|THE TWENTY-ONE KNOT MYTH
by Mark Chirnside:
In the history of ocean liners it is rare to hear of a ship having its speed limited. Rather it is more common to hear of ship owners making efforts to increase the speed of their ships, while aiming to maintain the same rate of fuel consumption or even reducing consumption to ensure increased economy of operation. This may be done in a variety of ways, propeller reengineering and condenser modifications being two possibilities - indeed, the latter was experimented on in 1934 with the Aquitania. However, despite modifications to the ships condensers, which from then onward allowed the ship to make twenty-four knots, the propellers were not suited to the higher speed and had to be modified owing to the additional slip created.
Olympic will be the focus of this article. It is well-known that as one of the White Star Lines Olympic class, she was designed for comfort as a good sea boat, combined with luxury rather than the speed of an ocean greyhound. The economic arguments against the operation of such greyhounds are well known and require no further extrapolation here. Thus Olympics design allowed for her to maintain a service speed of twenty-one knots over the ground in practically any weather, for the North Atlantic is famed for its harsh treatment of ships. In the event, when she had entered service she had proved herself considerably faster, soon making crossings at up to 22.5 knots with ease. Her conversion to oil firing by her return to service in 1920 following the war ensured her continued excellent performance, one of the many advantages of the oil system being that steam pressure could be much more easily regulated and maintained. Steam pressure did not require hundreds of energetic stokers.
Yet, although Olympics excellent performances are well-known, there is a belief about her that I feel to be untrue: her so-called limitation to a twenty-one-knot service speed after her refit in late 1932 and early 1933.
I have tried to locate primary source documentation confirming that Olympics speed was limited from 1932. Although I have found some material on the topic, I believe that there is good ground for assessing that its meaning is questionable, or certainly speculating upon it.
Many TRMA members will be aware of the purpose of Olympics 1932 refitting, but nonetheless it is worth recording a summary here. As the ships fourth major refitting in a quarter-of-a-century of service, changes were made to the vessels accommodation in order to modernise the ship and attract a greater number of passengers, since the ship was by 1933 in her twenty-second year of service. Aside from these changes, substantial work was completed on the ships two reciprocating engines in order to renew crankshafts, add bearings, and generally further improve the balance and performance of the engines.
It is as this engine work was going on that the following statement was printed on the Olympics record, dated November 9th 1932:
It is hoped that the reduction of the speed to 21 knots, decided upon by the owners, will do much to mitigate the stresses to which the vessel has been subjected.
This vague statement speaks of a reduction of the speed, although twenty-one knots would certainly be a limitation of Olympics potential. Ships in service experience many stresses, especially on the Atlantic, but it is questionable whether the person is noting those experienced by the ships engines, or other aspects of her anatomy.
To assess whether the engines were being referred to or not, we need to deal with other aspects of the Olympic. In early 1931, Olympic underwent significant repairs to her superstructure and upper works, following a terrible winter of heavy weather, and this included welding around the drainage holes beneath her portholes on the bridge and shelter decks to repair fatigued plating, and the fitting of doublers in several areas. (Interestingly, Aquitania was having similar repairs at the same time.) There were concerns as to the ships long term seaworthiness and the experimental nature of the repairs - after all, welding was only then coming into use for ship construction. However, by the spring of 1932 these doubts were disappearing:
The vessel is under running survey, the whole of which has now been completed, and she has been dry-docked and drilled this month. The general condition is good, but certain defects have been manifested within the past few years.
As usual, the ships passenger certificate was issued for twelve months that year, in contrast to the two-part certification of 1931. From 1933 no notable defects whatsoever were reported and the ship enjoyed a trouble free life for the remainder of her service. It therefore seems unlikely that it was felt in November 1932 necessary to mitigate stresses to which the ships hull was subjected in normal service.
At the time, Olympics engines were being worked on and indeed the first quote appears in the middle of the record of engine maintenance, rather than any other aspect of the ship. Therefore it might seem reasonable to suppose that the reduction in speed was for the benefit of the ships engines. One official who was not aware that the ships engine bedplates had needed repairs was concerned because such problems were usually associated with the longitudinal working of the hull structure. However, he made a personal visit to the ship and concluded that there was no cause for alarm on November 10th 1932, the day after it had apparently been decided to limit the ships speed to twenty-one knots. Might it be that this reassurance had made a proposed reduction in speed unnecessary?
In any case, having gone through the surveys of the entire Big Six - Mauretania, Olympic, Berengaria, Aquitania, Homeric and Majestic - as well as the Leviathan, I concluded that a speed reduction for the Olympic was even more unlikely. All of the other ships were suffering similar problems to the Olympic, and in a number of cases Olympic was in better condition. Yet none of them ever had speed restrictions slapped on them. Furthermore, the possible speed reduction had been considered by White Star, rather than the Board of Trade, and this lends credence to the Board of Trade not considering it necessary, particularly after the officials visit to Olympic on November 10th 1932, when he was reassured.
Following this date, various reports appear commenting on the work done to the ships engines. One confirms the various casing pressures, before commenting that the revolutions would normally be seventy-eight per minute. Such a number appears to confirm acknowledgement that the ship would be run at well over twenty-one knots, for seventy-eight revolutions would produce up to twenty-three knots in good conditions, were the ship aided by the gulf stream. There is also much documentation as to the completion of the work - it is clear that by the time the ship returned to service in March 1933, the vessels engines were performing better than they had ever done before. It is also clear that the engine work had been more successful than had ever been expected.
Aside from speculating upon the reasons for a proposed speed reduction, based itself on one single source, it is undisputable that Olympic continually exceeded twenty-one knots following 1932, just as she had done before. In fact, she set a new record for herself personally in 1933 for three consecutive crossings. Although the White Star Lines claim in spring 1933 that the ship would have a new service speed of twenty-three knots seems hyperbole, none of the available evidence supports the contention that Olympics speed was reduced following the 1932 refitting. Based on one reference, which seems hard to interpret, and is contradicted by many other primary sources, it is clear that Olympic maintained her excellent average speeds after 1932 and was not limited in her speed, even if such a limitation might have been considered. Furthermore, the ship consumed less fuel at twenty-two knots than twenty-one according to several records from 1935 and so there would have been no advantage from an economic viewpoint either.
It is often hard to try and interpret sources, for we need to know their context and scope. Although it is true that a proposal to reduce the ships speed was under consideration, we can conclude that it was not acted upon, for no such reduction was seen in the ships service; it is clear that the proposal came from the White Star Line, and was entirely voluntary in any case; it is also clear that the ships engines were performing better than ever before from this refit; and that the ship was still averaging more than her maiden voyage speed in 1935. On her final voyage, her average speed was only lower than that of her maiden voyage by one-tenth of a knot. Such an exploration seems to indicate how easy it is for misinformation to circulate, for the fact that Olympics speed was limited to twenty-one knots from 1932 has been reported widely in articles, on the internet and as far and wide as Germany, sources which appear to copy each other constantly. Yet the evidence in support of it is solitary and questionable in its meaning, while voluminous primary source evidence directly contradicts such an assumption. With Titanic, myths have been circulating for ninety years; but with Olympic, interest is only slowly growing and has been for fewer years. Therefore we have the opportunity to try and correct myths before they become truly embedded in the story of the ships glorious history.