In May 2007 Hermann Buss GmbH & Cie KG and Neptun-Stahlkonstruktions GmbH concluded a contract for design of Neptun-Stahlkonstruktions[ds_preview] GmbH to develop and design a Multi Purpose Carrier with approx. 30,000 tdw, going to meet various demands for transporting a wide range of goods in a most efficient way. The technical idea of such vessel was developed by members of Reederei Buss/Leer and implemented together with Warnow Schiffahrtskontor/Rostock.
Initially 10 shipbuilding contracts were signed with the Chinese Zhejiang Ouhua Shipbuilding Co. Ltd. in August 2007.
Meanwhile 7 of a series of 14 ships have been delivered taking advantage from cooperation with Marlow Company. All ships are managed by REIDER Shipping /Netherlands and MARLOW Shipmanagement / Germany. The Rostock-based engineering office Neptun-Stahlkonstruktions GmbH was already well established as transmission link between Reederei Buss and Ouhua Shipbuilding Co. by developing and introducing designs for Container ships with capacities in the range from 1200 TEU up to 5300 TEU.
Development history
Within 12 months the design consortium leader Neptun – Stahlkonstruktions GmbH and its main partners NE (Rostock), WIG (Wismar) and IMTECH worked out a detailed TRIBON 3D-model enabling the TRIBON – linked yard to start the series.
The first delivery took place at beginning of November 2009 with Hull no. 551 – M/V ‘Lisbon Trader’. Further 6 vessels have been delivered until end of August 2010.
For all the delivered vessels time charters have been fixed by GB Shipping / Leer.
Steel structure
The ship’s body was designed to ensure sufficient fatigue strength over a lifespan of 25 years assumed a North Atlantic sea spectra.
Very impressive is the hatch coaming exterior which leads the huge hatch cover loads to the ship’s structure. Elliptical outcuts allow passage to the inner region between the transversal coamings to reach the cargo hold access ducts, the crane cabins, the reefer sockets or power pack rooms and deck stores. The steel structure is reinforced to allow the whole range of jumping loads. Holds 3+5 or 1+3 or 2+4 or 1+3+5 can be empty while the remaining ones are loaded.
Tween decks
The rectangular Cargo holds Nos. 2-4, which are identically sized (30.4 m length, 24.4 m breadth) can be equipped with tween deck sets either at lower or higher level throughout the hold.
Since the span of 24.4 m and the demand for loads of 4 t/m² would require ultra-heavy tween deck panels, Owner, Neptunstahl and Cargotec (MacGregor) decided to divide the panels at centre line and support them by movable foundation racks. Each of the three tween deck sets consists of:
• 10 uniform panels, distributed in 5 PS. and 5 SB. -panels à 6,032 x 12,133 mm
• 15 racks, assembled to either double tier to form the lower or triple tier to form the upper centre resting line; equipped with standard container corners, internal ladders, top plating for area load of 4 t/m², stowage boxes for lashing parts etc.
The unitized racks are identical and can be stacked and secured similar to 20’-containers, even with 4’ breadth only. Each cargo hold (2–4) bulkhead is fitted with flush mounted tiltable consoles for the additional support of the tween deck panels. The racks, once assembled, allow longitudinal and vertical passage of stevedores.
The panels and their respective racks can be laid out for part coverage only. In this case they are fixed by the tiltable console elements in the aft bulkheads each and internally to each other. Also one cargo hold side only can be covered, if found advantageous. Movable railings to the open cargo hold spaces provide the necessary safety. Some ships of the series will receive modified panels to provide an additional function which allows the use as vertical separation bulkheads as well. This is very suitable to carry small partitions of bulk, clearly separated from other cargo. The Panels have sliding pads (right) screwed on the side plates to ease the movement alongside the cargo hold walls.
Stowage of non-active tween decks
All 30 Panels can easily be piled up in front of the deckshouse instead of deck’s containers. The racks can be stowed in cargo hold no. 5 in lowest positions between stepped tanks, forming a continuous top platform for stowage of break bulk up to 4 t/m² evenly distributed load. One modified rack is usable as working platform, handled by the board crane. For alternative stowage all cargo holds have sufficient lashing points in their side walls to lash racks or panels in vicinity of their active locations intended.
Movable barriers
Since the foundation racks are designed with a high opening degree they can normally withstand all shifting impacts from non-cohesive bulk cargo caused by ship’s heeling. To protect the foundation racks against break bulk impact movable barriers can be provided. These barriers can be fixed at both sides of the racks on double bottom by standard twistlocks and can resist transversal cargo exposure. Furthermore they allow easy stowage and lashing of bundled cargoes and steel coils.
Cargo hold access
The double bottom and both tween deck levels can be accessed from both sides of the cargo holds acc. Australian AMSA rules by means of protected access ducts.
Area loads, stack loads
Area loads
• load on tank top in cargo holds: 20.0 t/m²
• load on tank steps in cargo hold no. 5:12.0 t/m²
• load on Tween Deck panels in cargo holds nos. 2-4 : 4.0 t/m²
• load on Tween deck racks, when not active and stowed completely in cargo hold 5 : 4.0 t/m²
• load on whole weather deck acc. ILLC, but not below 4.0 t/m²
• Cargo hold surrounding walls sufficiently reinforced by special stringer to withstand horizontal forces caused by steel coils with 1.2 m height, 2.5 m diameter and 45 tons weight.
Stack loads
• Tank top and side walls are locally reinforced for stack weights of 150 tons (5 x 30 tons) for 20’/40’ stacks each by means of pressure/tension elements.
• Hatch covers are locally reinforced for 20’/40’-container stack weights as follows:
• Hatch No. 1 in 2 tiers: 28/56 tons Hatch No. 2-5 in 3 tiers: 60/90 tons
• Weather deck locally reinforced in front of deckshouse for 70 tons stack weight for TEU or alternative stowage of tween deck panels (12,133 x 6,032) in 15 tiers: 315 tons stack weight
Axle loads
Cargo Hold inner bottoms, weather deck hatch covers incl. hinge extensions and connection plating between are locally reinforced for the possibility to run with fork lift trucks alongside the 120 m long levelled cargo area.
Cargo transport capability
General
The MPC 30 is tailor-made for the transport of spacious project cargo, numerous general cargoes in palletized or bundled condition, steel coils, paper reels, ordinary bulk cargoes like grain, iron ore and coal and special bulk cargoes, subject to IMSBC-code.
All protruding weld seams are grind to ensure smooth wall surfaces. All pockets and lashing eyes in walls and on double bottom are flush mounted.
Dangerous Goods acc. GL class DG
(SOLAS Chapter II-2, Reg. 19)
Dangerous goods of the classes 1.1-1.6, 2.1, 3, 6.1 and 8 can be carried in form of closed freight containers in cargo holds Nos. 1-5 acc. GL’s class marks DG and the IMDG-Code and on weather deck above the respective cargo holds accordingly.
Dangerous Goods acc. GL class DBC (Bulk Code)
Bulk cargoes of classes A (liquefy cargo), B (chemical hazards) or C can be loaded according IMO resolution MSC.268(85) – adopted 2008-12-04 – International Maritime Solid Bulk Cargoes (IMSBC) Code in Cargo holds 1–4, restricted by the List of selected cargoes, approved by the Germanischer Lloyd.
Dangerous Bulk cargoes of Classes A and B which are also covered by the IMDG code and can be transported in correspondence with the GL class mark DBC.
The Transport of Dangerous Goods of the classes 4.1, 4.2, 4.3, 5.1, 9 and other materials in bulk, which may cause hazards (MHB) is possible in Cargo Hold No. 1–4.
Load distribution plates for project
cargoes
To fit into standard container sockets on the hatch covers or on double bottom the ship has two types of load distribution plates which lead the point loads of heavy project cargo into the ship’s structure beneath.
Outfitting
Deck Cranes (CARGOTEC-MacGregor)
Four (4) sets of electro-hydraulic single type deck cranes are arranged asymmetrical. The required 20 years lifespan of the cranes allows a SWL 40 t – 30 m resp. 60 t – 20 m for general cargo handling or SWL 24 t – 30 m for permanent grab handling. The cranes have an automatic dynamic anti-collision system and end-position switches (static anti-collision).
The new automation and security system CC 3000 allows in combination with the Electronic Load Cell System for Combined Lift (ELCCL) combined loads up to 120 tons with or without the available 12 m long T-Beam.
This ELCCL system consists of
• a load cell, which measures the load at hoisting wire
• an absolute encoder, which senses the outreach at the luffing winch
• a speed encoder, which senses the hoisting speed and direction at the hoisting winch
• double display in each crane cabin for indicating the a. m. values in single mode (own crane) or combined mode (own and partner crane)
• Drivers cabin to be increased noise-insulated and air-conditioned
• Emergency exit via cabins side window and rope ladders with aluminum steps acc. AMSA rules
Cargo Hatch Covers (Cargotec-MacGregor)
The hydraulically folded weathertight hatch covers are some of the heaviest which Cargotec has ever applied, since each of the seven bigger folding pairs weighs approx. 140 tons.
The hatch covers have a maximized breadth of 26.6 m and form a 120 m long continuous stowage plane, just interrupted by the crane columns and ventilation towers.
Two independent power packs are installed, supplied by two pumps each, serving up to 2 folding hatch cover pairs each separately and in parallel. The forces from the hatch covers when at sea are transmitted to the coaming by a number of dismountable support pads (Hardox).
The rubber seal is of sliding type, acting directly to stainless steel mating plates on top of the coaming.
Since water ingress caused by bad seal tightness would create numerous problems for the qualified transport of various goods ultrasonic tests had been carried out to identify and cure noise leakages.
For application of Uprights for Timber transport on Hatch covers rectangular stanchions with high and low pockets are welded on in 3 m distances alongside the hatch covers. Four cement feeder hatches per hold are provided with diameter 700 mm.
Propulsion
A service speed of 15 kn on design draught, defined at 90 % MCR of ME, 15 % Sea Margin was achieved by numerous tests at SVA Potsdam by testing different models, distinguished between those with cylindrical or bulbous stem, bulb-equipped or bare rudders, extended stern contours etc. At the end a bulbous stem to ensure the contracted speed was selected. Considering the large block coefficient with all its water ingress challenges we decided to install a Wake Equalization Duct (W.E.D) with Spoilers from Schneekluth.
To prove the predicted increase of propulsion efficiency we applied the Schneekluth duct at the first ship and left them out at the second one. The comparison of both the sea trials caused furious discussions, since unbelievable 10 % power savings (or 740 kW resp. 0.44 kn) had been obtained at the contract point of 15 kn, inaugurating a ship with 15.5 kn service speed finally.
At the end we updated the wind correction and finished with 7 % official gain, which means excellent 29.1 tons instead primarily assumed 31.1 tons daily Main engine consumption acc. ISO at contract speed.
Main engine
World ship’s traffic has changed significantly not in amount only but rather in average speed cargo is transported. Slow steaming has become a standard characteristic for many freighters to safe fuel costs and to employ more of the already available ships but also the steadily delivered newbuildings. Electronic main engine versions support slow steaming but also derating of engines is an appropriate tool to lower the fuel consumption.
Present designs of different types of ship’s raises the question how to combine hull’s block coefficient, available and design propulsion power and type of main engine to meet the needs in an uncertain future.
For MPC 30 a downgraded main engine of the MAN 6S50MC-C7 type was selected. Compared with the next smaller type of engine 7S46 MC-C7 at a service rating of 7920 kW we could save around 4,5g/kWh in fuel consumption. This corresponds with an annual reduction of fuel consumption of more than 200 t HFO.
For the last 4 vessels of this series it was determined to install a VTA – Turbocharger which promise to lower the fuel consumption by another 3g/kWh at part load operation.
KYMA – shaft power meter
The shaftline is equipped with a KYMA strength gauge between ME and propeller. The sensor measures the torque values, calculates the shaft power and delivers the values to a display unit in the navigation console of the bridge. Here, the navigator can observe the shaft power in real-time, depending on weather conditions but also on trim and draught variations. The trim at least can be varied by ballast transfer to find the most economical floating position. The values for actual fuel consumption are also displayed at the KYMA display.
Ballast water handling
During vessels operation it is very important that an exact recording of ballast water residuals is possible in ports where high value cargo is loaded or unloaded. Undetectable remaining ballast water quantities on board of a MPC causes endless discussions between master and loading company due to it’s commercial aspect.
Therefore the ship is provided with a Körting ballast water ejector to empty the tanks as much as possible. Sounding pipes for all ballast water tanks (opposite to most container vessels) enable check of residuals.
The ship is equipped with a Pleiger Tank Management System, which delivers all data to the workstations in ships’ office or Engine control room.
Free spaces and branch pipe connections are prepared and fitted for a later installation of ballast water treatment plant.
Special features
Ventilation tower
To carry goods like seed cake (IMO-class 4.2 – self-igniting) or Ferro- / Aluminiumsilicon (IMO-class 4.3 – emit self-igniting gases after contact with air) ventilation towers are necessary which need to have minimum distances acc. LLC between free deck and in/outlets of air. Also 50 % of ventilation redundancy is required in case of a single failure.
Preparation for dehumidifier plants for cargo holds
All cargo holds are prepared for easy installation of three Dehumidifier plants for moisture control with a drying capacity of 4,500 m³/hour each.
The aggregates can be mounted on prepared foundation in vicinity of the power pack or store rooms on main deck. Electrical connection and hose connection for wet/dry air are prepared as well.
High pressure cleaning system
The ship has a high-pressure deckwash system with a connection alongside the walkways to clean areas under high pressure.
Cargo hold cleaning after discharging
For cleaning the cargo holds after discharging and gas freeing, two sets of movable cleaning facilities are available, consisting of a water spray lance connected to the fire fighting and working air systems.
The cleaning procedure can be supported by convenient chemicals stored in 200 liter drums. After cleaning the sludge/slop residuals can be suctioned by vacuum cleaner and stored in the drum mentioned (obligatory for class B cargoes).
Gas detection facilities, temperature measurement, check of acidity
Gas detection facilities, Temperature measurement equipment and indication paper for measurement of acidity in the bilge wells of the cargo holds are provided and prepared if indicated by the cargo type.
Two sealed caps at each transversal coaming of CH 1–4 can be used for gas sampling and or cargo temperature measurement. To measure the cargo temperature a lance with sensor to be located inside the cargo before closing the hatch covers after charging. The temperature can be observed acc. the rules from outside the cargo hold.
To measure the acidity of the bilge liquid in cargo holds special sounding pipes are arranged at PS. of the cargo hold each.
Pressure test of adjacent fuel tanks
If a solid bulk cargo acc. DBC requires a tightness test of adjacent fuel tanks, the determined fuel tanks (Nos. 1-6) to be filled up to overflow alarm in their respective common overflow tanks each.
By means of this procedure the maximal hydrostatic pressure is achieved. The tightness in adjacent cargo holds has to be observed to detect leakages. After observing the DBC cargo can be loaded.
Environmental passport
The ship is classified with an Environmental Passport. This requires facilities for evacuating and exchanging Freon refrigerants and immediate gas detection, provided by Heinen & Hopman.
Resume
More than half a year of praxis shows the importance of an outstanding flexibility in a highly competitive market with steadily fluctuating risks and chances.
Hence the ship can be utilized in 3 different markets:
a) project/general cargo: currently biggest tweendecker available with state of the art tweendeck system
b) bulk cargoes: open hatch handysize bulkcarrier able to carry most types of cargoes
c) container market: comparable to a gdynia/flender 2000 teu design
Outlook
Developing optimized Multi Purpose Carriers means numerous efforts and exchange of information to get back former knowledge about this business. Even bulk carriers, designed according the Common Structure Rules require experience and optimization to attract Far East yards to contract European design offices.
Design Offices in Germany are presently facing two putatively contradictory tendencies. On one hand they are obliged to contribute with innovative ideas supporting the domestic shipbuilding and offshore industry, on the other hand they stay further close to far-east shipbuilders to prepare accurate 3D models of ordinary ships to enable their efficient production.
It can be understood that German maritime design offices are not in the position to select contracts by degree of innovation. In the meantime Neptun Stahlkonstruktions GmbH has acquired two design contracts for a Handysize bulker series of type Emerald 37 and a Kamsarmax bulker series of Type Emerald 82. Thirty five firm contracts achieved by Chinese Ouhua shipyard during 2010 speak for themselves. This design work will compensate the decreased container ship activities before more ambitious projects may occupy the future capacities.
It is about 14 years ago, when the last European-built bulk carriers and VLLC’s had been inaugurated, neglecting the recent exceptional Danish cape-size bulker deliveries. Most of the knowledge to design ships for transport of solids and liquids in bulk has gone to far-east. This may also happen with the container ship segment sooner than expected.
Resuming today after successful inauguration of the first MPC 30 – ships we can be lucky, having been able to gather experience in designing and testing optimized handling of general cargo and bulk.
