While the completed Panama Canal does not wed the two oceans, or permit their waters to mingle in Gatun Lake, it does bring them a little closer together. On the Atlantic side a sea-level channel has been dug from deep water due south to Gatun, a distance of 7 miles. On the Pacific side a similar channel has been dug from deep water in a northwesterly direction to Miraflores, a distance of 8 miles. It follows that 15 of the 50 miles of the canal will be filled with salt water. The remaining 35 miles will be filled with fresh water supplied by the Chagres and the lesser rivers of Panama. The task of digging these sea-level sections was a considerable one and almost every method of ditch digging that human ingenuity has been able to devise was employed. Steam shovels, dipper dredges, ladder dredges, stationary suction dredges, and sea-going suction dredges, all contributed their share toward bringing the waters of the Atlantic to Gatun and those of the Pacific to Miraflores. In addition to these methods, on the Pacific side use was made of the hydraulic process of excavating soft material, washing it loose with powerful streams of water and pumping it out with giant pumps.
Hundreds of acres of low, marshy land have been filled up, either with mud from the suction dredges and the hydraulic excavators, or with spoil from Culebra Cut. Much of this made land will be valuable for tropical agriculture, while other parts will never serve any purpose other than to keep down the marshes. But they afforded a dumping ground for material taken out of the canal prism, and added something to the improvement of health and living conditions on the Isthmus. Probably the most interesting process of excavation in the sea-level channels was that of the sea-going suction dredges. These dredges took out material more cheaply than any other kind of excavating machinery used on the Isthmus. Two of them were put to work in 1908, about the time the operations reached full-blast and have been kept in commission ever since. While it cost as much as $70,000 a year to keep each one in commission, they were able to maintain an annual average of about 5,000,000 cubic yards of material excavated at a cost per yard of 5 cents and even less. With steam shovels it ranged from 10 to 20 times as much per yard. These big dredges were built with great bins in their holds and equipped Another interesting dredge used was the big ladder dredge Corozal. It is a great floating dock, as it were, with a huge endless chain carrying 52 immense, 35-cubic-foot buckets. On the center line amidships there is a large opening down to the water. The big elevator framework carrying the endless chain goes down through this and into the water at a considerable angle. The buckets pass around this, and as they round the end of it their great steel lips dig down into the material until filled, then they come up at the rate of three every five seconds and deposit their burden in a huge hopper which conveys it to the barge at the side of the dredge. The dredge is anchored fast at a given place, and keeps on attacking the material beneath it until the desired level is reached. This dredge, with the sea-going suction dredges, will be retained as the permanent dredging fleet. The stationary suction dredges at the two ends of the canal were used to pump up the soft material and to force it out through long pipe lines into the swamps or into the hydraulic cores of the earth dams. Several old French ladder dredges were rescued from the jungle and put into commission at the beginning of the work, and they held out faithfully to the end, dividing honors with the newer equipment in hastening the day when the oceans might go inland to Gatun and Miraflores. While they looked like toys beside such giant excavators as the Corozal, they probably showed more Another interesting machine used on the Pacific end of the canal was the Lobnitz rock breaker. This consists of a sort of pile driver mounted on a large barge. Instead of a pile driving weight there is a big battering ram made of round steel, pointed at one end. It is lifted up perhaps 10 feet and allowed to drop suddenly. As some of these rams weigh as much as 25 tons their striking force may be imagined. When the ram struck the rock the top would shake back and forth like a bamboo pole, in spite of the fact that it was made of the best steel and more than 15 inches in diameter. Sooner or later the rams would break off at the water line, this being due to the fact that the constant flexion at that point set the molecules in the steel and took away all its elasticity. It was found desirable to excavate a part of the sea-level channel before the water was let into it. To accomplish this a big dam, or dike, was built across the channel several miles inland, and steam shovels were used behind this dike. As the work neared completion, however, it was found advisable to let the water come further inland, so that the dredges could extend the field of their activities. To do this another dike was thrown across the channel about a mile north of the first one, The distinguishing features of the ends of the canal are the big breakwaters at Toro Point, at the Atlantic end, and Naos Island, at the Pacific end. The former extends from the shore out into the sea for a distance of 2 miles and has a large lighthouse at the seaward end. It was built by dumping stone from the shore out into the sea, this process being followed by driving piles into the dumped stone and building a railroad on the crest, over which the stone was hauled for its further extension. The top of the breakwater is covered with huge stones weighing from 8 to 20 tons each, these to make sure that it will stand against the pounding of the waves. Two minor breakwaters were also built at the Atlantic end to protect the terminal basin. The big dike at Naos Island in the Pacific is more than 17,000 feet long and transforms the island into the cape of a small peninsula. There was a threefold purpose in its construction—to cut out the cross currents that brought thousands The last part of the canal work to be completed will be the terminal facilities at the ends of the big waterway. At the time this book went to press they were something more than a year from completion, but the indications were that they would be finished within the time limit originally set for the completion of the canal itself. These terminal facilities consist of dry docks, wharfage space, storehouses, and everything else necessary to perform any service that might ordinarily be required for passing ships, whether they be those of commerce or of war. The main coaling station is to be established at the Atlantic end. The storehouses, the laundry, the bakery, and the other equipment of the Isthmian Canal Commission and the Panama Railroad also will be made a part of the permanent terminal plant on that side of the Isthmus. There one may sit and see ships coming into the canal, tying up at the docks, sailing up the big ditch, and passing through the locks at Miraflores and Pedro Miguel. Near by will be the permanent home of the marines who will be stationed on the Isthmus, their barracks and grounds occupying the broad plateau on the side of Ancon Hill made by taking out the millions of cubic yards of stone required for the concrete works on the Pacific side of the Isthmus. Two permanent towns will be built at Balboa, one for the Americans and the other for the common laborers. The American town will be built under the capitol hill on a broad plain that was made by pumping hydraulic material into a swamp and by dumping spoil from Culebra Cut. It is certain that none of these port works will ever fail by reason of insecure foundations. Wherever unusual loads were to be carried great piers of reinforced concrete were sent down to solid rock, often a distance of 60 feet below the surface. They consisted of a hollow shell of reinforced concrete which was allowed to sink to hardpan of its own accord or under heavy weight. These shells were built in sections 6 feet high. The bottom section was 10 feet in diameter, and the lower end was equipped with a sharp steel shoe. As the section cut down into the earth of its own weight and that above it, laborers on the inside removed the material under the shoe and as they did so it sank further down. The sections above were only 8 feet in diameter, and did not quite fill up the hole made by the bottom of the section, thus overcoming all skin friction, and permitting the full weight of the series of sections to fall on the lower one. A jet of water was forced around the sinking pier all the time it was going down, and this made its progress the more easy. At times the weight of the superimposed sections was sufficient to force the pier down through the soft mud, while at other times the material became so The coaling plants at the two terminals will be the crowning features of the terminal facilities. With an immense storage capacity, and with every possible facility for the rapid handling of coal, both in shipping and unshipping it, no other canal in the world will be so well equipped. The coal storage basin at the Atlantic end will hold nearly 300,000 tons. This basin will be built of reinforced concrete, and will permit the flooding of the coal pile so that one-half of it will be stored under water for war purposes. It is said that deterioration in coal is not as great in subaqueous storage, and at the same time the pile is less subject to fire. The plant will be able to discharge a thousand tons of coal an hour and to load 2,000 tons an hour. Ships will not go alongside the wharves to be coaled, but will lie out in the ship basin and be coaled from barges with reloader outfits. Special efforts have been made to provide for the quick loading of colliers in case of war. The coal There will be big supply depots where ships can get any kind of stores they need from a few buckets of white lead to an anchor or a hawser; a laundry in which a ship's wash can be accepted at the hour it begins its transit of the canal, for delivery by railroad at the other end before it is ready to resume its ocean journey; an ice plant which will replenish the cold storage compartments of ships lacking such facilities. In short, it is proposed to attempt to do everything that may be done to make more attractive the bid of the canal for its share of business. |