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"Esso Zurich (1)" - Building a 26,000 ton Supertanker - Part -1
From : Pacific Marine Preview, Volume 45, December 1948
THE Esso Zurich, at present Hull 566 of the Sun Shipbuilding & Dry Dock Company at Chester Pennsylvania, is the first of fourteen sisters which will be built for the Esso fleet by the summer of 1950. Into their design and construction are being poured all the knowledge and skill accumulated in the sixty-two-year history of the specialized vessels cal-led tankships.
The Jersey Standard tanker fleet of 131 oceangoing ships, plus 84 special types such as lake tankers, is already
larger than before the war, despite a wartime loss of 84 vessels. The fourteen new ships, costing more than S75
million, will add to the fleet 3,192,000 barrels of cargo capacity - the equivalent of a train of standard tank cars just over 100 miles long. This formidable investment in the future of the oil business is a measure of the world's in-satiable, and still growing, demand for petroleum. It is also an indication of the increasingly critical role of transporta-tion in meeting that demand, as an ever larger proportion of the world's oil is supplied from areas remote from the great oil-consuming population centers.
One of these remote areas is the Middle East, whose enormous petroleum reserves are counted on to supply an in-creasing share of the oil needs of western Europe. At present, tankers are moving some 925,000 barrels of crude oil daily from Persian Gulf ports. The approximate equivalent of 350 tankers, each of about 138.000 barrels capaci-ty, is engaged in this trade, and two-thirds of the ships are making the long, uneconomic haul around the Arabian peninsula, through the Suez Canal and the Mediterranean to western European countries.
Although this movement of oil is greater than ever before, there are enough tankers to meet today's needs.
However, the expected expansion in Middle East crude oil production and in Eastern Hemisphere refining capaci-ties will impose an increasing load on oil transport facilities m that part of the world.
Pipelines are counted on to carry much of this load by moving crude from the Persian Gulf to the Mediterranean. But these pipelines are as yet unbuilt, and indefinite delay in completing them would throw the entire transport burden upon tankers. This would require new tanker construction on a scale far greater than now anticipated and at a cost in steel far higher than that of the pipelines. Furthermore, until the additional tankers were made available, it would probably prove necessary to withdraw a number of existing tankers from service elsewhere in the world or limit oil shipments from the Middle East.
A ship which carries a fluid cargo ( whether petroleum, liquefied gas, vegetable oil, molasses or something else; is not necessarily a tanker. She may carry it in barrels or even in built-in tanks, but she does not qualify as a tankship unless her tanks are an integral part of the hull, or shell, of the ship. The first true tanker was a German vessel, the Gluckauf, built in England in 1886. Two years later came the Standard, first tanker owned by the original Standard Oil Company.
Bulk transport bv water was then, and still is, the most economical method of moving oil long distances. That is one reason why the world's tanker fleets have grown steadily until this year they totaled approximately 21 million tons of cargo-carrying capacity. More than onethird of this total was accounted for by the famed T-2s of the U.S. Maritime Commission's wartime building program.
Since they came into service, the T-2s have been a kind of yardstick with which other tankers were compared. At so-me future time, the yardstick may be the "supertankers," of about the Esso Zurkh's size and speed, now being built for Jersey Standard and other U.S. tanker operators.
Here's how the Esso Zurich shapes up alongside a typical wartime T-2 :
A tanker, reduced to her essentials, is a collection of floating tanks, plus machinery to propel her and pump her car-go, and living space for her crew. The designer of the Gluckauf might be pleased if he knew that, sixtytwo years later, tankers were still being built along the general lines which he conceived for the first petroleum steamer in history.
Nearly all tankers, ever since, have followed this plan. Their living and working space is at the after end, except for the midships house where the bridge and deck officers' quarters are located, and the forecastle or forward end where the windlass and anchor-chain hawse pipes, are located. Amidships lie the cargo tanks, under a long deck so low that seas often sweep across it. Since there generally is no pasasge through the cargo space below this deck, a railed walkway runs about eight feet above it. These features give the loaded tanker her characteristic
and unmistakable silhouette - three widely separated humps on a hull almost awash.
The oil tanker is unique among cargo vessels in that she is a one-way carrier. Her job is to move petroleum, whether crude or refined, to areas where it is in demand. Seldom, therefore, does she have a return cargo. When her tanks are empty, she rides the waves as lightly as a cork, and about as unmanageably; so on her return voyages sea water is pumped into her tanks as ballast, until she has settled low enough to be satisfactorily seaworthy.
The tanker has no long, pivoted cargo booms on her masts or derrick posts, like those which distinguish a dry-cargo freighter. She has instead a complex maze of pipelines laid on her deck, with more below. From them rise hand-wheels, paintctl in different colors for easy recognition, which operate the valves controlling flow. Through these lines her batteries of pumps unload her liquid cargo.
There are "clean oil" cargoes and "dirty oil." Dirty, or blacky oil is crude petroleum or a product like bunker fuel; clean oil is refined petroleum such as gasoline. The clean-oil tanker often has the problem of carrying a variety of products - gasoline of different specifications, fuel oils, lubricating oils of many grades, weights and colors - without mixing them up.
To do this, the pumpmen and the officers - especially the chief mate, who has a special responsibility for the cargo - need an exact mental blueprint of the ship's cargo system: every tank and pipeline, pump and manifold, header and crossover. All this euipment must be checked for leaks before loading and at regular intervals afterward. With well-trained men using careful procedure, a clean-oil tanker may carry six or eight grades of product without contamina-ting any of them.
Tanker cargoes are handled with remarkable speed. A fast turnaround ( time in port) is a mark of efficiency and a major factor in keeping down the cost of the product transported.
A twenty-four-hour turnaround was once considered exceptional for a big oceangoing tanker. However, the average T-2 can pump some 10,000 barrels an hour and usually discharges an unmixed cargo in fifteen to twenty hours. The Esso Zurich'i four cargo pumps, steam-turbine- driven, will pump 22,000 barrels an hour. Her turnaround time, with a cargo more than half again as large as a T-2's should be even shorter.
Gradual improvements in hull design and in propulsion machinery, over many years, have made possible the usful operation of a tanker so big and fast.
In the economics of bulk oil transportation by water, the aim is to minimize the "cost per cargo ton per mile." The more oil a tanker carries and the faster she steams, loads and discharges, the more cargo she will transport during her useful lifetime. On the other hand, if size and high speed send her operating costs up too sharply, some of the power will be wasted.
Of course, her size may be limited by the harbor conditions and terminal facilities in ports where she is expected to call. She might, for example, be needed to deliver products to ports along the west coast of Central America. Here are few deep-water harbors into which any ship can steam with impunity, so the tanker used in this trade must be of limited draft.
Even if her trade is to be only among the larger oil ports, a few feet of deeper designed draft might mean that she would be denied access to some of them, when fully loaded. So, when a new tanker is to be designed by Jersey Standard's marine department, one of the first considerations is to find out where she is to go and how big she may be within limits set by harbor and terminal facilities.
For all her bulk, it is worth noting that the Esso Zurich. fully loaded, draws only about a foot and a half more water than a T-2. There will be few harbors or terminals available to the T-2s where the new supertankers cannot call. As queens of the world's largest privately owned tanker fleet, they will serve the oil-consuming world wherever petroleum is to be moved by sea.
Adapted from an article entitled "Suertanker" in The Lamp, Standard Oil Company (New Jersey) publication.
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