The incredible bulk

01 Nov 2001

Bulk carrier design rarely warrants more than a passing mention. The ships are often seen as little more than strengthened barges with engines. And clichés such as "sausage factory" are commonly used to describe the production line of yards building them. But nobody could level such accusations at Gypsum Transportation?s new ship Gypsum Centennial nor at its builder Hyundai Mipo Dockyard. The ship features the first commercial application of a new design engine and a potentially revolutionary new unloading system. The builder specialises in one-off ships. The ship was scheduled for delivery to its owner on October 27. At the time of The Motor Ship?s meeting with the owner?s technical representative, in early October, Gypsum Transportation was working on a couple of potential fixtures that would allow the ship to sail to its regular area of deployment in North America with its first fee-paying cargo. This in itself would be a first for Gypsum Transportation, as all its previous vessels have been unavailable for third party hire. Gypsum Centennial?s primary employment will be for Gypsum Transportation?s parent-company United States Gypsum (USG), carrying gypsum rock from its quarries and ports in Nova Scotia, Canada to its production plants on the US east coast. It is effectively a replacement for the 28-year old Gypsum King, which the company plans to retire in 2003. However, Gypsum Transportation is a separately registered company to its parent (which incidentally is undergoing Chapter XI bankruptcy reorganisation relating to its liabilities to asbestos claims), and as such is required to operate independently. This, in turn, means it needs to generate operating revenues, independent of its parent, in order to cover costs. Therefore the ship has also been designed for the carriage of other bulk cargoes that third party cargo owners might want shipped north, such as coal, limestone, hot briquetted iron, sand, grain and phosphate. "This is the first vessel available for third party hire," says John McMillan, technical director for Gypsum Transportation?s technical manager, Beltship Management. "All previous vessels returned to Nova Scotia in ballast." This requirement to carry back cargoes had a significant influence on the vessel design, particularly its unloading system. But it is the area of operation that had the strongest influence. On its hauls between Nova Scotia and the US east coast, Gypsum Centennial can expect to encounter powerful natural influences and at least one man-made one. Nova Scotia?s Bay of Fundy, in which USG?s Hantsport quarry is located, has the largest tidal range in the world, some 12.2m. All the ship?s systems and procedures for loading and unloading need to account for this. On top of this the area?s climate, particularly in winter when it is cold and damp, isn?t entirely favourable to the discharge of gypsum. The cargo discharge system needed to account for this. More on these points later. The man-made influence is from the US regulator. The vessel will operate in a jurisdiction with one of the toughest environmental policies around, policed by the US Environmental Protection Agency (EPA). And as McMillan says: "The EPA is only going to get tougher." It is this point that convinced the operator to build the ship with such a high environmental specification. Most prominent among these specifications is Gypsum Centennial?s smokeless diesel engine. Smokeless Engine Gypsum Centennial has a Sulzer 6RT-flex58T-B two-cycle diesel engine, with a maximum continuous rating of 11,275kW at 93 rev/min. The RT-flex engine features electronic-controlled common-rail fuel injection, which is intended to maintain constant injection pressure, regardless of load, and allow smoke-free operation. It has been described at length in previous issues of The Motor Ship. Aside from the common rail system, the engine is a standard RTA58T-B engine with no change to its internal mechanical and thermal loadings. The ship was initially envisaged to have another engine type, according to McMillan, with the same power and speed. He doesn?t say whether this was a camshaft controlled injection engine, but he does mention that an enquiry was lodged with MAN B&W about its Intelligent Engine. The Danish engine builder responded that it was not ready to deliver what was needed, having only just contracted a pilot installation of its Intelligent Engine on Odfjell?s Bow Cecil. McMillan echoes the natural optimism of Wärtsilä about the preliminary results of the sea trials. "The engine did operate smokelessly throughout the sea trials," he says. "Although the difference was hardly noticeable at high powers, the improvement could clearly be seen at low speeds." The trials involved varying the engine speed from full-ahead to as slow as 12 rev/min. The Hyundai Heavy Industries-built engine was initially run on marine diesel oil before it was switched over to its standard operating heavy fuel oil. This has 3% sulphur content, a specific gravity of 0.996 and 377cSt viscosity at 50?C. McMillan says the monitoring system registered two alarms during the trials and these were unrelated to the engine?s electronic control and common rail system. As it is the pilot installation of such an engine, Wärtsilä has supplied Gypsum Transportation with an extended warranty that would involve reverting the engine to camshaft operation if necessary. McMillan says this "will never happen" but its provision gave the group added peace of mind. The warranty also involves Sulzer engineers sailing with the ship for up to three months, so that they can apply their expertise and learn about the engine for service purposes, he says. Wärtsilä also agreed that its engineers would supply structured training while they were on site at the shipyard in Ulsan. McMillan says the ship?s chief engineer and his relief, the superintendent, the electrician and the second engineer spent five days on a training course at Wärtsilä?s Winterthur factory in Switzerland. The course paid particular attention to the RT-flex system. McMillan adds that the first four went to the shipyard much earlier than would normally be expected with a conventional engine. McMillan?s confidence in the engine is such that he believes that over time Gypsum Transportation will accrue significant benefits through the absence of any camshaft related timing issues: "We will always have peak performance and maximum efficiency with electronic control," he says. His confidence is buoyed by the engine?s high level of redundancy. He says solenoids allow the isolation of a particular cylinder, allowing its removal while the engine is in operation. He adds that there is a duplication of lines from the four fuel pumps to the common rail, meaning if one fails the engine can still operate. These fuel pumps, which are modified from those used on the four-stroke Sulzer ZA40 engine, are set in a vee-arrangement and operated by multiple lobe cams. They use suction control to maintain the common-rail pressure at the desired value (which can be as high as 1,000 bar). If one of the pumps fails McMillan says the engine can still operate at 100% and if two go down, the engine can still achieve 75% power. The crankshaft driven servo system consists of three servos. The servo line is duplicated and if one of the servos fails, or is removed for maintenance, the engine can still operate at 75% power. Real-time data from the engine performance is monitored via the Wärtsilä Engine Control System (WECS) and fed to onboard engineers. Through a Praxis Automation computer-based automation, control, monitoring and alarm system, they can control and monitor main and auxiliary fluid and electrical systems. Environmental basis Gypsum Transportation hasn?t stopped at the engine when it comes to its commitment to the environment. In fact, the specification of the ship is such that the company, which is going through ISO14001 accreditation at the moment, plans to base its entire environmental procedures on the Gypsum Centennial, says McMillan. The ship is completely double-hulled even back past the bunker tanks, so in the event of a collision or grounding, the risk of environmental damage is lessened. It features a water-lubricated Thordon propeller-shaft bearing (so any seal failure won?t result in oil pollution). There is monitoring of refrigerated spaces, so any leakage can instantly be picked-up and rectified. And the ship has the latest Alfa Laval SU500 fuel purifier, which reduces sludge. McMillan anticipates that any sludge produced will normally be discharged at reception facilities in Jacksonville, Florida. The vessel is built and classed to the requirements of Lloyd?s Register of Shipping. The owner has voluntarily sought to have LR?s Environmental Protection (EP) notation. The option of a NOx scrubber was considered, but ultimately rejected on the basis of its cost (close to $1m). "Backfitting remains an option," says McMillan. The environment is even a big consideration during loading and unloading. The vessel uses a dust suppression system that involves spraying a surfactant onto the cargo. The telescopic boom is enclosed with a lightweight cover and every effort is made to channel the cargo into its receiving hopper ashore, by dropping it through a funnel at the end of the conveyor. Unloading system In the climate in which Gypsum Centennial operates, the gypsum cargo has huge potential to bridge across the hog-backs in the holds of conventional gravity self-unloading ships. Traditionally, the solution has been to employ a combination of vibrators and a 50? slope on the hog-backs to break any bridges that form and shake the cargo down through the gates onto the conveyor belt below the cargo hold. Above all else, the requirement for a 50? slope on the hog-backs means they considerably eat into the cargo capacity of the hold. This and other factors led the owner to search for different solutions. What it settled on was the BMH Nordström designed system that features an innovative "moving hole" feeder at the bottom of the cargo hold. It is the first installation of such a system and the owner selected it only after travelling to Canada to see a full-scale mock-up in use. As the name implies, a gate moves sequentially over a number of "holes" above a conveyor on each side of the ship. When the hole fills up, the gate moves on to the next hole and so on while the contents of the previous hole are dropped onto the conveyor below. Any cargo trying to bridge on top of the gate is prevented from doing so by a moving scraper plate on top of the gate. This pushes cargo back into the hole. To complement the moving hole feeder, Gypsum Transportation specified Sigma CSF glass-flake coating for the cargo holds. This non-stick coating helps the cargo slide down the hog-back toward the moving hole at the bottom of the hold. McMillan says the combination of moving hole feeder and glass-flake paint has allowed the angle of the hog back to be reduced to 45?, thus significantly increasing hold capacity. The width of the conveyor belts, at 2m, means the belts can operate at relatively slow speeds, while still allowing an unloading speed of 3,000t/h. This is advantageous in terms of maintenance, says McMillan (in the same way that slower engine speeds are advantageous). The width also means McMillan isn?t anticipating any cargo falling over the side of the belt, even when unloading at 3,000t/h, which means a need to clean-up is removed. The two conveyors run from the foremost hold and discharge their load on two vertical belt pick-ups behind the rearmost hold (number four). Where the conveyor passes through bulkheads, BMH Nordström watertight bulkhead doors are fitted. To increase the capacity of the fourth hold, a third conveyor and vertical pick-up system is installed to service this hold only. The vertical pick-ups discharge the cargo into a hopper above a telescopic boom. The boom allows discharge of cargo at distances of 23.9 to 60.1m from the side of the ship. It is the largest of its kind. The boom can swing 90? port and starboard and has a maximum loft of 18? (above this the gypsum would start sliding back). The flexibility this gives is helpful to the owner in it securing third party charters involving discharge in ports it is unfamiliar with, says McMillan. Loading up Before it can discharge cargo, the ship obviously needs to load its cargo. In somewhere such as Hantsport, where the tidal range is large, loading is a meticulously planned exercise. McMillan says there is a three hour window, up to the point of high tide, during which the ship can come alongside and load. The ship enters port with its hatch covers already open. These are MacGregor?s rolling type hatches ? a type dictated by the restricted height loading arm at Hantsport. The ship can have a maximum draught of 9.75m at any time before and during loading operation. This, coupled to the restricted loading window available at Hantsport, means the vessel is fitted with a sophisticated free-flow drop out ballast system that can fully deballast the ship in 45 minutes. Cargo is loaded at a rate of 20,000t/h and throughout the operation an under clearance of just 0.3m is maintained. The owner works closely with Fundy Gypsum (the USG subsidiary that operates the quarry) on a loading plan. A system of lights on the vessel?s superstructure indicate the list of the vessel and enables those loading the ship to trim continuously. Throughout the operation, the engine is left running. This enables a quick getaway if there is any sort of problem. The speed at which the ship can depart is increased by the fitting of a controllable pitch propeller, a high-lift Becker rudder and a 1,100kW bow thruster. The bow thruster working in combination with the controllable pitch propeller (set at zero pitch) and the Becker rudder (set at 45?), allows the ship to move out from its berth sideways without tug assistance. McMillan says that to be doubly sure the ship can move out as required, a blank tunnel has been left at the stern for future outfitting with a thruster if the combination of controllable pitch propeller and Becker rudder fails to provide the manoeuvrability required at the stern. He is confident from the sea trial results and previous experience with Becker rudders at Torvald Klaveness that this won?t be necessary. He adds that the Becker rudder will also be advantageous in ports with narrow channels, such as Little Narrows. Safety first The ship incorporates conservative scantlings and is therefore possibly slightly heavier than it needs to be, admits McMillan. The payback though is greater safety and a longer lifespan. It was designed using LR?s ShipRight structural design procedures and is the product of initial plans by Ron Williamson, lead naval architect at CR Cushing. The ship is fitted with Raytheon Marine?s one-person integrated bridge system. "The owner has no intention of running a one person bridge, but liked what that gave him [in terms of safety]," says McMillan. It also has closed circuit television throughout, broadcasting images of the deck, cargo area, engine room and other critical areas to screens on the bridge and in the engine control room via fibre-optic cabling. The engine control room is on a working deck, which features various offices. Crew accommodation has been fitted out to best western standards by the shipyard, according to McMillan. It is wired for the installation of satellite television ? the owner has decided to do this at a later date having been given an $80,000 credit by the shipyard for not installing it in Korea. There is a large owner?s complex. This is available for the use of USG directors or any creditable person wishing to observe the operation of the ship, says McMillan. On delivery, Gypsum Centennial will sail under the Bermudan flag. It is four months late. Gypsum Transportation had allowed two months, because of the high specification required. The remainder of the delay is due to an explosion experienced in the hydraulic room during the building of the ship. This tragically killed six dockyard workers. Gypsum hopes this will be the last of the ship?s bad luck and it can get a full 30 years service from its new high specification bulker.

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