NavList:

In a prior post I provided this information from "Shackleton's Boat Journey".

Chronometer

“[24^th April] Immediately after breakfast the sun came out obligingly. The first sunny day with a clear enough horizon for rating my chronometer.*

* This English chronometer, an excellent one of Smith’s was the sole survivor, in good going order, of the twenty-four we set out with in the Endurance. [Author’s Note]” p.101

Here's additional reference to the chronometer during their overland trek on South Georgia.

“What the others carried I forget – I carried two compasses, binoculars, food, and the Alpine rope, besides the chronometer, with which I navigated the boat.” p.191

“Sir Earnest asked me for the time. It was 6:55. He said  'We’ll listen for the whaling station’s whistle.’” p. 206

This raises the question. Why would he be have carried the chronometer and not left it at the camp with the other three members of the party if an alternative timepiece was available? (Maybe it was broken, lost, heavier or unreliable)

I find it striking that the impression is given in the popular literature that Harrison built H5 and it was all over but it's clear that even in the early 20th century chronometers weren't that reliable and required lots of care and feeding. The Endurance started out with 24 on board!!!!