| Great Eastern. | Mauretania. | |||
|---|---|---|---|---|
| Length | 692 | feet. | 790 | feet. |
| Breadth | 80 | „ | 88 | „ |
| Displacement | 27,000 | tons. | 45,000 | tons. |
| Paddle, screw, and sail. | Quadruple screws. | |||
| Speed | 13 to 14 | knots. | 25 | knots. |
“The Great Eastern was an experiment, but there is nothing of the experiment about the Mauretania and her sister, the Clyde-built ship Lusitania. The valuable data obtained from the running of the 20,000-ton turbine Cunarder Carmania has afforded a valuable object-lesson in adapting the turbine method of propulsion to liners of the leviathan class, demonstrating the suitability of the steam turbine to the largest type of vessel.
“The Mauretania is propelled by turbine engines of about 70,000 indicated horse-power, driving four shafts, each of which is fitted with one three-bladed propeller of manganese bronze. The outermost shafts are each connected with a high-pressure turbine, the inner shafts being rotated by the low-pressure turbines.
“The boilers and turbine engines of the Mauretania were constructed by the Wallsend Slipway and Engineering Company, Ltd., of Wallsend-on-Tyne. There are twenty-three double-ended and two single-ended boilers, and one hundred and ninety-two large furnaces. The boiler plates are the largest yet made. The steam is conducted from the boilers into the turbines, of which there are four.” The turbines contain about 3,000,000 blades, rotating four shafts, the united length of which is close upon 1000 feet with a weight of about 250 tons, each shaft carrying 17,000 or 18,000 indicated horse-power. Under the covenant with the Government made at the time she was arranged to be built, she is fitted for an armament of 12 six-inch guns. Her rudder and both sets of steering-gear are below the water-line, and in the way of the engine and boiler rooms there are side bunkers which, filled with coal, are equivalent to an armour-belt round the vulnerable portion of the ship.
Although the Mauretania and Lusitania are usually spoken of as sisters, there are some differences in the design. They are the same length, but the former is six inches deeper, which adds about 500 tons to her registered tonnage. Special high tensile steel was used to a greater extent in the construction of the Mauretania, making that vessel something like 1000 tons lighter. Her lines are slightly finer, and it has been claimed to account for her speed that there is some superiority in her engines.
In regard to the structure of the Lusitania, it is stated that with the whole structure of mild steel Lloyd’s accepted a stress of ten tons to the square inch, and that in view of the strains thrown upon the upper works a high tensile steel of less scantling was adopted for those parts; a material having been discovered with a tensile strength 20 per cent. greater than mild steel, a reduction of 6 per cent. in the scantlings was allowed from those for mild steel. The Cunarders were not the first vessels by many years in which high tensile steel of a strength of thirty-six tons was used, as it was introduced twenty-three years ago in the steam-ship America.
Whether the great Cunarders pay in the financial sense is known only to the management of the line, but there is no denying that they are a great national asset. A detailed estimate, published at the time they were about to make their first voyages, placed the expenditure at £17,990 per voyage, and the income, allowing for a full passenger list, at £31,350.[91] But this did not profess to be more than a general estimate and in no sense official. The question has been raised in various quarters whether an equal speed could not have been obtained from reciprocating engines with a less consumption of coal; as a reply to this view it has been pointed out that the sizes that would have been required for the ingots, &c., for the machinery were beyond the capabilities of our steel manufacturers, and thus, as so often has happened, the new set of conditions was met by the new development of invention.
[91] Liverpool Courier, November 18, 1907.
| Campania. | Oceanic. | Baltic. | Kaiser Wilhelm II. | Lusitania. | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Displacement | 20,000 | 26,100 | 33,000 | 26,000 | 41,500 | |||||||||
| Draught | 30 | 30 | 30 | 30 | 32 | |||||||||
| Speed | 22 | 20 | 16 | ¹⁄₂ | 23 | ¹⁄₂ | 25 | |||||||
| I.H.P. | 30,000 | 29,000 | 16,000 | 38/40,000 | 65,000 | |||||||||
| Consumption of coal, tons per day | 485 | 400 | 260 | 660 | 840 | |||||||||
| Length, b.p. | 598 | 685 | 709 | 684 | 760 | |||||||||
| Breadth | 65 | 68 | ·3 | 75 | ·6 | 72 | ·3 | 88 | ||||||
| Depth | 43 | 49 | 49 | 52 | ·6 | 60 | ·5 | |||||||
| Gross tonnage | 12,950 | 17,274 | 23,800 | 19,360 | 28,830 | |||||||||
| Number of boilers | 13 | 16 | 8 | - | 12 double 7 single | - | 24 | |||||||
| Total cost | £615,000 | £739,000 | £800,000 | £927,200 | £1,250,000 | |||||||||
“The above table shows at a glance the ships that have come between the Campania and the Lusitania. The Baltic shows the type of steamer that pays the best, going across at a moderate speed sufficient for most people while at the same time carrying an enormous amount of cargo.”[92]