South Carolinian merchant ship with a cargo of rice and indigo worth £37,200, or £4.5 million in 2015 terms.
Split into simpler sentences: On 18 November 1776 she seized a South Carolinian merchant ship off Cape Finisterre. According to contemporary accounts the captured ship was carrying a cargo of rice and indigo worth £37,200, or £4.5 million in 2015 terms.