Dredging creates new land

Dredging is one of the defining industries in the Netherlands. Market leader IHC Merwede cuts a lot of steel to build the specialised vessels that are used worldwide to deepen waterways and reclaim land.

The Dutch may not be ruling the seven seas any more, but they certainly know how to keep them out. With about 20 percent of its land mass below sea level, the aptly named Netherlands (Low Countries) have, since time immemorial, fought a continuous battle against the sea. Sometimes they lost, but ultimately they created a safe and prosperous nation on dry land, much of which has been reclaimed from their old enemy. This is because the Dutch are renowned the world over for their skills in dredging and land reclamation.

Dredging is an excavation activity typically carried out underwater with the purpose of gathering up bottom sediments and disposing of them at a different location. This technique is often used to keep waterways navigable, but it is also used as a way to replenish sand on some public beaches, and create land where there was no land before.

Many of the mighty machines that are used to create land where once there was sea are built by IHC Merwede, a shipbuilding company with its headquarters just southeast of Rotterdam. IHC Merwede specialises in building dredging and mining vessels and equipment and innovative ships and supplies for offshore construction.

Sebastiaan de Vreede is group supervisor at IHC Merwede’s machine shop in the town of Sliedrecht, Netherlands. Some 15 to 20 small to medium-sized IHC Beaver cutter suction dredgers are launched here each year. The yard also produces custom-built vessels and large components for offshore installations and for the huge hopper dredgers that are built at other IHC Merwede group shipyards.

The workshop is with a jungle of gantry cranes, welding torches, slipways and massive steel components wherever you look. Only the lightest workpieces can be lifted by hand. Most of the components here are given their final shape in one of the 25 or so machining centres that occupy de Vreede’s workshop, using tools supplied by Seco.

“This is heavy industry,” de Vreede says. “The steel grades we use, are fairly straightforward and do not require cutting-edge machining technology. But precision is as important here as anywhere. And since we have many one-off workpieces, we always need a great variety of tooling solutions that are flexible enough to adapt to new machining jobs. Over the years we have found that Seco Tools can cater to most of our varied requirements. Moreover, their price/quality ratio is just right, and their tool life is excellent.”

Arthur Mooren, Technical Sales Engineer at Seco Tools Benelux, has recently inherited the relations forged by his predecessor, but he has been familiar with IHC Merwede for many years. “Land reclamation is one of the nation’s flagship industries,” says Mooren. “It means a lot to us to have such a longstanding partnership with a prestigious company like IHC Merwede. On several occasions we have developed and produced customized tools for them.”

Mooren recalls that IHC Merwede once needed a tool that had gone out of production for quite some time: “They needed a milling tool with a very slender profile, with no room for internal cooling channels. For this particular job, internal cooling was not required. But a tool without it was not available on the market any longer, so, at IHC Merwede’s request, Seco reinitiated a production batch of ‘old school’ mills.”

The price of tooling is important, as are productivity, precision and tool life. But to any product there is one quality that only time can provide: Trust. And after 25 years, IHC Merwede and Seco Tools have built up a great deal of it. Says de Vreede: “We often work with new machining solutions for one-off components, so we occasionally run into problems where some extra expertise is required. Whenever we call Seco, we can be absolutely sure that they are here in a jiffy to help us solve any issue. And because they always deliver within 24 hours, we can afford to limit our inventory to a bare minimum, which is a cost saver in itself.”


By Jan Tazelaar Photos by Malou van Breevoort


The history of IHC Merwede goes back to the 17th Century, when large parts of the Netherlands were permanently reclaimed from the sea. It was then that the foundations of modern dredging technology were laid. The Industrial Revolution sparked off a new era of huge civil engineering projects and mechanised dredging, after which a number of specialised shipyards came into being. In the past century many of these shipyards joined forces, culminating into IHC Merwede in 2005. In its present form, IHC Merwede is the global market leader for dredging and mining vessels and equipment, and a supplier of innovative ships and components for offshore construction. The company has over 3000 employees worldwide, of which some 250 are employed at the shipyard in Sliedrecht.


The Double Octomill

Over the years, IHC Merwede has adopted many of SECO ’s pioneering products. A favourite is the Double Octomill R220.48 facemilling cutter, invented by SECO , which has 16 cutting edges per insert. It is a very economical solution, as it significantly reduces the cost per edge. The Double Octomill is versatile, too, because it can be used for both roughing and finishing, and is available in eight different geometries.

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