Shipyard Kooiman Delivers Push Boat for Reliable Nonstop Operation
At Shipyard Kooiman, a new 40 metre push boat named Veerhaven III Waterbuffel was christened on 20 March 2012. The Zwijndrecht-based shipyard has previously built two push boats for the same ship owner Veerhaven, a subsidiary of the German ThyssenKrupp Group. The fleet of push boats and barges, filled with coal or iron ore, transport the goods from Rotterdam, IJmuiden, Flushing, Antwerp or Ghent to the steelmill in Duisburg, Germany. As the storage capacity at the steel mill is minimal, the push boats and barges are used for just-in-time delivery of the necessary ingredients to make steel at the blast furnace.
Just like the steelmaking process, the process of supplying iron ore and coal should run like a clockwork, in a continuous uninterrupted flow. That is why the fleet of push boats is designed and built with one major goal in mind: nonstop service. Downtime for equipment failure and maintenance is reduced to an absolute minimum.
When arriving in Duisburg, typically the push boat will leave four or six fully loaded barges at the terminal, and start the downstream leg straight away with four or six empty barges. In Rotterdam, the empty barges are quickly swapped for full barges and the upstream trip begins. In a year, these ships clock over 8,000 running hours. Less than 10% of the time is spent at standstill. A roundtrip typically takes 43 hours.
The water levels of the Rhine dictate part of the operations. In times of shallow water, more push boats are needed to transport the 60,000 to 80,000 tons of dry bulk which are shipped up the river each day. That is why maintenance periods are planned in times of higher water levels. About once every two years, each ship in the fleet goes back to the builder’s shipyard for an intensive two-week maintenance period. Project manager Arjan van der Zegen de Beer explains: “Apart from some propeller damage in shallow water, none of our vessels for Veerhaven has had to interrupt their operations because of mechanical failures.”
While Veerhaven III features three completely separate engines and shaftlines, she can run fully loaded with six barges at the required speed with two engines only. The three rudders each feature an independent steering gear. The rudders can be operated individually, which can be an advantage in certain manoeuvring situations, or simultaneously. The hydraulic powerpacks for the steering gear are normally powered by the auxiliary gensets, but the emergency generator also has enough power to supply the steering gear as well. To optimise serviceability, and thus minimise downtime, storage tanks are installed for the main engines’ internal cooling water. After maintenance work on the engine, the cooling water can be pumped back into the engine with a dedicated pump.
Bunkering on the go
Even for bunkering or crew changes, the Veerhaven III will keep on sailing, albeit at a slightly more sedate pace. A bunkering ship will come alongside and travel with the Veerhaven III until the bunkering operation is complete. By company standard, this procedure is preferably executed during daylight hours. The full crew changes every Wednesday at noon, so the location for this procedure is not always the same. When the Veerhaven III is ‘en route’ at that time, the new crew will drive a rental car to a point slightly ahead of its position. During a few back-and-forth trips with the Veerhaven III’s tender between the moving ship and the rental car, the entire crew is changed, after which the previous crew can return home with the rental car. To execute this procedure, the tender boat is launched with a painter line alongside the Veerhaven III. When its engine is running, the painter line goes slack and it is disconnected from the mother ship. The back- and-forth ferrying of the crew can then begin. Supplies are usually delivered to one of the ports and taken onboard when the barges are exchanged.
When you pack over 4,000 kW of propulsion power in a 40 metre ship with a very shallow draught, noise and vibration control becomes essential to ensure the living conditions on board. For this reason, the entire accommodation is mounted on 21 tailor-made air springs from Loggers. The compressed air in the springs has a regulated supply from the 8-bar working air from the ship. This keeps the deckhouse at the middle of the air springs’ four centimetre travel, to ensure proper vibration isolation independent of the load in the deckhouse. In addition to the air springs, hydraulic shock absorbers are mounted in both the horizontal and vertical direction to ensure the damping of the movement. To prevent the deckhouse from moving in the event of a collision, a small gap separates the flexible structure from steel contact points welded to the deck on all sides.
All pipes passing from the lower deck to the flexible deckhouse have a flexible part thanks to the connection, such as a small length of flexible hose or a rubber bellow. In the engine room a lot of attention was paid to the mounting of the exhaust systems. The noise dampers are mounted with anti-vibration mounted on a stiff frame, which together with the entire funnel, is itself flexibly mounted on the deck. The combination of noise reducing measures has resulted in noise levels of only 45 to 50 dB(A) in the accommodation.
A modification compared to the Veerhaven X, is the change from two electrically-driven bow channel thrusters to two diesel-driven channel thrusters from Verhaar Omega. Even on a single engine, without barges attached, the idling speed of the Veerhaven III is seven kilometres per hour. This makes it difficult to manoeuvre during the coupling or uncoupling of the barges. The new bow thrusters also feature a forward- facing and an aft-facing channel, which allow for more precise maneuvering without the main engines. The number of auxiliary generators has been reduced from four to two, keeping the total amount of diesel engines the same (eight, including the harbour generator).
The three main engines are of the 8M20 type from MaK. The fixed pitch propellers are placed in nozzles, mounted in deep recesses in the hull. In way of the propeller, these tunnels are about 40 centimetres above the waterline, unavoidable if you fit 2,050 millimetre propellers in a ship with a draught of only 1,700 millimetres. At the stern these tunnels slope back down to below the waterline, to allow the propellers to fill the tunnels with water when sailing astern or when performing the crash-stop test. To avoid any chance of oil pollution – which would necessitate a trip to the drydock – the shaft bearings are water-lubricated.
As the river water, due to the low draft, contains a lot of ‘stirred up’ silica, this vessel sails with a Maprom-designed closed-loop system. In normal operation the fresh water is continuously circulated between a buffertank and the bearings. The water goes in at the inboard shaft seal and is led back inboard through the V-brackets near the propeller. The water-lubricated bearings with closed-loop system from Maprom have a very long service life and have been successfully used since the mid 1960s. In a case of aft seal problems this vessel does not have to return to a drydock because the system can operate for extended time with the dirty riverwater the vessel is sailing in. One of the ships in the fleet, Veerhaven V, has clocked over 230,000 running hours on a single set of water-lubricated bearings.
Two of the bearing sets on Veerhaven III are demountable rubber stave bearings, which means that the bearing can be replaced without pulling the shaft. In addition to the inboard and outboard shaft seals (type GS) and the forward and aft hard-coated tailshaft liners, Maprom also delivered the fendering for the pushbow, which consists of tough rubber extruded pads with high abrasion resistance. The pads are vulcanised to the steel plating for secure fastening. The corner fenders are of a particular type for lower friction.
The Veerhaven III is not built under class and as such there is no ‘Unmanned Machinery Space’ notation, but nevertheless the ship is equipped with an advanced alarm and monitoring system from SAM Electronics with over 200 I/Os.
The shipyard’s in-house electrical contractor, Technisch Bureau Mous, installed the MOS 2200 system, which is more commonly found on oceangoing ships. All sensors are connected to a central processor in the switchboard room.
Through two redundant networks, the data is available for read-out either on the two PCs in the switchboard room or through one of the four LCD panels, which are located in the messroom, in the engineer’s cabin, in the engine room and in the wheelhouse. Through mimics, the crew has access to the parameters of the main engines, ballast tanks, bilges and so on. The system also includes a dead-man alarm for the engine room. Veerhaven III is the third ship for which ship owner Veerhaven opted for the MOS 2200 system from SAM Electronics.
The crew normally consists of seven persons, housed in single cabins with adjoining shower rooms. Each bed holds two mattresses, so the crew can change the mattress when boarding at the beginning of a two-week working period. A spare cabin is sometimes used by an additional maintenance mechanic. The upper deck features a galley and a spacious dining room/lounge. A small fitness room is arranged on the main deck. The wheelhouse has floor- to-ceiling windows for optimal visibility.
The navigation and communication equipment, supplied by Alphatron, include two river radars with a radar-overlay system, an electronic chart system, a river pilot system and a CCTV system. While some of the previous vessels have featured a system to automatically control the speed based on a given time of arrival, this is not installed on the Veerhaven III. The reason is that an experienced captain can better judge the appropriate speed based on E.T.A., traffic, local complexity of the waterway, etc. than a computer programme. Instead, the Veerhaven III is equipped with a Mirar Fuel Control system from Electro Service Urk (ESU).
This system, developed together with Veerhaven’s technical department and first introduced on the Veerhaven XI, takes control of the propulsion control levers to regulate the rpms of the main engines based on the pre-set allowed fuel consumption. For example, when the ship enters a section with shallow water, the engines will automatically be throttled down to prevent inefficient operation. The fuel consumption per hour (not per kilometre) will be kept constant. The system can always be easily overridden by manipulating the propulsion control levers.
Inherent to the cargo shipped (iron ore and coal) is a lot of dust in the air. That is why all the air inlets are provided with filters, which are basically linen bags through which the incoming air has to pass. This not only keeps the interior climate enjoyable, it is also important for the combustion air for the diesel engines onboard. While there is no fixed fire extinguishing system for the engine room – as it is not required – the switchboards are provided with a self-activating fire extinguishing system from Polmai.
The Veerhaven III is equipped with movable navigation light masts for the barges it has to push. A power cable on a reel is provided for these masts. Also, a pneumatic connection is provided, as some of the push barges are equipped with bow rudders, driven by air pressure.
With so much emphasis on reliability, new technology generally needs to have a proven track record before it makes it on one of the Veerhaven push boats. The advantage of this ship owner is that they have a very reliable data set, with several almost identical ships, sailing the same route, with identical cargoes. ThyssenKrupp Veerhaven is currently investigating ways to reduce the fuel consumption and emissions by using a waste heat recovery system in the exhausts. Dual-fuel installations are also looked at for the longer term.