A few weeks ago, a year after it had closed its crawler crane plant in Manitowoc, Wisconsin, the iconic crane maker that started in that lake-side city in 1902 announced that it was moving its corporate headquarters to Milwaukee. Locally, the move that was described as “the end of an era”, as the last vestiges of that business moved away from the city from which it took its name. Not that Manitowoc crawler cranes have ceased to exist. Over the past several years production has been moved to the Grove crane plant in Shady Grove, PA, a move that by all accounts has been well-handled by the ‘new’ company management and that is yielding positive results.

Sadly, many good, talented and loyal employees have lost their jobs, directly or indirectly, as a result of this relocation. However, while many will mourn this development, it did not come as a complete surprise. Over many years there were far too many labour disputes that interrupted production, delayed deliveries and arguably impacted quality and costs. But management must also take a big share of the blame.

After dominating the world’s heavy lift crawler crane market with their big red mechanical cranes through the 1970s and 1980s, Manitowoc, to many, appeared oblivious to the advances and advantages in hydraulics that were all around and plain to see. While Manitowoc’s 1992 introduction of the 250t M-250 hydraulic crawler crane and its subsequent successors in the 200–400t classes proved very successful, market leadership had been handed to the competition. Now, with the patented Variable Position Counterweight (VPC), the future is quite possibly looking much brighter. But, it’s too late for the city of Manitowoc.

Nevertheless, if the VPC can ultimately leave a mark on this industry even close to that of the Ringer it will be a great success indeed. For, without question, the defining invention in the development of heavy crawler cranes by Manitowoc was the Ringer. Conceived by contract manager Dan Beduhn in 1965/6, the Ringer became the most popular capacity-enhancing device for mobile cranes that the industry had ever seen.

However, it would be misleading to give all the credit to Dan Beduhn, talented engineer though he was. For it was Manitowoc president John West who, in 1964, crossed the Atlantic to visit Bauma in Munich where he took note of a new 30USt capacity lattice truck crane manufactured by M.A.N. That crane was encircled by a large steel ring—the design of Hans Scheuerpflug, who was awarded German patent 1,185,353 on September 9th 1965. So, the engineers at Liebherr, Gottwald or Demag may well have been looking at this concept too.

Doubling or tripling the lifting capacities of Manitowoc’s popular 4000W (150-200USt), 4100W (200-230USt) and 4600W (350USt) cranes, Ringer cranes established themselves by their hundreds at the very heart of the global petro-chem boom, the Middle East and North Sea oil booms, while all the time building numerous mega production and processing plants and urban infrastructure worldwide. To some extent, those mechanical Manitowoc Ringer cranes were superseded during the 1990s by the manufacturer’s hydraulic M-1200R (1,200t) and 888R (600t) Ringers. Impressive as those new generation hydraulic lattice boom cranes were, they were much larger-capacity cranes and consequently their sales volumes and market impact were relatively modest.

Many years previously, Manitowoc had recognised the fundamental limitation of the Ringer—its immobility—and developed ‘travelling ringers’, and so on. But this weakness was inescapable and ultimately sounded the design’s death knell. Somewhat contrarily, many ‘old’ Manitowoc Ringers have been mounted on barges or ships, doing sterling work in rivers, ports and offshore applications, gaining the mobility on water that they lacked on land.

Big and nimble

It was mobility that for more than three decades propelled the sales of similarly large crawler cranes made in the neighbouring Northern US state of Minnesota, by Manitowoc’s arch rival, the American Hoist & Derrick Company based in St Paul.

In 1959 Mitchell DeCuir conceived of a ‘Mobile Guy Derrick and Counterbalanced Crane’, labelled a ‘3-in-1’ crane, that yielded US Patent 3,202,299 awarded on August 24 1965 and assigned to the inventor’s son, T S DeCuir.

This was followed up in October 1968 when another two great American Hoist crane designers, Archer W Brown and James L Montgomery—who later became VP of engineering—filed a patent application that would result in the award of US patent 3,842,983 for what would become known throughout the crane world as the Skyhorse.

While not necessarily delivering the same level of lift capacity enhancement as the Ringer, the on-site mobility afforded to Skyhorse-equipped American cranes, base-rated between 165–450USt (150–400t) capacity, was every bit as appreciated by crane rental companies and contractors worldwide. Due to space and capacity constraints, starting in the early 1970s the larger-sized 250–450USt (225–400t) 11000 Series American crawlers were produced not in St Paul, but at the company’s expansive Industrial Brownhoist plant in Bay City, Michigan, which offered waterfront docking facilities. Of course, like Manitowoc, Harnischfeger P&H, Koehring, Lorain and scores of other US crane and construction machinery manufacturers, the production facilities of ‘The Hoist’ were all located in the heavily unionised mid-west.

Ultimately it was local labour issues and high costs that couldn’t be sustained, causing the company to shut up shop in St Paul and move south to Wilmington, North Carolina in 1985. To be fair, by then the company’s crane line was bordering on technical obsolescence. More than a decade later, in 1998, with the firm in dire straits, it was acquired in a bold move by Terex and in 1999, with the American bran0064 still strong, an OEM supply deal with Japan’s IHI dramatically revived its fortunes.

Predictably, over time, other manufacturers adopted similar capacity-enhancing solutions. After a long, drawn-out patent infringement lawsuit, FMC Link- Belt won the right to employ a Ringer-type device that additionally offered a degree of mobility on its new, large-size hydro-mechanical crawler cranes, enhancing their capacities up to 700USt (634t). But, fine machines as they were, they arrived too late in a market heavily-dominated by Manitowoc. Once the patent issue was clear, Manitowoc’s fierce rival American Hoist developed its own ‘Ring Horse’ while others like Italy’s Italgru, NCK-Rapier and even Mannesmann-Demag also adopted various similar ‘Ring’ solutions. Today it’s clear that American’s Skyhorse has had the broadest and most profound effect on large-size crawler cranes over these past 30-years, and this persists today.

Carrying counterweight

These days large-size crawler cranes with derrick masts supporting heavy counterweights deployed at wide radii of 10–20m over the rear of the crane are a common sight—every manufacturer of larger-sized crawler crane offers these devices.

Initially, these auxiliary counterweights were carried on wheeled trailers attached to the rear of the crane and prescribing a wide radius. As they developed, their sophistication was enhanced, with motorised, steerable trailers and then with telescopic connections to the crane, allowing variable radii and corresponding lifting performance.

At the same time, it became clear that trailer-mounted auxiliary counterweights were not the only solution.

Floating the counterweight just above the ground had the major benefit of reduced capital cost as well as reducing expensive and time-consuming ground preparation.

As time has gone by, these benefits have proven increasingly attractive, especially on wind farms where regular moves are involved.

Certainly, during the 1960s and 1970s the German and Japanese manufacturers recognised the benefits of hydraulics and pioneered their use on crawler cranes, and it’s easy to criticize the fact that those great American pioneers were slow to switch to hydraulics. But often, when a major technological change occurs, there’s more at stake than simply keeping up-todate with the product. Companies such as American Hoist & Derrick Company and Manitowoc had over many decades refined their art, invested countless millions in the hundreds of machine tools needed to cut, turn and weld their mechanical masterpieces, and most critically had factories staffed by many hundreds of highly-skilled machinists and technicians. It was not an easy change to make.

Closing factories and laying off loyal skilled workers is, and should be, very difficult. For while a mechanical crane is, or was, a product largely designed top–bottom by the engineers and workers employed by the crane manufacturer itself— in contrast, the hydraulic crane is a product that is substantially ‘assembled’, generally involving components such as motors, valves, and cylinders, made by and purchased from third parties.

Consequently, much of the process of designing the crane is significantly different, and so the factory equipment and functions as well as, critically, the employee skills needed to manufacturer the crane, are also radically different.

It amounts to an epoch change. It is considerations such as these that lie at the heart of why, with few exceptions, most of the great makers of mechanical cranes, excavators, and so on, failed to make the transition to hydraulics.

This is not to take anything away from the new companies that generally emerged in the 1950s and 1960s, starting up at the dawn of the hydraulics age in which we continue to live.

Contrary to some misinformed propaganda, the first fully hydraulic crawler crane was not made in Germany or Japan but in Britain by excavator pioneer Hymac in 1968. However, the major developments in hydraulic lattice crawler cranes must be credited to Japan’s Hitachi, Sumitomo and Kobelco as well as Germany’s Sennebogen, Liebherr and Demag. But, when it comes to ‘heavy lifters’ most of the accolades are due to Demag, Liebherr and more latterly Kobelco. Of course, all of these manufacturers were, in many respects, building their products along the paths first beaten by those who made mechanical cranes in Minnesota and Wisconsin. The essential geometry, structures, applications, and so on of the large crawler crane had already been well established. That made it much easier.

But the challenges were changing. No longer was it just about more lifting capacity or reach height. Materials had been evolving since the first use of 100,000psi T-1 steel by Manitowoc, American and P&H in the 1960s. Stronger and lighter but also more brittle and flexible these steels were expensive, demanded much-enhanced welding skills and selective application. Safety legislation too was advancing rapidly, placing heightened demand on crane engineers. But the evolution of personal computers, domestic electronics and computer-aided design ushered crane technology through the 1990s and into the 21st century. At a ‘user’ level, customers were demanding easier use, better control, more information, easier and faster erection and much improved transportability. A tall list of demands indeed, but one to which the industry welcomed and rose to rapidly and with enthusiasm.

As will be appreciated from the accompanying tables listing more than 80 crawler cranes in the 400–800t class—not to mention the long list of lattice truck cranes that some years back outsold crawlers—this is a category that has garnered the attention of more than a dozen manufacturers over the years, and indeed has grown in popularity.

Two factors primarily drove the growth in crane models. One of them is not that these cranes sell for very high prices, for with such strong competition coupled with the enormous engineering effort required and the relatively small volume of global sales (100–140 in a good year) this is not a business for the faint of heart.

The actual motivating factors were, and indeed are, the growth in development of wind energy and secondly, the emergence of China as both a major consumer of large crawler cranes as well as an important producer.

A generation ago the cranes, and larger models, were heavily involved in the construction of conventional as well as nuclear power plants where the demands were all about lifting capacity and over-reach. Wind turbines offer a substantially different set of challenges. The weights are not great, typically 30–80t, but the pieces such as rotor blades are very long and cumbersome and most significantly the tower heights keep getting taller. Towers of 80–100m are increasingly common and by no means the maximum. For land-based wind farms, the size of crane required has increased from 250–300t models 15–20 years ago, to 600–750t today. But it’s not just about ‘size’, particularly during the past ten years, crane design engineers have been engaged in a constant effort to wring performance out of their cranes that particularly suits the demands of wind turbine erection.

The ability of these cranes to operate as close as possible to the turbine tower affords many benefits. By reducing operating radii it optimises the effective lifting capacity of the crane. This means not only very steep boom angles but also combinations of long main booms with short, offset, high-capacity fly jibs. Boom and jib systems that meet these needs can be installed on most standard specification cranes. But the challenges don’t stop with the lift. Getting to and from the tower erection site is often very challenging, especially for a big heavy crawler crane. Large wind turbines are always sited at the most advantageous location for volume and force of wind conditions and that often means elevated, isolated locations— often on or near the coast.

Crawling up a steep narrow dirt road is not what crawler cranes were originally designed for. Consequently, Terex-Demag with their CC 2800-1NT and Liebherr first with their LR 1400/2-W, followed by their LR 1600/2- W, offered narrow track widths, augmented by outriggers for leveling and stability, offering ‘application-engineered’ solutions. But these traveling conditions are still hazardous for these large cranes with their high centre of gravity and regrettably several have tipped-over.

But it’s more conventional, long-distance travel that poses the problem in most countries. Not too long ago, when Manitowoc and American Hoist were in their heyday, transporting these big crawler cranes presented huge problems, especially for transport authorities and other road users. Those early big mechanical crawler cranes were designed to lift, but not to be stripped-down and transported.

Thanks to hydraulics and modular designs, crane designers learnt how to design cranes that could be easily broken down into manageable pieces, that in terms of weights and dimensions met road regulation. Breakthroughs in the ease and speed of assembly and disassembly as well as transportability were the fundamental factors for the return to popularity of the crawler crane: in the 1970s and 1980s many were ready to write off the entire ‘breed’ as yesterday’s dinosaur. Thanks to the Japanese manufacturers with their smaller hydraulic crawlers and the German manufacturers, the numerous performance benefits of the crawler as compared to wheel mounted cranes, survived.

Japanese design

It would be remiss to discuss the subject of heavy crawler cranes without talking about the major contribution made over the years by the leading Japanese players. Over the course of time Sumitomo, and more recently Hitachi-Sumitomo, have fielded important larger-sized models but, on balance, it has been Kobelco that has regularly been at the forefront. Even so, while cranes like the highly-successful 450t (500USt) 7450 have proved very popular both in Japan and the SE Asia and broader Asian markets, few models have garnered significant success further afield.

As the largest global player in the crawler crane market this past decade, obviously Kobelco has a deep understanding of the market. In the past its products have appealed largely to a domestic audience. Now with a design bureau in Frankfurt, there is the potential for change.

Big cranes typically handle more critical loads than smaller machines, and the quality of control and information afforded the operator are at their zenith.

It is in these respects that the crane engineers working with the likes, for example, of Rexroth and Kawasaki have been responsible for a quantum leap in the fine handling characteristics of today’s cranes—enabling them to manage boom and jib combinations as much as 180m.

But fundamentally, these big cranes are subject to the same laws of physics as that first little crawler crane built by Bucyrus in South Milwaukee back in 1911. And the art of optimising the counterweighting of cranes has been critical to big crane design since DeCuir first laid down his ideas that led to the Skyhorse.

These days most auxiliary counterweights ‘float’ rather that travel on the backs of trailers. It’s understandable that some may feel more comfortable with that big slab of weight safely standing on the ground, but the benefits of floating are clear to see. The ‘Ring’ may have lost favour, in most if not all quarters, but Manitowoc has continued its long history of innovating load enhancing devices with the VPC (Variable Position Counterweight) now gaining popularity with their 300 and 650-tonners. Not surprisingly, as was the case with their Ringer, the VPC has also attracted ‘emulators’.

Dedicated to crawlers

The degree to which the Liebherr Werk Ehingen (LWE)’s crawler crane business has expanded over recent years was never more dramatically illustrated than with the opening of their new, dedicated assembly hall at the end of 2008. Measuring a massive 216m long by 90m wide it was the industry’s largest facility of its kind. With a planned capacity of up to 100 large-size crawler cranes of 350–3,000t capacity, this was indeed a bold move. Two years later the Great Eastern Japan Earthquake and Fukushima nuclear disaster had a profound effect on worldwide nuclear power plant building activity. While the halting of nuclear power development curtailed much of the demand for crawler cranes in the 1,000–3,000t classes, compensation for the crane industry emerged as growing global investments in renewables fueled demand for crawler cranes and all terrain cranes particularly of 500- 750t capacity.

One of the company’s landmark developments was the introduction of a telescopic counterweight trailer for its new 400t LR 1400/1 launched at Bauma 1998. When fully loaded at 250t the trailer’s radius could be varied between 11m and 15m. The trailer was electronically steered from the crane cab and could be set for towed-travel, circular travel or to travel parallel to the crawlers. Van Seumeren (later renamed Mammoet) was an early customer, ordering five LR 1400/1s, all with the new capacity enhancing counterweight trailer.

More recently, central to LWE’s success has been the 600t LR 1600/2 which has been the best-selling crane in its class for some years now with over 100 units sold. While a little longerin- the tooth, the LR 1600/2’s big brother—recently up-graded 750t LR 1750/2—continues to be the market leader in its class.

As ever, in addition to its leading crane engineering, Liebherr is well known as an innovator in production technologies. The most recent example of this was the installation at the Ehingen plant of a new paint system specifically for its heavy crawler cranes. Activated late last year, the new system is the first three-component paint system used at the mobile crane plant and offers significant environmental benefits as well as improved energy efficiency.

Since its introduction Manitowoc’s Variable Position Counterweight (VPC) system— available on their 300 and 650t MLC models—has won strong market support, especially in North America where several of the largest US crane rental companies such as Maxim Crane Works, Bigge Crane & Rigging and All Erection & Crane Rental have acquired multiple units. Indeed, adding to the ten MLC 300s ordered at its ConExpo 2014 launch, All Erection just added two MLC 650s to its huge fleet of Manitowoc heavy crawlers. Further afield MLC 650s have joined the fleets of Tutt Bryant, Australia’s largest crawler crane hirer and Koreas leading crane hirer Shinui Petra.

But Manitowoc is not the only US manufacturer of crawler cranes in this class. Those with a keen eye will have noticed mention of the CC 9600 crawler crane in our table. This is a crane designed and manufactured in Louisiana by Deep South Crane & Rigging, one of the leading heavy lift crane and rigging providers in the South West United States.

Founded in 1968 by Camille Landry, the family-owned and operated business is particularly famous for the line of supersized ‘Versacrane’ lattice boom pedestal cranes it built for its own use. These are highly-credible cranes that were developed in close cooperation with one of the great crane engineers, Dieter Jurgens. By chance in 1989, Camille Landry met Dieter Jurgens who had crossed the Atlantic with Harnischfeger Corp to become chief engineer at the P&H lattice crane plant in Escanaba, Michigan. The two men struck up a fruitful friendship that lasted over 50 years, until the sad passing of Jurgens in 2014. Amongst his numerous patents, Jurgens developed US patent #4,258, 852 granted on March 31, 1981 for an “auxiliary counterweight for mobile cranes”.

It was a variant on the Skyhorse theme. While with Deep South, Jurgens and Landry developed a fleet of pedestal cranes of up to 2,500USt capacity as well as the CC 9600, their only crawler.

Superficially the difference between a 600t and 650t crawler crane might appear marginal but, in fact, there’s a significant gulf in their performance. The sales success of both the Manitowoc MLC 650 and Demag SL 3800 underline this. After some 20 years in production the 600t CC 2800-1 remains in the Demag line but is now heavily outsold by its big brother. Indeed, the SL 3800 has been a runaway success with approximately 100 units sold to date. The SL 3800 has proven especially popular with Europe’s large crane hire companies where its performance on wind turbine erection has won wide praise. The phenomenal success of the SL 3800 must have even surprised the most optimistic at Demag. Multiple units have been purchased by Sarens, Dufour & Aertssen (Belgium), Mammoet (the Netherlands), Weldex (UK), Franz Bracht, Steil, Maxikraft, Neeb & Schuch, and A.M. Kran- Wind (Germany), Nordic Crane Vest (Norway) and Crane Rental Poland.

Crawling around the world

Further afield the SL 3800 has joined the fleets of Bigge, Burkhalter and AmQuip in the US while emerging markets have also given the crane their support. Big crane demand is developing In Latin America. New Demag SL 3800s have been sold to customers in Peru and Chile while in Uruguay Gruas Mar now owns that country’s largest crawler crane in the shape of an XCMG QUY 650. Argentina is a market where FUWA has found success with its 750t QUY 750 via Tecmaco. While the Brazilian boom may have, to some degree, bust, investments continue in the wind energy sector with crane renter I.V. Guindastes recently purchasing a refurbished 2012-model Liebherr LR 1600/2-W wind-version from Ehingen, to add to two similar cranes already in its fleet.

Wind farm erection has made India one of the world’s most important markets for heavy crawler cranes these past 2–3 years. Indian crane buyers have a deserved reputation as being conservative and extraordinarily cost-conscious. While sometimes they are swayed by a low price, they have a degree of comfort in the knowledge that India has blacksmithing ‘fix-it’ facilities on every street corner. However, the Indian crane buyer values globally-established brands, and when it comes to big crawlers the Demag CC 2800-1 remains a prized model with sales of both new and used units in equally-strong demand.

But by no means does Demag have the field to itself. Over several years, Liebherr’s LR 1600/2 has won strong support particularly with the likes of Snethia Erectors and BHEL. As elsewhere in the world, the trend to ever-larger wind turbines has fuelled Indian market demand for 650t class crawlers. Several Demag SL 3800s as well as Sany’s SCC 6500 are now in service on Indian wind farms. Here Amrik Singh & Sons is especially prominent, having purchased seven Sany SCC 6500s during the past 18 months.

However, although India’s largest crane hirer Sanghvi Movers placed a very large order with Terex-Demag for SL 3800s, not for the first time that order was subsequently significantly reduced in scale. Other manufacturers like Grove have had to live with the difficult consequences of such behaviour.

India continues to prove a highly lucrative market for Chinese cranes, including crawlers. Indeed, it is often listed as a top export destination for XCMG, Sany, FUWA and Zoomlion. Amongst the first exports of large Chinese crawler cranes were to India with Zoomlion placing 600t QUY 600s with Essar and Tata’s Mandvi Thermal Power Plant and XCMG selling no less than ten 650t QUY 650s to Reliance.

Demand for this class of crawler crane in the Middle East has been somewhat restrained in recent years. However, one of the region’s leading crane rental providers—Integrated Logistics headquartered in Kuwait—recently added a 650t Demag to its huge crane fleet while XCMG continues to do well in Iran.

Certainly, the Chinese cranes have the benefit of somewhat lower costs, but it’s also clear that the engineers of the market leaders continue to innovate. The performance of the LR 1600/2 with wind turbines has been substantially enhanced by the introduction of the new SL 10 and SL 13 boom systems allowing booms to 153m plus a 12m jib. One customer in Germany used the SL 13 boom to great effect hoisting 63t 2.5Mw turbine hubs to a height of 138m.

Meanwhile the performance of Demag’s SL 3800 can be dramatically increased by installation of the Boom Booster. Employing 3.5m wide sections, this double boom insert increases lift capacities by up to 30% and allows total system lengths to 183m. In addition, Demag recently introduced a PC pedestal version of the 3800 with the first unit joining Sarens large fleet of this model. Compared to the crawler version, the PC-3800-1 offers easier site access and saves on site preparation. It’s available with a pedestal outrigger base of either 12m x 12m or 16m x 16m with significantly increased capacities.

These big cranes of today may have a passing resemblance to their forefathers, but the likeness is skin deep. Today’s big cranes are light years ahead in terms of precision control, operator control and information, serviceability, flexibility of operating equipment, speed and ease of erection and dissembly and transportability.

The story of the crawler crane that began in 1911, particularly at the heavier-end, is bright indeed.