RMS Titanic - Construction - The Stern: Rudder and Propellers

Source: ANATOMY OF THE TITANIC - Tom McCluskie

Titanic's stern construction was of the schooner, or overhanging, type. The main component was the stern post, on which was mounted the massive five-section rudder. The stern post itself was a huge two-pice Siemens-Martin mild-steel hollow-casting, specially manufactured for Harland & Wolff by the Darlington Forge Company, still in operation today, trading under the name Sheffield Forgemasters.

The stern frame had a total completed weight of 70 tons, to which had to be added the two side propeller shaft support brackets weighing a further 73½ tons. Two forward propeller shaft support brackets, or boss arms, with a combined weight of 45 tons, completed the stern arrangement. When account is taken of the weight of the rivets, etc, attaching these components to the hull, the final weight was approximately 190 tons.

The two sections of the stern frame casting were connect to the after part of the hull using two large scarphs, one mounted on the forward post and one on the after post. A scarph is an insert or filling section of plate designed to connect ajacent sections of material or casting at the stern of a vessel.