The San Francisco Call. Newspaper, September 6, 1903, Page 14

14 THE ONf/ e e e———Ce—— TVE B S O e AN s simat . e o e el i R P L e A{ Anchored In the mouth of Oakland Creek, where 1t is bus- fly engaged in lifting the bottom of the bay and depositing it across the breakwater, that the channel may be deepened the largest d.edger in the world may be seen. It is the prop- erty of the American Dredging Company, composed entirely of men of this State and is called the Uncle Sam. It was entirely constructed here, the capital for it furnished by local men, and it is engaged in making imperative improve- ments in the bay under a contract with the United States. This dredger exceeds in size and capacity anything of its kind, not even excepting the immense machines which were constructed for digging out the Panama canal. It is a com- bined *“clam shell” and hydraulic dredger and the only one of its kind ever bullt. It was constructed especially for har- bor improvements and for reclamation work upon the tidal and overflowed lands along the banks of the Sacramento and San Joaquin rivers and their tributaries. The building of it was directly instigated by the determination of the ‘War Department to let large contracts for dredging the har- bor. For this work it Is admirably equipped and its energies will be engaged for the next two years by the Government on contracts for harbor improvements already let. Locking at thé sturdy craft as it rides on the smooth waters of Oakland Creek it seems hard to realize that within its compact limits are crowded the most powerful engines on the Pacific Coast and that $175,000 worth of machinery and timber are contained in the narrow space. The lumber alone in the hull would make a small forest, there being almost 6,000,000 cublc feet used. The main engines operating the bucket when the dredger is worked as a “clam .shell” machine are the most powerful ever used for this purpose. They are of the upright marine type, are quadruple triple expansion and are capable of de- veloping 1250 horsepower, running 200 revolutions a minute under 200 pounds of steam pressure. In constructing the foundations for these engines 35000 feet of lumber was used. The *“A” frame which supports the boom is the most massive ever built on any dredger and welghs more than fifty tons. It is more than sixty-two feet high from the deck and is made of six 24x24 timbers for side legs and two 18x24 timbers for back legs. At the top there is a solid cast iron cap weighing abouf 18,000 pounds. From this the topping lift is run to the end of the boom, and supports the weight of the boom and bucket or ladder as the requirements may be. When working the dredger as a “clam shell” machine & boom 160 feet long and _mu inches square is supported by the “A” frame. At the ehd of the boom are two large steel sheaves six feet in diameter in frames weighing three tons, over which are run the cables operating the ‘“clam shell” bucket. These cables are 1% inches in diameter and have & combined tensile strength of 300 tons. The bucket use. is made of steel and opens and closes like a pair of shears. The shells are shaped like rinds on a quarter of an orange when opened and when closed they form a half sphere. This bucket weighs empty 32,000 pounds and will lift In good stiff material twenty cubic yards, weighing thirty tore. This enormous lcad, together with the bucket, welghina in all more than forty-five tons, Is raised from the bottom of the bay, swung a distance of 250 feet, emptied and the bucket returned to its starting point in less than one minute. It is remarkable with what ease the operator can handle this great crane. He Is put to no more exertion than would be required to lift his cap. In the hull at each side, near the legs of the “A" frame, and in the center of the hull aft and to one side are located four “spud casings,” each forty-two inches square and thir- teen feet long, weighing twelve tons each. In these casings are placed the “spuds,” which are not the potatoes used in the galley, as some may suppose, but timbers eighty fee! long and thirty-six inches square, which plerce the hull anc rest on the bottom of the bay. These are used to ancho: the dredger in any position desired without the use of cable: or lines to the shore, and are raised and lowered by cables By the manipulation of these the heavy hull may be swung around to any position by merely touching the necessary levers, At present the dredger is being operated as a hydraulic machine, which means that the bottom of the bay is ground up by an immense steel shaft on the end of which is a cutter and then pumped through long lines of large pipe, the debris being deposited In some cases 7000 feet away. As an example of the power used In ralsing this immense stream of semi- solld materfal the writer was shown a plece of iron welghing 15 pounds that had been pumped through this huge pipe without the slightest difficulty and dumped where the other debris is deposited. Located in the hull on the kelsons are the bollers, pumps, ofl tanks, water tanks, condensers, evaporators, main engine and blacksmith shop. On the main deck is the kitchen and dining-room to accommodate sixty men; storeroom, electric department, swinging engines, drums and frictions, machine shop, alr compressor, and cutter engines on the forward deck. On the hurricane deck are located the water tanks for the galley and the staterooms for the crew. There are accom- modations for sixty men all told, which is the numerical strength of the crew. Above the staterooms is the pllot house, forty feet above the main deck, in which are located all the levers, gauges, etc., and from which point the plant is operated. From this elevation a clear view is obtainable of all the surroundings and of -the pipe line running ashore. At night the whole plant is {lluminated by electricity’and the pipe line works on uninterruptedly from dusk till daylight.