For as far as the eye can see, a jumble of broken ships litters the pure white sands, turning this beautiful beach into a nautical junkyard.

It is the end of the line for many a once-proud ship, too old or dilapidated now to sail the world's oceans.

A slice from the midsection of a large tanker stands upended in the sand not far from what once was a ship's cabin. The spots where the sailors' bunks once hung are clearly marked on the steel bulkheads.

Barefoot Pakistani workers, their heads wrapped in oily turbans, clamber over the ship sections, using their acetylene torches to slice the steel into neat plates and strips.

About 100 ships in various stages of dismemberment line a five-mile strip of beach in one of the oddest businesses in the world: the wrecking of ships for scrap steel to feed Pakistan's booming construction industry and to provide the raw material for its infant industries.

Steel is a scarce commodity in this country, which just opened its first steel mill, built with Soviet help, along the coastal desert just east of the port city of Karachi.

Previously, the only source of domestically produced steel plates and beams came from the small rolling mills fed by scrap, most of it from ships broken up along this shore, about an hour's drive northwest of Karachi.

It is a sad ending for ships, whose names now are only marked on pieces of life jackets that litter the beach or on leaky lifeboats that serve as domed roofs for some workers' huts.

One captain who had sailed his ship up and down the South American coast for 20 years took it on its only ocean voyage--across the Pacific--to end up in the Gaddani Beach scrap heap.

Pakistan's 20-year-old ship-breaking industry is the second largest in the world, behind Taiwan.

The work here is done largely by manpower instead of machines, with Pakistani workers using the most rudimentary equipment. The ships are sailed full speed onto the beaches at high tide. When the tide recedes, the workers slice off a section of the ships's bow and drag it above the high water mark with winches taken from previously scrapped ships.

Until recently, the only cranes in use were attached to old ship masts anchored 20 feet into the sand, but now one ship-breaking firm has invested in a modern rolling crane on tractor treads.

Still, the bulk of the work is done by men. It takes 175 men--only 50 of them with any kind of skill--three to four months to reduce a ship to a heap of scrap. In Taiwan, where the process is mechanized, the job is done much faster.

The heaviest work here is hauling and carrying the large and heavy slabs of steel up the beach to trucks that take them to a rolling mill. Six men were carrying one large section of heavy pipe, while a little way down the beach 20 men had a large sheet of bulkhead steel loaded onto their shoulders and were trudging to a truck.

In many ways this labor-intensive industry is perfect for Pakistan, where machines are in short supply and the work force cheap. The most skilled laborers--those who run the winches or use the torches--make about $10 a day while unskilled workers, who do the carrying, earn $3 a day.

Each company has its own little section of the beach, with an office near the road built and furnished from salvaged ship parts. The workers live in little shacks, also built from nautical scraps.

The area remains primitive. Telephones are a recent addition, but there still is no fresh water.

Buying and breaking ships, however, is big business. A medium-size wreck costs about $1 million, priced by the ton. Swedish-, German- and British-built ships cost the most, because of their higher quality steel; Greek ships are the cheapest because they are generally run-down by the time they are sold for scrap.

Until recently, only small vessels, under 7,000 tons, could be handled here. But now as the Pakistani ship breakers have gained experience, they are taking on bigger ships.

When a ship ends its final journey here, it has become a tradition for all neighboring ship breakers to gather and help.

The patch of Mohammed Khalid, the bright young manager of M.E.C Shipbreakers, is just down the beach from M. R. & Co., which is gambling that it can handle a ship as large as 34,000 tons, the size of a French tanker scheduled to arrive here. Abdul Majeed, one of five brothers who run the business, has spent more than a month studying the tanker's plans to figure the best way to beach it and break it up.

Besides selling the steel as scrap, every other part of the ship is cannibalized. A turbine, for instance, was sold for $15,000 for use in a Lahore factory while Suleman A. Memon, who is a director of molasses companies as well as M.E.C. Shipbreakers, said he salvaged 80 gauges from ships to use on the boilers at his sugar mills.

Ship breaking, a relatively new industry in this country, started on a very small scale in the mid-1960s. Last year, ships totaling 400,000 to 500,000 tons were dismembered on the beach and this year the total is expected to jump to 600,000 tons.