Yeah but why did it sink faster than Titanic?
Answer:
Britannic was launched just before the start of the First World War and was laid up at her builders in Belfast for many months before being put to use as a hospital ship in 1915. In that role she struck a mine off the Greek island of Kea on 21 November 1916.
The explosion had blown a large hole into the forward bow, at the bulkhead between holds 2 and 3. The bulkhead between the first and second holds was damaged beyond use. The watertight door in the fireman’s passage was destroyed. As a result, boiler room 6 began taking on water. On the bridge, Captain Bartlett was not as confident in his ships abilities as Captain Smith had been with Titanic’s and immediately instructed the radio operator to send out a distress call and ordered the lifeboats uncovered and sounded the general alarm.
There had only been one explosion, so it was possible that the flooding could be contained to the forward hull. It was soon learned that the watertight door between boiler rooms 5 and 6 had malfunctioned, despite its distance from the explosion. Water was pouring into six of the forward compartments. The damage to Britannic was eerily reminiscent of the wound inflicted on Titanic by an iceberg two and a half years earlier, however with the addition of the higher bulkheads that topped Britannic’s watertight compartments off, the holds aft of boiler room 5 held and prevented the domino effect that had doomed her older sister. But soon, under this tremendous weight of water, Britannic was listing heavily to starboard. Many of the portholes on the upper decks had been opened to air out the stuffy wards. This was a serious breach of protocol in a war zone. The list was soon enough to plunge the portholes on E and F decks below the waterline and water poured into the ship which increased the list even more, Captain Bartlett then made a critical error which sealed Britannic's fate. Only three miles away was the island of Kea and which had large shallow coastal sandbanks which could have offered salvation. If he could ground Britannic on the sand, she could be salvaged so he ordered the engines full ahead and in combination with the rudder and increased power on the port-engine Britannic began to turn for the sandbanks.
As the massive liner accelerated, so did the flooding of her forward compartments. The list increased dramatically and Bartlett realized there was no chance of reaching the island and ordered the engines stopped. Before Britannic could slow down, two lifeboats were launched without authorisation from the port side. Carrying about seventy people between them, the boats were drawn into Britannic’s still churning propellers and thirty people met a gruesome end being churned up in the massive blades. Up on the boat deck, the rest of the crew assembled in what was, for the most part, an orderly evacuation. It became clear very quickly that the ship was going to sink much faster than Titanic had, but the waters were warmer and there were far fewer people on board; less than half as many. It wasn’t long before Britannic’s bow was submerged and she began to roll onto her side. The engineering crew, including the chief engineer himself, escaped through the specially prepared evacuation route made for them up the fourth funnel. Britannic sank at 09:07, only fifty-five minutes after the explosion.
Britannic suffered much heavier damage than the Titanic, with six compartments flooded the Titanic would have sunk much quicker, the Britannic however would have stayed afloat had the portholes not been left open and the intake of water vastly increased by the attempt to beach the ship. Some testament at least, that her improvements would have prevented the Titanic from sinking.