At the end of the expedition it took the combined efforts of two relief ships and the use of explosives to free "Discovery" from the ice. Scott's insistence during the expedition on Royal Navy formalities had made for uneasy relations with the merchant navy contingent, many of whom departed for home with the first relief ship in March 1903. Second-in-command Albert Armitage, a merchant officer, was offered the chance to go home on compassionate grounds, but interpreted the offer as a personal slight, and refused. Armitage also promoted the idea that the decision to send Shackleton home on the relief ship arose from Scott's animosity rather than Shackleton's physical breakdown. Although there was later tension between Scott and Shackleton, when their polar ambitions directly clashed, mutual civilities were preserved in public; Scott joined in the official receptions that greeted Shackleton on his return in 1909 after the Nimrod Expedition, and the two exchanged polite letters about their respective ambitions in 1909–1910.