RMS Titanic - Construction - Superstructure

Source: ANATOMY OF THE TITANIC - Tom McCluskie

The Titanic had a classic triple-deck superstructure, the uppermost decks comprising the Boat, Promenade and Bridge decks. These three superstructure decks were constructed incorporating the same build specification as the materials used in the hull and internal structure. Normal shipbuilding practice permitted the use of lighter materials in the construction of the accomodation or superstructure above the main deck, on Titanic the Shelter deck. By using lighter materials for construction in this part of the vessel, several advantages could be gained, the two most important rising from the weight reduction achieved. Less superstructure weight meant the vessel was less susceptible to rolling in heavy seas, something exacerbated by being “top heavy”. Second, the reduction in vessel weight permitted a greater service speed to be achieved without the need to increase engine horsepower.

Neither of these factors was a condideration in the case of Titanic, because White Star was not overly interested in speed and it was felt that Titanic was substantial enough to withstand heavy seas. So, the upper superstructure decks were constructed to the same criteria as the hull and internal structure to ensure the utmost degree of structural rigidity. The deck sides were supported on specially built-up frames placed in line with every other hull frame below.

The deckhouses themselves were stiffened internally by the inclusion of channel-section steel bars fitted into the steel framework. In addition to these channel bars, heavy support brackets were incorporated into the structure where the requirement to create open public spaces penetrated the internal deck structure.

These brackets were designed to compensate for the loss of structural material in these areas and to provide increased strength against the torsional or twisting stresses present in the hull, particularly when steaming through heavy seas.