Scientific American Supplement, No. 799, April 25, 1891

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April 25, 1891, by Various

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Title: Scientific American Supplement, No. 799, April 25, 1891

Author: Various

Release Date: March 22, 2004 [EBook #11649]

Language: English

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SCIENTIFIC AMERICAN SUPPLEMENT NO. 799

NEW YORK, APRIL 25, 1891

Scientific American Supplement. Vol. XXXI, No. 799.

Scientific American established 1845

Scientific American Supplement, $5 a year.

Scientific American and Supplement, $7 a year.

THE NEW GERMAN DISPATCH BOAT METEOR.

In time of war the dispatch boats are the eyes of the fleet. It is their duty to reconnoiter and ascertain the strength of the enemy and to carry the orders of the commander. For this service great speed is of the utmost importance. As all nations have increased the speed of their war ships during the last few years, it has become necessary to build faster dispatch boats. Although our new vessels of this class, Blitz, Pfeil, Greif, Jagd, and Wacht, fulfill the requirements, still greater speed was deemed requisite, and steps were taken for the construction of the Meteor, which was launched at Kiel in 1890. This vessel is 262 ft. long, 31 ft. wide, and has a draught of 13 ft., and a displacement of 950 tons. There are two independent engines, each of which develops 2,500 h.p., making a total of 5,000 h.p.; and each engine drives a screw. When both engines are running with their full power, the Meteor has a speed of 24 knots (over 27½ miles) an hour, which is equal to the speed of a freight train.[1] As the resistance of the water increases greatly with an increase in the speed of the vessel, the engines of the Meteor are very large in comparison with the size of the vessel. The largest armored vessel in the navy, the Konig Wilhelm, for example, has a displacement of 9,557 tons, and its engines develop 8,000 h.p., driving the vessel at a rate of 14 knots an hour; that is, 0.84 h.p. to each ton of displacement, while in the Meteor there is 5.26 h.p. to each ton of displacement. The Meteor has a crew of 90 men, and an armament of eight light guns, and has no rigging; only one mast for signaling. Steam power is used for raising the anchor, removing the ashes from the engine room, and for distilling water. The vessel is lighted with electricity, and is also provided with electrical apparatus for search lights.—Illustrirte Zeitung.

THE NEW GERMAN DISPATCH BOAT METEOR.

[1]

This, we believe, is the fastest vessel of the kind afloat.—ED. S.A.

THE RAISING OF THE ULUNDA.

Shortly after the recovery of the Ulunda, below described, the North American and West Indian squadron of the Royal Navy visited Halifax, Nova Scotia. The simple and novel means adopted for raising the ship attracted considerable attention among the officers of the fleet, and by way of stimulating the studies of the junior officers in this branch of their duties, a prize was offered for the best essay on the subject, to be competed for by the midshipmen of the various ships. The essays were adjudicated upon by Captain W.G. Stopford, of the flag ship—H.M.S. Bellerophon—and the first prize was awarded to the following paper, written by Mr. A. Gordon Smith, of H.M.S. Canada. The article needs no apology, but it is only just, says the Engineer, to mention the fact that the writer is not yet eighteen years of age.

The steamship Ulunda, on the remarkable raising and recovery of which this paper is written, is an iron screw ship of 1,161 tons, until lately belonging to the Furness line. It is a sister ship to the Damara, of the same company, and was built and engined by Alex. Stephens, shipbuilder and engineer, at Glasgow, being fitted with compound vertical engines, of 200 nominal horse power, having two cylinders of 33 inches and 66 inches diameter respectively, which are capable of sixty-five revolutions per minute, and give a speed of twelve knots an hour.

For supplying steam to the engines there are two return-tube boilers, each having three furnaces, and there is also a donkey boiler, which is used in harbor for working the four steam winches on deck.

She is divided into seven watertight compartments by athwartship bulkheads. The foremost one is the usual collision bulkhead. Between this and the foremost engine room bulkhead are Nos. 1 and 2 holds, separated by a watertight bulkhead. Abaft the after engine room are two more holds, divided in the same manner as the forward ones, and astern is another compartment, in which all stores are kept. Coal bunkers form a protection for the engines and boilers. Fore and aft the ship, as low down as possible, are a number of ballast tanks, which can be filled with or emptied of water as occasion requires to alter the trim of the ship. Extending over all holds there is a strong iron lower deck, about 8 feet below the upper deck, which is pierced with a hatch over each hold immediately under a corresponding hatch in the upper deck, for stowing and unstowing cargo.

In the engine room there are six steam pumps, two of them bilge pumps, worked by the main crossheads, for clearing the engine room of water. For pumping out the ballast tanks there are two more, which have their own independent engines. The remaining two are for various purposes. Besides these there are several hand pumps on the upper deck.

Having been built in 1885, the Ulunda is almost a new ship, and has been used principally as a cargo steamer, though she is provided also with a saloon and staterooms for a few passengers. She was on her way from St. John, New Brunswick, to Halifax, when during a thick fog she struck on Cowl Ledge, a reef between Bryer and Long Islands, on the southwest coast of Nova Scotia, about half a mile from the shore. The cause of the disaster was probably one of the strong tide eddies which exist in the Bay of Fundy, and which had set her in toward the shore. It was calm at the time, and she was making seven knots an hour; and, being close to the shore, leads should have been going in the chains. Had this precaution been taken, very probably she would have been able to stop or anchor in time to avert this catastrophe. There was no cargo on board, it being intended to ship one at Halifax for London.

When ashore on this reef she was sold by public auction at Halifax, and fell to a syndicate of private individuals for £440. These gentlemen at once decided to raise her if possible, transport her into dock, and repair her. They commissioned Captain Kelly, of the Princess Beatrice, a ship then in harbor, to visit her and see what could be done for that purpose. He went with a hired crew to Annapolis, and from thence proceeded to the steamer by means of a tug, a distance of about forty miles. When they arrived they found the Ulunda with her head to sea, and her stern in only 2 ft. of water at low tide, with a list of 30 deg. to port and her foremast broken short off. At high tide the water flowed over the upper deck. On examination, the engine room was found full of water, which did not rise and fall with the tide, showing that it had been filled at high tide through its skylight. No. 3 hold was also full, but had a slight leak, which was shown by the water falling slowly at low tide and rising in the same manner at high water. The other three holds were hopelessly leaky.

Upon investigation, it was decided to pump out the engine room compartment and No. 3 hold, and to make the iron lower deck watertight over the remaining holds. For this purpose three powerful pumps, with the necessary boilers, were obtained from Halifax, sent by rail to Annapolis, and then shipped on board a tug, from which they were hoisted into the Ulunda by means of the derricks on the mainmast. These were centrifugal pumps, capable of discharging 2,000 gallons a minute each. One was placed in the engine room, another with its suction in No. 3 hold, and when these two compartments were pumped dry, it was found that in No. 3 hold the leak was easily kept under, while in the engine room there was no leak at all. The third pump was not used.

In the two foremost holds 2,000 large casks were then placed, and all the hatches over the leaky holds—Nos. 1, 2, and 4—were battened down, and made airtight