On 21st February 1912, Olympic sailed from New York, heading for Plymouth, Cherbourg and Southampton. At 4.26pm on 24th February, about 750 miles off the Newfoundland coast, she hit what the officers later reported was probably a submerged derelict, not uncommon at that time with so many old wooden-hulled vessels still around. Wooden wrecks would often float for a long time just under the surface, and were notoriously difficult to see in time to take avoiding action. When she hit the derelict, Olympic lost a blade on the port propeller. The engine was immediately stopped and the propeller disengaged to prevent damage to the engine and shafting. Once the damage had been checked, she continued her journey, at a reduced speed, and arrived at Southampton a day late. Once passengers and cargo had debarked, she returned to Belfast, for repairs.
Arriving at Carrickfergus Roads on 1st March, Olympic missed the tide by just 30 minutes and had to anchor overnight. Titanic had been withdrawn from the drydock on 29th February, in readiness for the arrival of Olympic. As soon as the damaged liner was docked, workers were transferred from Titanic to complete the repairs. The opportunity was also taken to clean and repaint the lower hull.
Once complete, Olympic left the drydock on 4th March. However weather conditions were bad, and she was unable to head for the Victoria Channel. It was decided to return her to the drydock until the gales eased, as room in the yard was very restricted. The next day Harland & Wolff achieved a novel, very tricky manœuvre: they moved Olympic out of the drydock, eased Titanic into the drydock and then moved Olympic to the fitting-out wharf, all on the one high tide. The next day, 7th March, weather conditions had improved sufficiently for Olympic to leave Belfast and head for Southampton. On leaving, she briefly went aground near West Twin island, but was cleared to sail after divers had checked the hull. However, work on Titanic had been delayed and this was to have an impact on the later disaster.