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this point by a clip which engages the stem. To the end of the boom are attached the towing ropes. When not in use, the forward end of the boom is hoisted to an almost vertical position and lashed to the deck at that point. The principal advantage of the boom is that it may be attached to a ship without docking her.

The third and most desirable device is the sliding bar shoe. This consists of a round steel bar bent into "V" shape, at an angle. of about 60°, which is lowered to the forefoot from the cathead as shown in the figure. The shoe may be plainly seen in position just above the holes in the skeg. A preventor chain is also attached to the cathead of such length that the shoe cannot slide below the skeg. Two backhauls, one on either side, are used to steady the shoe as it is being lowered or hoisted.

It is not feasible to use the sliding shoe except on ships with practically a straight stem. As it happened, the Emergency Fleet Corporation's ships under construction were designed with a straight stem and most of them required only a small stem extension or skeg to extend the straight stem down to the keel line to permit of the use of the sliding shoe.

The great advantage of the sliding shoe over the clump and chain is the fact that there are no chains in the water to retard the speed of the vessel, except when the paravanes are being used. Even then there is only one chajn for the shoe as against four in the case of the clump and chain.

In connection with the operation of paravanes there are also required suitable davits or derrick booms of sufficient strength to take a four ton load. These are used in launching and picking up paravanes. Winches of reasonable speed and power are also necessary, as well as certain special fittings which will be described later on.

Organization and Operation of Instruction Course. When the arrangements were being made to organize the instruction force, including the operation of the Berkshire, a difficult situation arose in regard to a commanding officer qualified to operate paravanes and instruct personnel. At that time no American naval officer, outside of the Bureau's representative, had had sufficient experience with paravanes to enable him to conduct the instruction course, including the operation of the paravanes. However, one American ship, the New York, of the American

Line, had been fitted with paravanes in Liverpool some months previous, and by special arangement with the Bureau of Navigation, her chief officer, Lieutenant H. R. Lewis, N. A. R., was called into active service temporarily for this duty. Under his instruction, Lieutenant C. C. Jones, the former commanding officer of the Berkshire, qualified for the practical operation of the paravane gear in about a month, and at the same time a reserve officer, Lieutenant W. W. Nutting, U. S. N. R. F., studied the theoretical side of paravanes, and was very soon able to conduct the lecture on paravanes on the instruction ship.

A lecture room was fitted up on the Berkshire, and a moving picture machine was installed for the purpose of exhibiting three moving picture films showing the manufacture, testing and operation of paravanes. These confidential films, taken by Vickers Limited in England, by arrangement with the Admiralty, were secured by the Bureau through the naval attaché at London.

The daily course of instruction consisted of a lecture on paravanes, exhibition of moving picture films, and instructions in setting paravanes for depth. Then the class proceeded to the deck where the operation of the three different types of towing devices was conducted and explained. Finally, the paravanes were launched and the vessel bore down on two mines previously laid by the mine layer Bivalve, which were promptly cut with the paravanes. The vessel was then headed for her base, the paravanes were picked up and the towing points hoisted up by whatever device the Berkshire was using at the time. Also any part of the operation not clear to any of the class was repeated. The description of the operation of paravane gear will not be given in detail, for the reason that actual instruction on a ship is necessary before the gear can be successfully handled. There are four separate parts in the operation: First, lowering the towing points to the forefoot; second, launching the paravanes; third, picking up the paravanes; fourth, hoisting up the towing points. The lowering and hoisting of the towing points have already been briefly described in connection with Fig. 6.

The launching is the difficult operation, as it is always desirable. to launch paravanes with the least possible interference with the speed of the vessel. The important factor in launching is the control of the slack in the towing rope. Before launching, the towing rope is led from the forefoot to an easing out hook at

the rail, about 75 feet from the stem, thence to a carpenter's stopper and thence to the paravane on deck. The carpenter's stopper is a special clamp which grips the towing rope without damage to the rope, its purpose being to prevent too much slack from being dragged forward by the pull of the water on the towing rope. The paravane is hoisted by the inhaul rope from the deck, and swung outboard ready to lower into the water. The carpenter's stopper is then released. Then the paravane is lowered to the water and the inhaul rope slacked off very fast, the paravane then towing from the easing out hook at the rail. When the paravane is seen to be running steadily, the easing-out hook is slacked off gradually until it reaches the water's edge. At this point the easing out hook, a specially constructed releasing hook, is tripped, and the paravane then tows direct from the forefoot in its proper position.

The method of launching used on merchant ships requires a vessel to reduce her speed to about knots to get her paravanes safely into the water. The reason for this is the position of the planes of the paravane when they strike the water. The inhaul rope referred to above is attached to an eye back of the cutterhead, and when lowered by this eye the planes of the paravane are practically parallel with the water. As they strike the water in this position, quite often the force of the water will turn the paravane in toward the ship instead of away from it. When this occurs, it is necessary to hoist the paravane out of the water and launch it again.

To obviate this trouble, naval vessels are usually fitted with a special pendant and releasing hook for dropping paravanes in the water. This hook is attached to an eye on the paravane near the center of gravity, but so located as to give the paravane just the right tilt as it enters the water. By this method, the force of the water always catches the right side of the planes and the paravane immediately proceeds down towards its proper position. Naval vessels with this gear are able to launch their paravanes at a speed of 12 knots.

On American ships, picking up paravanes is a comparatively simple operation, but requires that the speed of the ship be reduced to about 7 knots. Even at this speed, the operation puts a severe strain on the winch and derrick with which the paravane is hoisted. The inhaul rope leading over the same derrick

by which the paravane is launched, is hoisted slowly until the paravane reaches the surface of the water. At this point the speed of the winch is increased, so that the paravane is hoisted quickly up to the head of the derrick. British naval vessels, however, do not use an inhaul rope and, therefore, have to heave up the towing points first, then under-run the towing rope with a line attached to the derrick. By this line, the paravane is tripped clear of the water, after which another line is hooked on to the paravane for hoisting it on board. This method requires that the derrick from which the paravane is tripped be placed at a definite distance from the stem of the ship.

When the Berkshire was ready for operation, a base for her was established at City Island, near Pelham Bay Camp. This location brought her within easy reach of New York City, and also gave her a deep water course in which to operate. The schedule followed was to send the Bivalve out into Long Island Sound, some time ahead of the Berkshire, to lay the two mines. The Berkshire followed slowly, and by the time the lecture had been completed, and the operation of launching paravanes had been exhibited, she would reach the mines and cut them.

The otter gear instruction office was established in the office of the superintending constructor, New York City, to which all officers and men ordered to take the instruction course were required to report for identification and vise of orders before. they were allowed to go aboard the Berkshire: Each man was also required to sign a register on board the Berkshire.

Inspection of Manufacture.-As the information secured. abroad showed that the greatest care must be taken in the manufacture and inspection of paravanes, an inspection force was organized with headquarters at the superintending constructor's office, New York City. Several inspectors were assigned to the E. W. Bliss Works, and several were sent to the principal subcontractor, the Bossert Corporation, Utica, New York. This inspection force not only had to watch the detailed manufacturing with great care, but it developed that due to the great rush of government business of all kinds, the matter of priorities had to be carefully followed up by the inspectors to prevent delay in the shipment and delivery of raw materials to the contractor. To the credit of the inspection force, it should be stated that the first paravanes of each type manufactured in this country passed

the service test on the first run, and the percentage of failures was very small compared to the percentage of failures of British paravanes tested in this country.

Lieutenant Joseph F. Edwards, U. S. N. R. F., was placed in charge of this organization, and most of the credit should be given to him. He worked faithfully, and with unceasing activity up to the time of his sudden death from pneumonia following influenza on October 13, 1918. As an example of his devotion to duty, up to the end he continued to direct the work from his death bed, and finally when he became delirious he continued to talk of paravanes.

Inspection of Merchant Ship Installations.—As previously stated, the fitting of the emergency fleet vessels with otter gear was started under the advice of and carried on under the supervision of the Navy Department. The Bureau, therefore, organized an inspection force to inspect otter gear on Emergency Fleet Corporation vessels, during the construction and after completion, to be sure the gear was properly installed and in workable order. The chief inspector was established in the office of the superintending constructor, and inspectors were stationed at Norfolk, Philadelphia and Cleveland. A detailed report on each inspection was forwarded direct to the Bureau.

The entire paravane organization, under the direction of the Bureau, including personnel on the testing ship and instruction ship, contained 27 officers, and 231 men.

New Launching Hook.-The daily operation of the instruction ship gave an opportunity for making experiments in launching paravanes. The method in use by merchant ships, already described, required a ship to slow down to 7 knots to launch her otters, making her at the time an easy target for submarines. This was due to the fact that the plane being in horizontal position would often catch the force of the water on the wrong side and drive the paravane into the ship's side. Fig. 7 shows the paravane being launched according to this method as established by the British practice. It will be noted that the plane in this picture is practically horizontal.

The Bureau by experiments developed a launching hook attached to the body of the PV. through which the inhaul rope is led, giving a tilt to the plane, as shown in Fig. 8. This hook is so designed that it holds the inhaul rope firmly when under

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