The following auxiliaries were in use on all the trials:

Main circulating pump.

One main feed pump.

One fuel oil service pump.

One fuel oil heater.

Forced draft blower.

Fuel oil transfer pump.

Auxiliary feed pump.

(In connection with the measure

ment of oil and water.)

Auxiliary air and circulating pump (on 2-hour full-power

and 2-hour reduced power runs only).

Steering engine.

Galley.

One dynamo.

Ice machine.

NOTES.

PARTS OF VESSEL TO WHICH APPLICATION OF ELECTRIC WELDING HAS BEEN CONSIDERED AND APPROVED BY AMERICAN BUREAU OF SHIPPING AND LLOYDS.

Although the classification societies are proceeding very cautiously in approving the application of electric welding to new ship construction, because of the lack of a reliable system of testing the quality and strength of the welds, nevertheless both the American Bureau of Shipping and Lloyds now approve the welding by electricity of the following parts of steel vessels:

Deck rail stanchions to plating.

Clips for detachable rail stanchions.

Continuous railing rods (joints).

Attaching deck collars (L rings) around ventilators.
Attaching deck collars (L rings) around smoke stack.

Attaching cape rings around smoke stack, pipes, etc.

Attaching galley fixtures to plating.

Attaching bath and other fixtures in officers' quarters.
Attaching cowl supporting rings to ventilators.
Bulwark rail top splicing and end fitting.

Skylights over galley.

(a) Engine room stairs and gratings.

(b) Boiler room stairs and gratings.

Attaching (a) and (b) to plating grab rods on casing.

All stairs and ladders, including rail attachments.

Door frames to casing, hinges, catch holds, coachhooks, etc.

Clips for attaching interior wood finish to casing.

Entire screen bulkhead.

Coal chutes.

Butts of watertight and oiltight boundary bars on bulkheads or floors in double bottom.

Ventilator cowls.

Stacks and uptakes.

Bulkheads (that are not structural parts of the ship), partition bulkheads in accommodation.

Framing and supports for engine and boiler room flooring or gratings. Cargo batten cleats.

Tanks (that are not structural parts).

Shaft alley escapes.

Steel skylights over accommodation spaces.

Engine room skylights.

Grab rods on exterior and interior of deck houses.

Deck houses not covering unprotected openings through weather decks. Reinforcing and protecting angles around manholes.

Joints of watertight angle collars at frames in way of watertight flats."International Marine Engineering."

THE EVOLUTION OF THE DESTROYER.

REMARKABLE DEVELOPMENT OF PRESENT-DAY DESTROYER FROM EARLY TYPE TORPEDO BOAT-RAPID ADVANCES IN BOILER AND TURBINE CONSTRUCTION.

BY COMMANDER S. M. ROBINSON, U. S. N.

Progress in marine engineering has been very rapid during the past thirty years, but it is believed that the development of the torpedo boat has been more rapid than that of any other type of vessel. Undoubtedly the main reason for this rapid progress is that it takes a very short time, comparatively, to build a destroyer, so that the engineer can test his ideas and make several advances in the time required to build one battleship. It is certainly a far cry from the 22.5-knot Cushing to the 36.88-knot Dent. The Cushing was our first torpedo boat and the Dent is one of our latest destroyers. The following table and accompanying photographs give a comparison between the two boats:

The Cushing was our first torpedo boat and was designed and built in 1890 by Nathaniel Herreshoff at the Herreshoff Works, Bristol, R. I. Inasmuch as she represents our maiden effort in this line of marine engineering, a brief description of her machinery may be of interest.

MACHINERY OF THE "CUSHING."

She was equipped with twin screws, each driven by a five-cylinder, quadruple expansion engine. The cylinders were 112, 16, 222, 221⁄2 and 221⁄2 inches in diameter, respectively. The stroke was 15 inches. The engine supports were a distinct advance in engineering for that day and consisted of 11⁄2-inch steel rods, braced diagonally, and forming the cap bolts of the main bearings; the latter were secured to a bed-plate consisting of a single sheet of 3/4-inch wrought iron with openings cut for the cranks. The bed-plate was secured in a fore-and-aft direction to keelsons and was also supported under the main bearings of the high-pressure and after lowpressure cylinders, the other main bearings being entirely without support; but, owing to the extreme care taken in balancing, the engines ran without vibration.

The boat was equipped with two Thornycroft boilers each having 38.3 square feet of grate surface and 2,375 square feet of heating surface. The boilers also represented an advance in engineering, as the longitudinal seams in the drums were welded instead of riveted. The boilers were designed for a pressure of 250 pounds per square inch.

For some time after the trials of the Cushing, the advance in torpedo boat engineering was limited by the progress in the design of propellers and the art of balancing engines. Like many other points of engineering, the screw propeller was not as well understood at that time as it is today, and many failures on trials were recorded due solely to improper propeller design. Also the higher speed of ship desired required higher engine speeds than had been the custom, with the result that vibration was so bad in many cases as to make it impossible to run at full power. However, both of these problems were successfully solved and the art of engine balancing, in particular, was carried to a high degree of success. This line of development reached its climax with the Stewart class, which were built in 1902.

THE LAST OF THE RECIPROCATING ENGINE BOATS.

The following table gives the general characteristics of these boats:

These were the last of the reciprocating engine boats. We see that the speed has increased from 22.5 knots to 29.3 knots, the boiler pressure from 250 to 300 pounds, the indicated horsepower from 1,720 to 8,000, and the high-pressure cylinder from 111⁄2 inches to 23 inches diameter. There is no doubt but what with the present-day methods of lubrication and other improvements of design, such as superheat, etc., destroyers of higher speeds could be built using reciprocating engines, but the improvement would not be great and the destroyer had just about reached its limitation as to speed.

Up to this time torpedo boats and destroyers had been regarded as coast and harbor defense vessels and long-distance cruising had not been carried out by them. The ordinary method of operation was to make short runs at high speed from a base, but in 1904 two of these boats, the Preble and Paul Jones, were sent to Panama to act as despatch vessels, and later in the year a flotilla of destroyers was sent from the Atlantic coast to the Asiatic station, via the Mediterranean. Both cruises proved conclusively that the destroyer was a reliable sea-going vessel and had a cruising radius that compared favorably with other types of ships. The fuel economy at low speeds was the greatest surprise of all. At that time so little was known regarding the fuel consumption at cruising speeds that