Then followed a period of rivalry, the Cunard Company building the Gallia and Servia, the Inman Company the City of Rome, and the Guion Line the Alaska, all of which were completed in 1881, and afterward the Oregon for the Guion Line - 1883 - the Aurania the same year for the Cunard Company, and, later still, the America for the National Line, and the Umbria and Etruria for the Cunard Company in 1885.

Frames from outer edge of Tank to Upper Deck
Frames from outer edge of Tank to Upper Deck, 7 × 3½ × 8/16 for 250 ft. Amidships, for 60 ft. before and abaft these Points 6½ × 3½ × 6/16 at end of Vessel 5 × 3½ × 7/16, all spaced 24 in. apart and all carried to Upper Deck, double from Bilge to Bilge in way of Engines. - Frames in Tank on Lattice and Solid Floors, 5 × 3½ × 8/16, Intermediate Frames, 8 × 4 × 9/16 - Rev: Frames, 4½ × 3½ × 8/16, carried to Upper and Main Deck alternately double, 4½ × 4½ × 8/16 from Bilge to Bilge in E and B space.

Fig. 2 - SERVIA.

Since the completion of the Etruria, for various reasons there has been a pause in the tremendous strides made since 1879, and we may briefly review the results. Taking the Britannic as a standard with her ten years' average of 8¼ days across, and her quickest passage of 7 days 10 hours 53 seconds, we have now the following steamers of higher speeds. Taking them in the order of their absolutely fastest passage out or home, they stand thus:

TABLE I.

Days.Hours.Mins.
1Etruria.6531
2Umbria (sister ship).slightly longer.
3Oregon.61035
4America.61344
5City of Rome.6180
6Alaska.61837
7Servia.62355
8Aurania.711

It will thus be seen that from the 15 days' passage or thereabout, of the earliest Atlantic steamers, we had got down in the days of the Scotia to about 9 days; in the Britannic to 8¼ days, and, at the present time, we have got to 6¼ days, with seven ships afloat that have done the passage under seven days, and capable of making their average passages range between 6½ and 7¼ days.

Ranged in order of gross tonnage, these eight vessels stand as follows:

TABLE II.

1. City of Rome.8,144
2. Oregon.7,375
3. Aurania.7,269
4. Servia.7,212
5. Umbria.7,129
6. Etruria.7,100
7. Alaska.6,586
8. America.5,528

Here the America shows to advantage, for while being eighth in size she is fourth in point of speed, and from what the author can learn, although he had no authenticated details on the subject, he believed she is economical in coal consumption. He might perhaps be permitted to say that one of the most difficult subjects in connection with the propulsion of ships on which to get absolutely accurate data is that of coal consumption. The records of six to eight hours' trials for the purpose of ascertaining the coal consumption are absolutely worthless, as all shipbuilders and engineers know, and so far as English ships are concerned they are never attempted. Foreign owners frequently stipulate for such trials in their contracts with English shipbuilders, and get wonderfully economical results on paper, but the fact that the trials only extend over a few hours renders them valueless, however carefully the coal may be weighed during that period. An authentic record of the absolute quantity of coal consumed, say by each of the eight fastest Atlantic liners, together with their average indicated horse power on the voyage, for a series of voyages, would be extremely valuable.

He gave, in Table III., the consumption per indicated horse power per hour for a number of ships. This table affords valuable data, for it gives, in addition to the dimensions, the moulded draught of water, the midship area, the displacement, the indicated horse power, the speed on trial, the coefficients for the lines both from the block or parallelopipedon, and also from the midship section prism, together with the length and angle of entrance obtained by Kirk's rule, the Admiralty displacement coefficient, together with the coal consumption per day and per indicated horse power per hour.

Fig. 3   OREGON.
Fig. 3 - OREGON.

This table, as will be seen, contains some of the most important of the Atlantic liners, and also a number of other typical ships, which will add a variety to its interest and a value to it. The coefficient, which is contained in the thirteenth column of the table, viz.:

Dis 2/3 × speed³
- - - - - - - - - -
I.H.P. ×√(entrance.)
10

generally comes out for ships of similar type more nearly a constant in the true sense of the word than the corresponding Admiralty constant. As an example, we have the curves of resistance and horse power for the City of Rome and the Normandie, a large vessel of 6,000 tons, which the Barrow Company built for the Compagnie Generale Transatlantique, in which the coefficient of fineness and the form of the lines pretty closely resemble each other below water; and if we take from the curves the corresponding speeds and horse powers, and work out the constants by the two systems, we have at 14 knots the Admiralty constant for the City of Rome 322.2, and for the Normandie 304.8; and taking for a modified form of constant, the City of Rome gives 253.7 and the Normandie 251.9, which, as will be seen, are much closer together. Similarly, at 15 knots the Admiralty constant for the City of Rome is 310, and for the Normandie 295.2, while a modified constant comes out for the former at 245, and for the latter 244, again agreeing almost identically. The same at 16 knots, for the City of Rome the Admiralty constant comes out 297.6, and for the Normandie 282.8, while a modified constant comes out for the two ships 234.4 and 233.7 respectively, again showing marked agreement.

It may be mentioned that in these two ships the engines are of a similar type, being three-crank tandem engines, and the propellers have in both pitch and surface practically the same proportions to the power and speed. The value of these modified constants will probably be found to increase as the speeds increase up to the limit and beyond that point at which wave resistance becomes an important factor.

TABLE III.

NameLengthBreadthMoulded draughtMidship areaDist.Indicated H.P.SpeedBlock coefficientMidship section coefficientPrismatic midship section coefficient
D2/ × S3
I.H.P.
D2/ × S3
I.H.P. × √ent.
Kirk's systemCoal consumptionCylindersBoilersWorking Pressure
Length of entranceAnglePer dayPer I.H.P.DiameterStrokeHeating surfaceBar surface
ft. in.ft. in.ft. in. Ins.Ins. Lbs.
City of Rome542 652 021 5½103111,23011,89018.235.649.925.702255201.3161.278° 29'1852.2{3 @ 46 }
{3 @ 86 }
7229,286139890
Normandie459 449 1119 9¾8927,9756,95916.66.614.901.681265219.5146.418° 44'1482{3 @ 35 7/16}
{3 @ 74 7/8}
6721,40475685.2
Furnessia445 044 622 2½8938,5784,0451 14.682.903.755284273108.710° 28'972.249-1006610,39644090
Arizona450 045 1½18 97586,4156,30017.589.895.658269.2217153.797° 30' - - {1 @ 62 }
{2 @ 90 }
66 - - 90
Orient445 046 021 4½9047,7705,43315.538.621.919.676270.8225144.178° 21' - - {1 @ 60 }
{2 @ 85 }
60 - - 75
Stirling Castle420 050 022 39907,6008,39618.4.569.889.639286.8233.7151.38° 22' - - {1 @ 62 }
{2 @ 90 }
6621,161787100
Elbe420 044 920 08076,3505,66516.571.591.901.655275.5229144.67° 56' - - {1 @ 60 }
{2 @ 85 }
60 - - -
Pembroke Castle400 042 017 06485,1302,435.813.25.623.623.692284258122.98° 49'441.743 and 86577,89628899
Umbria and Etruria500 057 022 610909,86014,32120.18.538.896.637260191.81846° 52'3152.1{1 @ 71 }
{2 @ 105 }
7238,8171606110
Aurania470 057 020 010208,8008,5001 17.5.575.942.632266204.61708° 38'2152.2{1 @ 68 }
{2 @ 91 }
7223,2841001 -
America441 851 3 - - 6,500 - 1 17.8 - - - - - - - 185 - {1 @ 63 }
{2 @ 91 }
66 - 882 -
Oregon501 054 223 8115011,00013,30018.3.599.849.67227.9190164.39° 39'3102.2{1 @ 70 }
{2 @ 104 }
7238,0471428110
Servia515 052 023 3½104610,96010,3001 16.9.610.862.71231192145.310° 42'2052{1 @ 72 }
{2 @ 100 }
7827,4831014 -
Scotia, P.S.369 047 619 98676,0004,6321 14.31.605.92.65208.9186126.813° 21'1683.4 - - - -
Alaska500 050 021 09499,210 - - .614.904.679 - - 160.238° 2' - - {1 @ 68 }
{2 @ 100 }
72 - - 100
Aller438 048 021 09077,4477,97417.9.590.899.656277225150.68° 10' - - {1 @ 44 }
{1 @ 70}
{1 @ 100 }
7222,630799150
Ems430 046 1020 7½8777,0307,25117.55.593.907.652273223149.48° 40' - - {1 @ 62 }
{2 @ 86 }
6019,700780100

1 Mean speed of a voyage across the Atlantic Ocean.

The author next considered the strains to which a ship is exposed, and stated that he had before him the calculations for three of the largest vessels, two of them of iron and the other of steel; and he found, in the case of the iron, the maximum tension on the gunwale during the greatest hogging strains likely to be endured at sea would not exceed about six tons per square inch, while in the case of the steel ship it is only about 6½ tons. These strains are well within the limits of safety, and a comparison of the scantlings of these with the others justifies the assertion as to their general safety from a structural point of view. The sections of these three ships are shown in Figs. 1, 2, and 3, with their principal scantlings. It will be seen from these sections that the three ships differ materially in their mode of construction. In the case of Fig. 1, which represents the City of Rome, the largest of the three, it will be seen that the main framing of the vessel is entirely transverse, with very heavy keelsons in the bottom, and large partial bulkheads or web frames, and the outside plating arranged on what is termed the edge to edge principle, with a great portion of it double.