A fleet of 13 Manitowoc crawler cranes at a specialized fabrication yard in Lobito, on the coast of Angola, represent the embodiment of engineering progress at Manitowoc’s crawler crane brand over the past 45 years. The cranes showcase more than 45 years of Manitowoc engineering, with the oldest model dating back to 1967 and the newest built in 2011.
The cranes are a permanent fixture at the yard, and work 24 hours a day, six days a week. They lift loads of up to 550 t to build structures and lift various equipment for the assembly of oil platforms and other underwater/ offshore infrastructure.
Although the first crane at the facility dates from 1967, it was purchased as a used machine, as part of the first deliveries that were sent to the site in 1998. All of the cranes are owned by yard operator Sonamet, a joint venture between Subsea 7, a seabed-to-surface engineering, construction and services contractor to the off-shore energy industry worldwide, and Sonangol, a leading hydrocarbon company based in Angola.
Alexander Arsie, operations, yards and assets manager at Subsea 7, says the variety of cranes provide the versatility and strength needed to meet the differing lifting tasks at the site.
“We fabricate a lot of different and very large structures so we need adaptable machines that can be set up quickly and perform effectively,” he says. “The cranes are challenged to work round the clock on all manner of lifts. They adapt well to the work. The older machines are put through their paces and manage to keep up with their younger, more modern colleagues.”
The oldest crawler crane on site is a Manitowoc 4000 WV and it works alongside one of the company’s newest models, a Manitowoc 18000 built in 2011. The 18000 is fitted with the MAX-ER capacity-enhancing attachment that increases its capacity to 750 t, making it the most powerful crane on site. The smallest crawler crane is a Manitowoc 5500, built in 2006, which offers a 55 t capacity.
The cranes are building and moving huge sections of infrastructure used in shallow and deep water projects. They are positioned along a fabrication line that builds riser towers, suction anchors, piles, spoolbases and off-shore oil rigs. Sonamet regularly uses the cranes in tandem or in combinations of up to four to carry out the largest lifts.
One of the biggest lifts to date at the yard took place in August this year. Manitowoc’s 18000 and 16000, along with a third support crane, lifted the main deck from an off-shore rig weighing 550 t.
Conditions for the cranes are tough, with the coastal location increasing the potential for rust buildup and the entire
80 hectare site is almost completely covered in sand. On-site engineers, who were trained by Manitowoc Crane Care, perform routine maintenance and regular checks to ensure the sustained performance and longevity of the cranes.
Some of the older Manitowoc cranes were shipped to Sonamet Lobito from other yards in Gabon and Nigeria, also operated by Subsea 7. Newer models were shipped to the African country direct from Manitowoc’s facility in Wisconsin, US.
The cranes are working with a range of boom lengths, most of which are at their maximum. The 18000 has the longest configuration, working with a 90 m boom and 30 m fixed jib. Many of the cranes were supplied with different hook options for handling the various loads.
The full list of Manitowoc cranes working at the yard includes an 18000, a 16000, two 12000s, a 5500, three 4100VWs, three 4000Ws, a 4100W and a 3900WV.
More than 1,600 people work at the Sonamet Lobito yard. The advanced facility boasts workshops, offices and enough production capacity to handle 2.5 million man hours per year, making it by far the largest yard of its type in Angola.