Britannic was being constructed in 1913. Her structure ran 852 feet (longer than the Olympic). She was fitted with a double skin hull. It ran for the full length of the boiler and engine room compartments. An extra bulkhead was added to make 17 compartments and five of them were extended to the Bridge deck some 40 foot above the waterline. These modifications should in theory prevent her from sinking in under three hours.
The boiler room and engine rooms were more or less identical to the Olympic except that Britannic turbine engines could generate18,000 horse power. The engines were not built by John Brown & Co as in the case for Olympic but were built by Harland & Wolff.
Her stern would differ from the Olympics because the aft shelter deck was enclosed so that the third class passengers could enjoy a covered area of exterior deck. The third class smoking room was placed above their general room giving the impression that the stern was much bigger.