REPORT OF BOARD OF CONSULTING ENGINE EERS, PANAMA CANAL.


of the canal for the passage of ships in time of war strengthens the argument for a sea-level canal and makes it necessary to'consider with care the chances of suhli an event in ordinary canal operation, the facilities for handling and controlling the movement of ships which may be used, the precautions for safety which may be introduced in the operation of the locks, and the constructions which may be supplied to close off the current should it be set Lip.
 We believe that in no ship canal in the world has such a disaster occurred as that imagined for the Panama Canal. If the accidents at the Manchester Canal show that gates may be struck and destroyed, they also show that disaster may be averted even without special safeguards. Of all the possible movements of a ship at canal locks the one that involves the most danger of opening a summit level is when a ship bound down in that level approaches a lock, but by proper safeguards this can be made very small. If a gate is struck by a ship upward bound the water pressure on the opposite side of the gate helps to resist the blow. By the use of two pairs of gates at each end of the summit lock all danger of opening the sunmit level by a blow on the downstream side of the lower gates is eliminated, as will be shown a little farther on.
 The canal construction should provide long approach walls at each end of every lock or flight of locks so that lines can be put out quickly and handled readily and the ship held under perfect control. For this important purpose a lcng solid pier with suitable snubbing posts is vastly superior to mooring piles and floats, such as are used in some foreign canals. No canal in Europe is adequately provided in this respect, and the apprehensions of some members of the Board in regard to the hazards of navigation through lock canals may be due to the fact that their experience has been entirely with canals having this radical defect. With suitable approach piers and with rules duly enforced requiring ships to put out lines on arriving at the pier and to reduce speed to two miles per hour when moving along it, or to stop altogether several hundred feet from the lock, a great degree of security can be obtained. Such approach piers are provided in the lock plan herein recommended.
 This plan also provides two pairs of gates at the head and two at the foot of each summit lock, so that a ship will always find two pairs of gates shut against it.
 If the summit level is terminated by a single lock and the lower gate is struck by a ship upward bound, the gates at the upper end of the lock being open, the lower pair of gates at the foot of the lock having water pressure back of them will absorb the blow, and even if they are wrecked the second pair of gates, some 80 feet distant, will not be reached. The resistance offered by the first gates will almost surely stop the ship, and the rush of the mass of water, 80 feet in length between the two gates, will insure stoppage before it can reach the second pair. If the lower end of the lock is open and the upward-bound ship strikes the first pair of gates at the upper end of the lock its motion will be stopped by these gates, the miter wall, and the water, and the second pair of gates will be left intact. We believe, therefore, that, by the use of duplicate or safety gates at each end of the summit lock, all danger of opening the summit level by an upward-bound ship will be eliminated.
 If a downward-bound ship is approaching the gates from the summit level it will find at least two pairs of gates closed against it, of which the first will be sustaining no water pressure to weaken the strength available to stop the ship. While this case does not afford the absolute security shown in the case of ships moving upstream, the possibility that the ship will so completely wreck the first pair of gates as to continue its course to the second and seriously harm it is extremely small. A large lock gate is a massive structure, not easily wrecked. The gates of the Poe lock have been struck three times and injured more or less, but they continued to support the summit level.
 The provision of duplicate gates at each end of a lock herein adopted is an unusual precaution. It has been recently adopted in part at the St. Marys Falls Canal, where duplicate gates are now operated regularly at the lower end of the Poe lock, but the upper end is not similarly protected. In the additional lock now projected at that canal safety gates are to be provided at each end. The approach piers, the extent of which greatly affect the safety of a lock, are excellent at the St. Marys Falls Canal and far better than at any other ship canal, and doubtless have contributed to the remarkable record of .immunity from serious accidents.


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