E-Crane explains the basic balance design principles employed on floating cranes and cites successes that prove the effectiveness of floating terminal technology.
The balance crane principle is simple. The “E” in E-Crane stands for equilibrium, a key feature of the parallelogram style boom which provides a direct mechanical link between the stick and the rear counterweight. There are no steel winches or cables in the design.The counterweight continuously balances the total weight of the steel structure along with half of the operational load.As the lifting radius is varied, the change in the load moment is automatically equalised by the moving counterweight. With traditional hoisting machinery, the payload, working tool, and steel construction all have to be lifted, but the E-Crane’s balance compensates for all but half of the payload. Compared to conventional cranes that require as much as 80% of their available energy just to move balance crane the boom, stick, and grab, the balanced crane puts gravity to work, reducing horsepower requirements and power consumption by up to 50% and significantly reducing maintenance and operating costs. This superior balance permits mounting on virtually any type of barge, and according to the manufacturer, even ones without spud poles. There are many benefits, one of which is that the balanced nature helps to minimise tipping when fully loaded. This means less barge movement which results in less friction between the floating terminal and the vessel and more precise and faster grab positioning. There are numerous examples of E-Cranes installed on barges or pontoons, but we will only highlight three of them; Albatros, Seaboard Midema, and Titan.
Albatros by Herbosch-Kiere
Back in 2009, Herbosch-Kiere (part of the group Eiffage) put a new dredger into operation, called the Albatros. The Albatros is a self-propelled spud barge with a 1500B Series E-Dredger installed on it. It has a 29m horizontal reach, 15 Mton lift capacity and an 18m dredging depth. It’s immensely flexible, as the crew only has to raise the spuds and start the engines. There is no need to wait for a tow. The Albatros puts balance to the test day after day. According to the crane operator, even after raising the spud poles at the dredging job and lifting a fully loaded 5.5m3 clamshell bucket to an extended position of 27m outreach above the water, the pontoon tilted by only 20cm. The spud poles are only needed to keep the barge in position in tidal waters. The crane operator also states that the machine is “amazingly quiet.” This can be useful when working closer to shore and near residential areas.
The Albatros is also a “green machine”, operating on a 225kW electric motor, harnessed from the engine used to propel the barge. This means costs for diesel can be kept to a minimum. The Albatros has worked on projects in the port of Ostend in Belgium, Rotterdam and London. At the time of writing, the Albatros is being put into service preparing the seabed for wind turbines in the Swedish part of the Baltic Sea, in close vicinity of the city Karehamn. Before arrival of the wind turbine foundations, the seabed needs to provide a perfectly flat surface. Firstly, 0.5m of the seabed will be removed by the Albatros to provide a solid surface and remove all large boulders. The Albatros has enough power to excavate the hard seabed, creating a perfectly horizontal surface. After the foundations have been installed, they will be ballasted to be able to withstand the powers of the sea and the wind turbine itself. In a preliminary phase, the shafts of the foundations are filled with crude iron ore, which is cast via a funnel using a cable crane. In the next stage, the other compartments are filled with crude iron ore. A layer of heavy quarrystone is then placed on top. To prevent the gravel layer from being washed away, the Albatros will install a quarrystone anti-scour layer out of rubble around the foundations.
Seaboard’s Midema grain terminal in DRC
Another notable floating E-Crane project is the one for Seaboard’s Midema grain terminal in Matadi, Democratic Republic of Congo. Matadi is the furthest inland harbour on the Congo River, and just like many other ports in Africa, there are major port congestion problems. This, combined with the lack of new and reliable dock side equipment, was a major bottleneck in Midema’s grain supply chain. Back in 2008, Seaboard opted for a 1000m2 floating terminal for their new material handling equipment. It is equipped with a 1500 Series E-Crane with an outreach of 35.9m, lift capacity of 13.5 Mton and a 400 Mton per hour unloading capacity. This floating system can unload up to Handymax sized vessels for ship-to-quay or ship-to-ship trans-loading. The crane transfers grain from the ship into two hoppers, and a conveyor transports the grain directly to the silos.
The terminal, called Mama Mobokoli (“caring mother” in one of the local dialects), is a self-sustaining platform complete with electric genset. However, the system can be attached to shore power through a built-in switch gear. It also came equipped with a winching system that allows the platform to shuttle alongside the ship for full access to each of the ship’s holds. The entire platform was erected and tested at the port of Zeebrugge in Belgium, making for a quick and easy installation of the system on-site at the port. From there, a dedicated tow transported the whole platform to its final destination in the DRC where unloading could begin immediately; a big advantage for Seaboard since the logistics of local marine construction would have been very difficult and costly. This journey only took 40 days. Also, the DRC can sometimes be politically unstable. An additional advantage of the floating terminal is that it can be detached from the shore, to travel away from possible vandalisms during these hard times.
New dredging unit: Titan
Remember the “extreme machine” Blockbuster in the port of Rotterdam? This balance crane state-of-the-art machine is a heavily modified E-Crane with an outreach of 63m and a lifting capacity of 50 Mton.This monstrous machine has a height of 30m and tips the scales at 1200 Mtons. The original contractor, PUMA, used the machine from 2011 through 2012 for the construction of a stone dune at the Port of Rotterdam, an important part of the hard sea defense which will protect Maasvlakte 2 from the sea and from extreme “10,000 year” storms. The Blockbuster placed approximately 20,000 individual large concrete blocks into the hard sea defense of Maasvlakte 2. Each block is 2.5 x 2.5 x 2.5 meters and weighs more than 40 Mton. In January 2012, the Blockbuster’s work at the hard sea defense was complete.
However, the Blockbuster will not die a silent death, as it is about to get a second life in the Caspian Sea. The Blockbuster will be renamed, “Titan”. At the time of writing, the Blockbuster is being disassembled and sent back to E-Crane’s workshop for modifications to fit its next job.The cylinders, each weighing about 4 tonnes, have already been removed. Disassembling the counterweight and catwalk platforms will be the next step. The upper part of the Blockbuster will soon start a new journey on a pontoon for SAIPEM, an Italian company and international contractor in oil and gas. The Titan will be used for a dredging operation in the Caspian Sea, close to the shores of Kazakhstan, where pipeline is going to be installed. The Titan will dig a trench where the pipeline is to be placed. Using the Titan allows the mud/dirt to be stored underwater in a stockpile along the trench enough distance away to ensure that the material will not migrate back into the trench. This saves SAIPEM time and money because they will not require transport vessels to store the material while the pipeline is being placed. Once the pipe is installed, the Titan will reclaim the mud/dirt from the underwater stockpile and cover the pipe.The Titan brings a combination of outreach (45 m) and lifting capacity (24.5 Mton) never before achieved by conventional dredgers.
Perfectly balanced floating terminals on the rise
These noteworthy projects are just a few of the examples of how the balance principle passes practical tests in the field. Ports and terminal operators are continuously realising the advantages of such a system. Kinder Morgan recently purchased a brand new 1000 Series E-Crane mounted on a custom barge, for cleaning coal barges at their terminal in New Orleans, USA.A new balanced material handler will also be installed onto a floating terminal in the port of Kazan for the Russian company.Volga Shipping. It will be used for gravel and sand unloading. There will definitely be an increase in floating terminals over the next couple of years as more and more terminal operators become aware of the benefits of the floating bulk handling equipment.
They provide unique benefits that fixed dockside equipment cannot: they are extremely flexible and even self-sustainable. They can easily be detached from the shore when necessary, to avoid congested ports and damage due to severe storms. Combining the benefits of the balance principle and floating terminals makes very cost effective material handling equipment that’s adaptable to any situation. It’s the ideal solution to replace outdated equipment, and even when no land is available, you can expand your operations onto the water and further increase efficiency of your terminal.
Source: World Port Development, April 2013