Isaac George Manley sailed with Captain Cook in Endeavour as servant to Robert Molineaux, the Master.  Still a boy, he was promoted to midship­man during the voyage home.  He didn’t sail again with Cook, but rose through the ranks to become Admiral of the Red in January 1837, nine months before he died.1 

Manley married Frances Poole in 1791.  She died in 1837, her death being announced in The Gentleman’s Magazine as,

Oxon.  July 29.  At Braziers, Frances, wife of Admiral I. G. Manley, esq.2

The Gentleman’s Magazine reported Manley’s death with the following obituary,

Admiral J. G. Manley.

Oct. 14.  At his seat, Braziers, Oxfordshire, aged 81, Isaac George Manley, esq. Admiral of the Red, D.C.L. 

He was the last survivor of the crew who sailed with Captain Cook, during his first voyage round the world.  In 1782 he was a Lieutenant on board the Prince George, and took part in the glorious victory gained by Lord Rodney on the 12th of April in that year.

He obtained post rank, Nov. 22, 1790.  In 1796 he commanded the Apollo, a new frigate of 38 guns,
stationed on the Irish coast, where, in company with the Doris, he captured la Legere, a French corvette of 22 guns.  He was advanced to the rank of Rear. Admiral, Oct. 25, 1809.  In the following year the University of Oxford conferred upon him the degree of D.C.L.  He was promoted to the rank of Vice-Admiral in 1814. and to that of Admiral in 1830.

Mrs. Manley died on 29th July last.

His eldest son, John Shaw Manley esq. was married at Florence, July 16, 1821, Catharine-Amelm, daughter of Sir William Clayton, of Harleyford, co. Berks, Bart.

As a country gentleman Adm. Manley was highly esteemed, and is generally and deeply regretted by all classes of society.3 

No biography has ever been written about Isaac Manley, but there has been a biographical novel about him,4 and he featured prominently in a fictional work about a goat that sailed in Endeavour.5 

Ian Boreham

References

1. Cook’s Log, page 11, vol. 30, no. 3 (2007). 
2. The Gentleman’s Magazine.  September 1837.  Page 325. 
3. The Gentleman’s Magazine.  December 1837.  Page 650. 
4. Hill, Anthony.  Captain Cook's Apprentice. Penguin Books.  2008. 
5. French, Jackie.  The Goat Who Sailed The World.  HarperCollins Australia.  2006. 

Originally published in Cook's Log, page 48, volume 39, number 2 (2016).