Footnotes.

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1 Report of Lecture in the Liverpool Albion, delivered in Liverpool, December, 1835.

2 The account given of the Savannah is condensed from Admiral Preble’s Notes for a History of Steam Navigation.

3 Daniel Dod, an American citizen, was granted a patent November 29, 1811, in which he states: “I form the condenser of a pipe or number of pipes condensed together; and condense the steam by immersing the pipes in cold water, either with or without an injection of water.”

The present surface condenser consists essentially of a great number of small brass tubes, about three-fourths of an inch in diameter, passing through an air-tight chamber. The exhaust steam from the cylinders enters the chambers, and cold water is constantly pumped through the tubes. The steam is condensed by contact with the cold tubes, and the water thus obtained pumped back to the boiler in a fresh state, instead of being mixed with about thirty times its weight of salt water, as in the old jet condenser. Practice varies, the steam sometimes being passed through the tubes and the water around them.

4 The Naval Chronicle of 1818, vol. xxxix., p. 277, speaking of the steamers on the Clyde, says: “No serious accident has occurred since their introduction, which is more than two years. The secret of security consists in using large steam-engines of great power and small pressure. If the boilers of cast-iron should in any part give way, a piece of cloth is firmly wedged in the hole, and the vessel proceeds without any danger or inconvenience to the passengers.”

5 Compiled from official data in Engineering, June 19 and July 10, 1891.

6 A fuller discussion of this subject is given in the chapter on “Safety on the Atlantic.”

7 This is as shown by Lloyd’s Register, 1891-92; the official returns, dealing with the official year, give 609 vessels and 537,605 net tons; our own net tonnage is about 74 per cent, of the gross shown.

8 The figures for these three ports are exclusive of the tonnage built on foreign account.

9 I use here the opinion, expressed to the writer, by a great English steel manufacturer, whose establishment stands at the head of the industry abroad.

10 This, however, is not an absolute test of the fineness of the water-lines of a vessel, and it can only be used as such on the assumption that the midship sections of ships are of similar form. The best test of the fineness of water-lines is made by taking the displacement as a percentage of the prism whose length is that of the ship and whose section is the same as the midship section of a ship, assuming, however, that the midship section of all ships is approximately that found in general practice to-day; in speaking of coefficients it will mean the percentage of the rectangular block above named.

11 More than thirty years ago this matter had been observed by the officers of the British navy, and experiments were ordered to be tried with H. B. M. S. Flying Fish, a 1,100-ton cruiser, her length being 200 feet, breadth 30 feet 4 inches, and her draft of water 10 feet 6 inches forward and 13 feet aft. With 1,290 I. H.-P. her speed was only 11.64 knots, whereas with 577 I. H.-P. it was 9.923 knots, and a speed of 11.201 was obtained with but 878 I. H.-P. A false bow 18 feet long was then fitted, so as to give finer lines forward, or, as sailors describe it, “a better entrance,” when it was found that with 1,285 I. H.-P. a speed of 121/2 knots was attained, and with 1,345 very nearly 123/4 knots. There is also every reason to suppose that could the stern have been altered in a similar way, the speed would have been still higher, in spite of the ship being larger and with a consequent increase of immersed surface to cause resistance. It has, besides, been observed on many occasions that when steamers have been cut in two and lengthened there has been no diminution of the speed, but, on the contrary, in some cases there has actually been a gain; so that in these two instances there is an apparent anomaly, viz., that with the same power the larger ship is propelled at a quicker speed.

The late Dr. Froude investigated this matter some years ago, and showed that such results were quite possible, independently of any fining of the lines, owing to the effect on the ship of the waves set up when in motion. One very curious illustration of how such waves may seriously affect a vessel is in that of a yacht built many years ago by an eminent firm on the Clyde, which failed to come anywhere near the performances guaranteed owing to the fact that as the speed increased the hollow following the wave formed at the bow increased and approached nearer and nearer to the paddle-wheels, until the water dropped below the floats and allowed the wheels to spin in the air; the propelling effect was thus entirely lost until the vessel slowed down sufficiently for the water to rise again to the level of the paddle-wheels. Such a thing could scarcely happen with a screw steamer; but the very bad steering qualities of certain naval ships is due to the fact that the inrush of water at the stern causes currents to flow with the ship, and therefore to produce quite different results with the rudder from those which generally obtain.

12 A nautical mile is 6,080 feet, the land mile being 5,280 feet. The knot is a measure of rate of speed per hour. A vessel makes 20 knots when she is travelling at the rate of 20 nautical miles per hour.

13 The dimensions, speed, etc., of the steamers here referred to, as well as other representative steamers from 1836 to 1890, are shown in the table on page 78.

14 In the case of river steamers of moderate size there is not the same restriction on the position of the wheel, and as a matter of fact, as in the case of stern-wheelers, it is altogether at one end.

15 It is now claimed for the twin-screw ship that she is not only capable of entering shallower harbors, but that she is in every way much safer, and it is most unfortunate that, owing to an act of carelessness, this was not conclusively shown in the recent accident to the City of Paris. But there is safety in the twin-screw beyond that which is rendered possible, as in the cases of the City of Paris and Majestic, by the division of the engine-rooms, viz., the fact that if one engine breaks down it is improbable that the other would do so at the same time, and that the vessel, although somewhat crippled in speed, would still be able to pursue her voyage; also, that in the event of accident to the steering apparatus the passage could be continued and the direction of the ship guided by regulating with one or both of the engines. Each of these features is pronounced, and the advantages have been proved on many occasions.

16 See the chapter on The Development of the Ocean Steamship.

17 Through the courtesy of Mr. George W. Esslinger, assistant to Captain John E. Moore, landing agent.

18 There are several other lines, like the Liverpool, Brazil & River Plate, and John Norton’s Son, which usually send out from four steamships a year to one a month, but which are doing very little just now, owing to the disorganized condition of trade in the River Plate region. Reciprocity with Brazil is counted upon to increase their trade.

There is one line of steamships from New York direct to Indian, Chinese, and Japanese ports by way of the Mediterranean Sea and the Suez Canal. It is operated by Edward Perry & Co., and case oil forms the bulk of the trade. About one vessel a month is sent out, and this vessel has a tonnage of about 3,000 gross.

Carter, Hawley & Co., and Carter, Macy & Co., had during the year 1891 about 25 steamships consigned to them from China and Japan, the tonnage of which was about 60,000 gross. Inward these vessels are tea-laden, but on the return trip they are usually chartered by other firms for general cargo.

19 Certain kinds of freight admit of peculiar packing, of which an instance occurs to me in the loading of American cheeses. The side-ports of the ship are opened, and a series of inclined chutes are arranged so that the cheeses roll by their own weight from the truck on the pier through the open port, and are switched off on side chutes, which carry them to their final resting place, where men stow them in solid layers. Some vessels, not provided with side-ports, hoist the packages on deck in nets and lower them down the hatchways. Some of these products of the American dairy return to us as English manufacture—the “Cheshire” and “Double Gloucester.”

20 The table is from Lloyd’s Register, 1890-91.


                                                                                                                                                                                                                                                                                                           

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