Ocean Steamships / A popular account of their construction, development, management and appliances - French Ensor Chadwick; John H. Gould; Ridgely Hunt; J. D. Jerrold Kelley; William H. Rideing; A. E. Seaton

Name of Ship.	Paddle or screw.	When Built.	Length on Water- line.		Breadth.		Draft.		Horse- power.	Tonnage.
			Ft.	Ins.	Ft.	Ins.	Ft.	Ins.	Nominal.
Sirius	Paddle	1836	170	0					270	700
British Queen	„	1839	234	0	40	4	16	0	500	2,016
Liverpool	„	1839	210	0	36	0			404	1,150
Great Western	„	1838	212	0	35	4	16	0	450	1,340
Britannia	„	1840	206	0	34	6			450	1,155
Scotia	„	1862	366	0	47	9	22	0	1,000	2,358
City of Richmond	Screw.	1873	440	0	43	6			700	4,780
City of Berlin	„	1874	488	6	44	2			1,000	5,526
									Indicated
Germanic	„	1874	455	0	45	2	23	7	5,400	5,008
Britannic	„	1874	455	0	45	2	23	7	5,400	5,004
Arizona	„	1879	450	0	45	1	18	9	6,300	5,164
Servia	„	1881	515	0	52	0	23	3¹⁄₂	10,300	7,392
City of Rome	„	1881	542	6	52	0	21	5¹⁄₂	11,890	8,144
Alaska	„	1881	500	0	50	0	21	0	10,000	6,932
America	„	1883	432	0	51	0	26	7	7,354	5,528
Oregon	„	1883	501	0	54	2	23	8	13,300	7,375
Umbria	„	1884	500	0	57	2			14,320	8,128
Etruria	„	1884	500	0	57	2			14,320	8,120
City of New York	„	1888	527	0	63	0			18,400	10,500
City of Paris	„	1888	527	0	63	0			20,100	10,500
Majestic	„	1889	565	0	57	6	26	0	17,000	9,861
Teutonic	„	1889	565	0	57	6	26	0	17,000	9,686

Name of Ship.	Trial Speed.	Cylinders.		Working Pressure.	Time occupied on Quickest Passage.
Name of Ship.	Trial Speed.	Diameter in Inches.	Stroke in Inches.	Working Pressure.	Time occupied on Quickest Passage.
	Knots.			Lbs.	D.	H.	M.
Sirius					18	11	15
British Queen	8.5	Two 77¹⁄₂	84		13	18	10
Liverpool		Two 75	84		11	18	5
Great Western		Two 73	84		10	10	15
Britannia		Two 72	82
Scotia	13.9	Two 100	144		8	4	30
City of Richmond		68 and 120	60		7	18	50
City of Berlin		41, 65, and 101	66		7	14	12

Germanic	16.0	Two 48 and two 83	60	70	7	11	37
Britannic	16.0	Two 48 and two 83	60	70	7	10	53
Arizona	17.0	One 62 and two 90	66	90	7	3	30
Servia	16.9	One 72 and two 100	78		6	23	50
City of Rome	18.23	Three 46 and three 86	72	90	6	21	4
Alaska	18.0	One 68 and two 100	72	100	6	18	37
America	17.8	One 63 and two 91	66		6	14	18
Oregon	18.3	One 70 and two 104	72	110	6	9	51
Umbria	19.0	One 71 and two 105	72	110	6	3	4
Etruria	19.5	One 71 and two 105	72	110	6	1	50
City of New York	20.13	Two sets 45, 71, and 113	60	150	5	21	19
City of Paris	21.952	Two sets 45, 71, and 113	60	150	5	19	18
Majestic	19.87	Two sets 43, 68, and 110	60	180	5	18	8
Teutonic	21.0	Two sets 43, 68, and 110	60	180	5	16	30

It may well be asked how what seemed to be an impossibility in 1876 has been achieved so successfully in 1890, and it is perhaps less interesting to note the changed conditions than the causes that have produced them. In the very early days of steam navigation the engines were substantially those used for pumping and other purposes on land. Had the genius of Trevithick exerted itself in the direction of improvements in ship propulsion as much as it did in abortive efforts to make the locomotive a success, there is no doubt we should have had fast passenger steamers before we had railway trains; and had not the prejudice of Watt hung over the engineering world as a cloud which obscured the clear light of science, some other engineer would have accomplished the same result. It is disappointing to find that a man of Watt’s genius and reputation should have attempted to damp the ardor of men like Symington and Miller by predicting failure for an engine when applied to marine propulsion, and by threatening the pains and penalties of the law for infringement of patent should those enterprising geniuses disprove his predictions. There can be no doubt that the statement from a man of his position, that Trevithick and others who were experimenting, as well as working, with steam of high pressure deserved hanging for their diabolical inventions, would have great effect on the engineering world, then in its infancy; and the few accidents that in later years occurred on steamboats, through the crass ignorance or the reckless negligence of those placed in charge, recalled to the mind of another generation the words of Watt, and made them doubly impressive as well as deterrent to further progress. Even in our own days the use of steam at such pressures as have enabled the present wonderful monuments of mechanical skill to be commercial successes has been animadverted upon, and prophesied about, and openly denounced, and it is only those who are engaged in this pioneer warfare who know how depressing and discouraging such language is, or who appreciate the great responsibility taken in advancing into the unknown—that is, unknown to the world at large. Moreover, the body of every nation is more or less conservative and slow to comprehend, much less to appreciate, new inventions or new forms of old inventions. Hence, no doubt, it was that an enterprising company like that presided over by Sir Samuel Cunard should refrain from building its ships of the superior material, iron, and adhere to the inferior propeller, the paddle.

The Inman Line Steamer City of Paris.

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The paddle-wheel was obviously the first instrument accepted by the early engineers as a means of propulsion. Long after the experiment of H. B. M. S. Rattler had demonstrated the contrary, the public faith in the visible wheel was greater in reality and more sincere than that in the invisible screw; and it is probable that it was more the question of cost than anything else that gained the victory for the screw for ocean and general service. The paddle engine is in itself heavier and occupies more room than the screw engine; it is as a rule more expensive per I. H.-P.; and in wear and tear—especially of the propeller itself—it far exceeds the screw. It occupies the best part of the ship, and its position is not a matter of choice, as with the screw engine, but is, of necessity, at or near the middle of the ship.[14] It is evident that a paddle steamer must require more room, and that in moving among ships or other obstructions the liability to damage the propeller is greater than with the screw steamer, and in the case of a long voyage the paddle generally worked at a disadvantage, as at the commencement it was too deeply immersed, and at the end not immersed enough for efficient working. If the sails were set so as to steady the vessel, or if set in sufficient quantity to be of any use in quickening the speed, she was inclined until the lee wheel was “buried” and the “weather” wheel doing very little work; besides there was a general tendency on the part of the ship to turn round, which had to be counterbalanced by the rudder. The race of water from the wheels past the ship being at a high velocity, and raised above the normal level, causes a resistance to the ship beyond that due to her passage through the water, as in the case of a screw ship. On the other hand, the paddle boat is more readily got into motion and her speed more rapidly arrested than is the case with the screw steamer; and it is claimed for the paddle-wheel—although the foundation for such a claim is rather nebulous—that when the engines are working at full speed the ship is prevented from the excessive rolling observable with a screw vessel. But against this it must not be forgotten that the paddle engine is far more trying to the structure of the ship, on account of the great weight of the wheels being taken on the sides of the hull, as well as from the effort of the wheels in propelling being applied at the same place. Then there is the additional danger, and that not a remote one, that in case of the shaft breaking and a wheel falling clear of the ship, she would upset. An accident of this kind has occurred more than once, but there is no record of the actual result being so calamitous as just stated, owing to other fortuitous circumstances. That which retains the paddle-wheel in favor to-day, and renders it a necessity in spite of argument or prejudice, is the fact that the screw requires that the draft of the ship shall not be less than its own diameter, whereas in the largest paddle boats a dip of wheel of six feet is generally sufficient. Hence it is that nearly all fast steamers plying on rivers or shallow estuaries, and channel steamers running to ports where there is little water when the tide is low, are of necessity paddle-wheel. By employing two screws (one on each side instead of one amidships) the draft of water can be reduced by at least thirty per cent. Likewise, by increasing the number of revolutions smaller screws will do, and the draft of water may be still less, so that some thirty years ago, on the introduction of twin-screws, there were soon many ships built for services that had hitherto been monopolized by paddle boats;[15] and to-day, when there is a demand for higher speed and more power, and where paddle-wheels are not admissible, three screws are being employed. Ships have also been employed with four screws, viz., two at the bow and two at the stern, and, for the purpose for which they were required, answered very well indeed; but the worst possible place for a propeller is obviously at the bow, and therefore in these ships the bow screws were not very efficient, but they undoubtedly added somewhat to the power of the ship. In the same way some tug-boats have been fitted with a screw at each end.

All attempts at propulsion with internal propellers—that is, by turbine wheels, pulsometers, ejectors, or by pumps—have failed in consequence of the great friction set up by the water in its rapid passage through the pipes from and to the sea; the motion must be rapid owing to the size of the pipes being necessarily restricted. The best experiment with this kind of propeller was made on a costly scale by the British Admiralty in 1866, when they fitted the iron-clad gun-boat Waterwitch, of 1,200 tons displacement, with a Ruthven’s hydraulic propeller, consisting of a horizontal turbine wheel drawing its water through the bottom of the ship and discharging it fore-and-aft-ways at each side, and driven by an engine of 160 nominal horse-power; and although this vessel was only 162 feet long, 32 feet broad, and drew 11 feet 4 inches of water, her speed was only a little over 9 knots, with an indicated horse-power of 801. The speed co-efficients whereby her performances could be compared with that of other ships were most disappointing.

The Twin Screws of the City of New York