Endurance, without Shackleton (who was detained in England by expedition business), left Plymouth on 8 August 1914, heading first for Buenos Aires. Here Shackleton, who had travelled on a faster ship, rejoined the expedition. Hurley also came on board, together with Bakewell and the stowaway, Blackborow, while several others left the ship or were discharged. On 26 October, the ship sailed for the South Atlantic, arriving in South Georgia on 5 November. Shackleton's original intention was that the crossing would take place in the first season, 1914–1915. Although he soon recognised the impracticality of this, he neglected to inform Mackintosh and the Ross Sea party of his change of plan. According to the Daily Chronicle's correspondent Ernest Perris, a cable intended for Macintosh was never sent.After a month-long halt in the Grytviken whaling station, Endurance departed for the Antarctic on 5 December. Two days later, Shackleton was disconcerted to encounter pack ice as far north as 57° 26′S, forcing the ship to manoeuvre. During the following days there were more tussles with the pack, which, on 14 December, was thick enough to halt the ship for 24 hours. Three days later, the ship was stopped again. Shackleton commented: "I had been prepared for evil conditions in the Weddell Sea, but had hoped that the pack would be loose. What we were encountering was fairly dense pack of a very obstinate character".Endurance's progress was frustratingly slow, until, on 22 December, leads opened up and the ship was able to continue steadily southward. This continued for the next two weeks, taking the party deep into the Weddell Sea. Further delays then slowed progress after the turn of the year, before a lengthy run south during 7–10 January 1915 brought them close to the 100-foot (30 m) ice walls which guarded the Antarctic coastal region of Coats Land. This territory had been discovered and named by William Speirs Bruce in 1904, during the Scottish National Antarctic Expedition. On 15 January, Endurance came abreast of a great glacier, the edge of which formed a bay which appeared a good landing place. However, Shackleton considered it too far north of Vahsel Bay for a landing, "except under pressure of necessity"—a decision he would later regret. On 17 January, the ship reached a latitude of 76° 27′S, where land was faintly discernible. Shackleton named it Caird Coast, after his principal backer. Bad weather forced the ship to shelter in the lee of a stranded iceberg.They were now close to Luitpold Land, discovered by Filchner in 1912, at the southern end of which lay their destination, Vahsel Bay. Next day, the ship was forced north-westward for 14 miles (23 km), resuming in a generally southerly direction before being stopped altogether. The position was 76° 34′S, 31° 30′W. After ten days of inactivity, the ship's fires were banked to save fuel. Strenuous efforts were made to release her; on 14 February, Shackleton ordered men onto the ice with ice-chisels, prickers, saws and picks, to try and force a passage, but the labour proved futile. Shackleton did not at this stage abandon all hope of breaking free, but was now contemplating the "possibility of having to spend a winter in the inhospitable arms of the pack".

Question: On what sea was Shackleton from January 7-10 in 1915?
Answer: Weddell