Feature 4
system, which provides maintenance-
free operation and an improved piping
arrangement, since branching pipes are
eliminated altogether, which also simplifies Boom in bulk handling cranes
the piping arrangement, saving space
onboard the vessel. The bulk carrier boom has recently resulted in major orders for Macgregor.
Cement is loaded into the hoppers During the first half of 2007, the company secured cargo handling crane orders
pneumatically by means of compressed for 74 bulk carriers in China and India, with deliveries to continue into 2011.
air provided by compressors onshore. To The supplier says the Chinese market has been the most active and counts
maximise the net cargo volume the filling for a total of 62 ships at five different shipyards. Main products are standard
line to each compartment is split into two or GLB-type cranes with a 30tonne to 36tonne SWL capacity. In the second
more branches before entering the hopper, quarter of 2007 alone, the company received 276 GLB-crane orders for bulk
thus providing several drop points in each carriers with a total value of approximately €75m. A major order, for a pair of
compartment. Transport air is evacuated, GLB cranes apiece for 27 Yangzijiang Shipyard-built 7600dwt bulk carriers was
from the compartments being filled. announced in august.
Dust is separated and conveyed back to a More crane orders were received in the autumn. Ten 56,000dwt bulk
compartment. carriers on order at Hyundai Mipo Dockyard for E Rickmers of Germany will
When unloading, the control system each feature four GLB 3026-2 cranes. Towards the end of 2007 the company
activates the aeration system in the selected confirmed contracts for 390 cranes in all with a total value of close to €140
compartments and starts the blow pump million. The cranes are destined for 101 ships on order in China and South
system. The air supplied by the blowers Korea, comprising 80 bulk carriers, 14 general cargo ships, and 7 container
passes through the fabric of the aeration feeder ships. The cranes are manufactured by Macgregor’s manufacturing
panels and fluidises the cement which will partners in these countries.
start flowing by gravity towards the outlet The strong demand for bulk carriers, combined with the phase-out of single-
at the lowest point of the hopper floor. The hull tankers, has resulted in an increasing amount of conversion projects of
cement is discharged into the blow pump tankers to bulk carriers. The company has also received several enquiries for
in batches of approximately 3m
3
which converting tankers to FPso vessels. Macgregor’s scope of delivery includes
conveys it to the rig pneumatically. This is design, key components, steel structure and installation supervision of new
a cyclic operation. The compressed air for hatch covers.
pneumatic conveying is supplied by the ‘At the moment we have about 30 projects on order, including mostly
onboard transport air compressors. Only single-hull tankers but also double-hull tankers,’ says Pertti Vilhonen, sales
the blow pumps are pressurised. manager from Macgregor.
In a case study, a Vik Sandvik VS491- The company has a dedicated, special unit to prosecute this task. The
type anchor handling vessel was originally conversion projects vary from 30,000dwt to 300,000dwt ships, with drydockings
designed with conventional bulk tanks with taking four to seven months depending on a ship’s size.
four 75m
3
tanks each, giving a total capacity The same specialist team carried out about 400 conversion projects in
of 300m
3
. It was decided to replace the relation to the URS30 regulation changes a few years ago, raising the strength
conventional system with the high volume standard of securing devices and stoppers for steel hatch covers and their
Bulk Handling System, which resulted in an cargo hold openings in the forward part of the ship issued by the International
increased capacity to about 500m
3
. NA Association of Classification Societies (IACS).
Detail, MacGregor’s new high volume bulk
handling system.
The Naval Architect February 2008 91
NA Feb 08 - p90+
91.indd 91 05/02/2008 09:53:57
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