Shackleton used his acquaintance with the son to obtain an interview with Longstaff senior, with a view to obtaining a place on the expedition. Impressed by Shackleton's keenness, Longstaff recommended him to Sir Clements Markham, the expedition's overlord, making it clear that he wanted Shackleton accepted. On 17 February 1901, his appointment as third officer to the expedition's ship was confirmed; on 4 June he was commissioned into the Royal Navy, with the rank of sub-lieutenant in the Royal Naval Reserve. Although officially on leave from Union-Castle, this was in fact the end of Shackleton's Merchant Navy service.
shackleton used his acquaintance with the son to obtain an interview with longstaff senior with a view to obtaining a place on the expedition impressed by shackleton's keenness longstaff recommended him to sir clements markham the expedition's overlord making it clear that he wanted shackleton accepted on 17 february 1901 his appointment as third officer to the expedition's ship was confirmed; on 4 june he was commissioned into the royal navy with the rank of sub-lieutenant in the royal naval reserve although officially on leave from union-castle this was in fact the end of shackleton's merchant navy service