Actually earlier - the Lunar method was reliably used by Cook and Shackleton. It was only on Cook's 2nd and 3rd voyages that he had K1, the first replica of H4

Actually earlier - the Lunar method was reliably used by Cook and Shackleton. It was only on Cook's 2nd and 3rd voyages that he had K1, the first replica of H4 - Harrison's watch - that Cook referred to "My trusty friend, the watch."