She supported the landings at Sedd el Bahr on 4 March. These consisted of two companies of Marines, each landing at their beach. "Ocean" was tasked with supporting the northern company that landed at Sedd el Bahr. The southern group, tasked with capturing the coastal town of Kumkale, came under heavy fire as soon as they went ashore. The northern group encountered similar resistance, but "Ocean"s gunners, more experienced from their operations of Basra the previous year, proved to be more effective than the other ships. Nevertheless, both companies were forced to withdraw, in large part because they were too small to break through the Ottoman defences. Another bombardment followed on 6 March; "Ocean" and the battleship were tasked with covering the powerful superdreadnought battleship while she engaged the Ottoman artillery batteries. After a day's bombardment, the British sent in minesweepers to try to clear the minefields blocking the strait, and "Ocean", "Majestic", and several destroyers were tasked with protecting them. Despite the heavy bombardment, the Ottoman defenses were largely intact, and even concerted firing from "Ocean" and other ships could not suppress the guns or their search lights. Early on 7 March, the British were forced to withdraw.