FAQs
(Capabilities)
Was Titanic trying for a new speed record on her maiden voyage?
Yes and no. The Olympic-class ships were not built to compete for the Blue Ribband with the speedy Cunarders, Lusitania and Mauretania. Ismay sought instead to uphold White Star's reputation for providing the best customer service on the North Atlantic. However, the fact that Ismay's triplets would be designed so as to emphasise care over speed does not mean that the Managing Director of the OSNC was unmindful of the need for keeping to a regular schedule. The Olympic-class ships could maintain a respectable crossing time, as triumphantly evidenced by Olympic's time recorded for both the westward and eastward legs of her maiden voyage. In order to keep the publicity momentum rolling for Titanic, it was considered imperative that the second ship better her older sister's time. Corroboration for this may be found in a relayed telegraph message that was printed in the Ships' Arrival column of the 15 April edition of the New York Times, before the disaster became publicly known. The Sandy Hook wireless telegraph station reported that Titanic was due to arrive at a new time of 4 P.M. in the afternoon of the 16th. Although arriving at her originally scheduled time on the morning of 17 April would just beat Olympic's time, the new arrival time well over half a day earlier would focus the public's attention on the new liner's speed. Whether or not this new reported arrival time could have been realised or not, there is every indication that the crew and owners of Titanic expected her to better her elder sister's time for completing the westbound leg of her maiden voyage. So, even though Titanic would not be challenging any speed records, she could better Olympic's time, proving to the paying public that each ship built by the White Star Line would outperform the one previous. There is nothing nefarious in this...it's just good business. Unfortunately, this attitude helped shape Smith's decision to proceed at full speed through a region where ice had been reported.
Was Titanic's rudder too small to be effective?
Where rudders are concerned, bigger is not always better. It's true that the larger the rudder, the more surface area there is to generate hydrodynamic torque, but larger rudders also generate more drag and require more pressure from the steering engines to turn them effectively. British naval architects during the first part of the century appear to have preferred the unbalanced rudder for merchant ships, where the blade of the rudder is entirely aft of the stock. This places the centroid of pressure (CP) relatively far out on the blade, increasing the pressure required by the steering engines to move the rudder. The balanced rudder was used for Lusitania and Mauretania (one that places the CP on the stock by having a portion of the blade ahead of the stock), but design of the stern for those two ships was dictated by Admiralty requirements. Other factors affecting a rudder's design will be familiar to aviators...tip vortices (similar to cavitation), induced drag and stall. Another consideration was protection against grounding damage.
So what was the ideal design? To quote Lovett (W.J. Lovett's Class-Book of Naval Architecture, London, 1905), "Even the highest authorities are at variance in respect to the best form of rudder." The White manual (W.H. White's Manual of Naval Architecture, London, 1900) discussed four of the more common rudder shapes in use by the Royal Navy (one balanced, three unbalanced) and weighed the pros and cons of each, comparative to the hull to which they were normally attached. For the rudder shaped like Titanic's, White mentioned that it was "a form now commonly used in the steamships of the Royal Navy," and that one major advantage of its shape was that "by tapering the rudder, the power required to put the helm over is made considerably less...these considerations would not have equal force in screw steamers where the rudder is placed abaft the screws; and then the form [of the rudder here under discussion] is to be preferred." The rudder shape accepted by the H&W architects therefore appears to have been a compromise (as most rudder designs were at that time) between weight and surface area, while taking advantage of the position of the centre screw and providing protection against potential grounding.
So, was Titanic's rudder big enough? White stated that "for steamships...the extreme breadth of the rudder [is often] from one-fortieth to one-sixtieth of the length...in merchant ships much smaller rudders are used, and values as low as one-hundredth have been met with." Without running a model in a tow tank, one can only judge by dimension and compare to White's stated guidelines. Titanic was 850' long along the waterline, her rudder was about 15' wide at the fullest part of the blade. That made it about one-fiftyseventh of the length and therefore followed White's rule of thumb.
Would a Titanic II have a differently-shaped rudder? According to the conceptual model published in Popular Mechanics, it would be much enlarged from the original. However, the shape of an enlarged rudder not only requires more powerful steering engines, but also introduces the risk of stalling the rudder at extreme rudder angles. Again, going back to White, he cautioned that (in a given example) a "broad rudder, with an area 37 per cent. greater than the narrow one, has therefore less turning effect by about 11 per cent."
There's no set standard for determining what the optimal shape for a rudder for Titanic ought to have been. Oftentimes, rudder shapes were determined by copying a shape that worked well for another ship of similar dimensions. But, given the methodology laid out in the contemporary Naval Architecture books, it appears that Titanic's rudder was of adequate design to effectively manoeuvre the ship.