Enköping is a small Swedish town 60 kilometres west of Stockholm where a company called Nordströms started delivering elevated cable transport systems for industrial purposes back in the 1880s. The systems were designed for long distance operations. This materials-handling background made the step into shipping and the handling of bulk materials natural. Nordströms is a well-known name of MacGREGOR Bulk (formerly BMH Marine), a division within the MacGREGOR Group, specialising in dry bulk handling solutions. This is now MacGREGOR Bulk, specialising in various types of selfunloaders. In 1947 they delivered the first totally enclosed selfloading/unloading cement carrier with highly automated cargo handling gear. Over the past 60 years, Nordströms systems have been installed into more than 90 cement carriers sized between 500 and 40,000 dwt. In addition, nine floating cement terminals have a Nordströms system installed.

“Cement carriers are very special ships where we can offer a unique and very well-documented competence base on what is proven technology, but not a technology which can be easily utilised unless you have the competence and experience,” says Jan Karlsson, Selfunloading Systems Director of MacGREGOR Bulk.
“Cement,” he continues, “is often loaded by blow pumps that actually blow the cement into the cargo holds. There are also fluidised tank bottoms to ensure air flow for the process. Cement behaves as a fluid when mixed with air. After loading a vessel the ship will have to wait for the cement to settle before leaving port to avoid stability problems.
“The average age of a cement ship is actually some 25 years and the total fleet consists of some 350 to 400 vessels, both converted bulkers and newbuildings. With global construction of newbuildings on shore running high, the demand for cement is consequently high. The global construction boom is not going to slow much over the next years, so we see the demand for cement carriers to be rather stable at a steady increase also in the future,” says Karlsson.
“The fleet is rather old and we are expecting that a replacement boom will come soon. We deliver all the necessary equipment from the fluidised bottoms for reclaiming cement in holds, the vertical and horizontal screw conveyors for distributing cement to and from the holds, the blow pumps for pneumatic conveying from ship to silo, the bulk discharge boom for mechanical discharge from ship to shore as well as the electrical control system for automatic control of the process and systems,” continues Karlsson.
Another product from MacGREGOR Bulk in Enköping is the gravity type selfunloading system. It works as follows: “Discharge is done through hydraulically operated gates, either basket gates or ‘Moving Hole’ feeders, fitted to the outlet hoppers in the bottom of the cargo hold, onto the longitudinal hold conveyors located on the tank top level.
“The hold conveyors incline in aft part of the cargo holds and discharge the material onto the cross conveyors. From the cross conveyors the material is transferred to the C-conveyor located on the ship’s centre line, just forward of the engine room bulkhead – or in front of the forward hold at the bow of the vessel. The C-conveyor elevates the material to main deck and discharges onto a slewable and hoistable boom conveyor.
“The boom conveyor is equipped with one continuous belt with a telescopic end for easy positioning and transferring of the material to the receiving arrangement ashore. The discharge capacity can be up to 6,000 metric tonnes per hour. The boom conveyor has a maximum reach of some 76 metres.”
For safety of the vessels and crew, MacGREGOR has also developed the Watertight Bulkhead Door designed to minimise water leakage though the conveyor tunnels between the cargo holds in case of emergency. All doors are to be closed and secured when the ship is at sea.
Jan Karlsson has a great amount of technology to describe, including new offshore barge based terminals for vessel discharge to Cape size vessels, to the bulk handling system for cement – consisting of the cement tanks, compressors for transport air, control systems, valves and dust handling systems.
The story of M/S Melvin H Baker is unique: “On 12 January 1997, the Melvin H Baker completed her 1,797th voyage, a remarkable achievement for a 17,939 dwt bulk carrier in international blue water trade. The Baker, now approaching 50 years of age, looks as good as new, especially her engine room and selfunloading equipment,” says Skaarup Shipping.
“The Melvin H Baker was built by the German yard AG Weser and delivered to her owners in 1957. Named after the founder of the National Gypsum Company, she was designed by Ole Skaarup whose company, Ocean Wave Shipping Corporation, now owns her. Incorporated within her hull is a Nordströms selfunloading system which provides significant efficiencies and cost savings by rapidly unloading her cargo through a stern discharge shuttle conveyor.
“Through more than 40 years’ service and 1,797 voyages, she has carried in excess of 28,620,893 million tonnes of cargo from Nova Scotia to various US East Coast ports. She has travelled a total distance of 2,869,236 nautical miles. The figures are now ten years old and she is still in the same trade.

Date: 04 February 2008