She was named the Alarm and it was hoped that she would be as fearsome as her name implied.
Described variously as a “torpedo boat,” a “torpedo ram,” and an “iron ram gun boat,” the vessel was designed by Admiral David Dixon Porter of Civil War fame. She was built in the mid-1870s at the New York Navy Yard, the first iron vessel ever built there. The Alarm was the result of a search for a more effective means of employing two devices used during the Civil War, the ram and the spar torpedo. Admittedly an experiment, and not too successful an experiment at that, the vessel is interesting enough to merit a review.
At this time the ram, however ineffective it might have been in actual combat, was enjoying a brief season of popularity. The extensive use of torpedoes, particularly by the Confederate Navy, was noted with considerable professional interest both here and abroad. Impetus was given, during the last half of the 19th century, to research which would lead to the idea of the torpedo as we know it today. For a time, however, developments centered largely around refinements of the spar torpedo and the design of vessels for the purpose of utilizing it more effectively as an offensive weapon. Of such background was the Alarm born.
The vessel was 173 feet over-all, including a big, plough-shaped ram 32 feet long. She had a beam of 28 feet, a draft of 11 feet, and a displacement of about 800 tons. Her complement consisted of five officers and 35 men. In many ways the Alarm was an advanced ship for her time. She was built of iron on the transverse bracket system with compartmented double bottom and with the hull divided by watertight bulkheads every 25 feet. There were provisions for flooding the double bottom to decrease her freeboard.
Although advanced in some respects, the Alarm proved to be deficient in others, due largely to her experimental nature, as well as to the fact that, while she was building, she was outdated by the fast-moving technical developments of the day.
Since the vessel was designed to fight bow on at all times, the bow alone was armored. A single big gun, a 15-inch smoothbore, was mounted in a fixed position on the bow. This required maneuvering the vessel herself in order to train the gun. Four Gatling guns were mounted along the rails. The smokestack was telescopic, and a small, low “musket- proof” pilothouse was located aft. It was assumed that it would be less vulnerable there, although the resultant handicap to the helmsman in such an awkward location can be imagined. With her big ram and her tall smokestack, with her pilothouse located aft, and without a mast of any description, the Alarm was an odd-looking craft, to say the least.
Offensive weapons included three torpedoes, these fitted to spars, one extending forward from the bow and one extending out on each beam. The bow spar was 30 feet long; the beam spars were each 17 feet long. All were below the waterline and were unique in that they could be withdrawn at will into the hull by small auxiliary engines and winches. The ram doubled as a casing for the bow torpedo, being cut off from the vessel proper by a watertight compartment.
The spars were hollow steel tubes sliding in and out of the hull so that torpedoes could be fitted to the ends. The port through which the spar projected was provided with a water- box with double doors and heavy rubber washers which gripped the spar tightly as it ran in and out. The end of the spar entered the rear of the torpedo for a distance of about a foot. The bow torpedo was a cylinder 4½ feet long and one foot in diameter, with a conical head. The beam torpedoes were of the same shape but were slightly smaller. All torpedoes were detonated by electricity.
Another feature of the Alarm was that she had no rudder. In lieu of a screw, she was fitted with a Fowler wheel which was used for steering as well as for propulsion. Simply described, the Fowler wheel was a feathering paddle wheel turning horizontally instead of vertically. Only one of the four paddles at a time was actually propelling. The others were in a feathered position, presenting only their edges. This feathering motion was controlled by an eccentric cam. By this action the stern of the vessel could be twisted around as though on a pivot. The cam was activated by a small auxiliary engine under the control of the helmsman. By means of a hand lever, steam was admitted into the engine; then, by turning a horizontal hand wheel in either direction, the helmsman controlled the movement of the cam as desired. Above the wheel was a dial which indicated the position of the paddles so that the helmsman could feather them at any point.
The Fowler wheel gave excellent maneuverability, but any advantage thus gained was offset by the comparatively slow speed of the wheel. Eleven knots was the best the Alarm could do, whereas a minimum of at least 18 knots was desirable.
After a series of trials, the Fowler wheel was replaced by another experimental device, the Mallory steering propeller. This was a six-bladed screw, arranged in such a manner that it could be revolved around a central axis to steer the vessel as well as propel her. As was the case with the Fowler wheel, the Mallory propeller gave the Alarm excellent maneuverability, but it failed to give her the desired speed.
Considerable controversy then developed around the Alarm. Critics, both in and out of the service, criticized the large sums of money spent on the vessel. They insisted that she was a thoroughgoing failure, pointing out, among other things, her slow speed. Champions of the vessel countered by saying that the extreme maneuverability of the Alarm more than compensated for her slowness. They indicated that the Alarm was designed to fight bow on and that maneuverability, not speed, was required. The critics replied that it was impossible for any vessel always to fight bow on, that with her slow speed she could never bring her torpedoes into action, and that her single fixed gun was a feature that made her especially vulnerable.
The controversy waxed hot in the public press and in professional journals. This was brought to an end before very long, however. Within a comparatively short time, the breech-loading rifle and the self-propelled and self-guiding torpedo made the Alarm, with her fixed smoothbore and her old-fashioned spar torpedoes, so obsolete and useless that she was stricken from the Navy List.