The 13,500 ton deadweight Combi Freighters (CF13500) have been a success series for Damen Shipyards for years. A large part of the success of this seagoing cargo vessel is its fuel-efficiency in combination with the multi-purpose cargo capabilities and a high volume-deadweight ratio. Special attention has been paid to the underwater shape, resulting in low resistance and good sea-keeping characteristics, combined with generous cargo carrying capabilities.
The main reason for the long term continuation of this success is due to the fact that Damen are continuously evolving and improving this type of vessel. This means however that the Stellar Maestro, a CF13500, is the third to last to be delivered with these characteristics. The market, according to Damen, requires an upgrade and this will become the CF14000. Therefore this article will not only describe the Stellar Maestro and some historic background of this successful series of vessels, but it will also reveal some of the upgrades we can expect in the forthcoming version.
The general concept of the Combi Freighter
The Combi Freighters are based on the proven design of previously built vessels and the ongoing improvement of vessels under construction and in design. Furthermore, customer feedback has contributed to building a solid basis for this optimisation process to evolve. The Damen cargo vessels are versatile enough to carry project cargo, bulk, grain, timber and steel coils. Dangerous cargo can be carried according to SOLAS reg. 19 II-2 excluding Class VII. Up to and including the CF13500 version, the vessels were designed to transport containers of different sizes above and below decks.
It all started years ago with a series of 12,000 ton vessels. In 2007/2008 the CF12000 was upgraded to a deadweight of 13,500 tons. This was achieved by giving the vessel a bit more length and beam. On the one hand this was partially initiated due to the changes of the rules and regulations Damen had to meet, on the other hand clients’ wishes and market demands led to this evolution. The redesign to achieve 13,500 ton primarily resulted in more stability and a relocation of the fuel tanks. This upgrade also enabled Damen to add the option of deck cranes with a larger load capacity. Furthermore, more open space was created in the engine room for all kinds of additional equipment and items to make the vessel more environmentally friendly. Damen’s design policy is based on market demands, developments up to 2012 require another evolution step to maintain this ethic.
Stellar Maestro – accommodation
As stated above only one more CF13500 will be built after the Stellar Maestro. Consequently the vessel’s main characteristics will only be described briefly, after which more attention will be paid to the development of the CF14000.
The Stellar Maestro has a high comfort level, which has been achieved by detailed noise and vibration analysis coupled with the use of high quality materials. Special attention has also been paid to the layout of the ventilation and air conditioning systems, accommodation colours, lighting and furniture. Accommodation for a crew compliment of 14 persons and four spare has been provided. The vessel includes an integrated bridge layout of ergonomic design, comprising standard consoles and displays. Eekels Elektrotechniek delivered the ship’s alarm system, bridge main console, bridge wing consoles, radio desk and was responsible for the design and installation of the electrical power generation and distribution system.
Stellar Maestro – engine room
The ship is provided with one controllable pitch propeller (CPP) which, via a shaft, is driven by an air-start, non-reversing MAK 6M43C main diesel engine of 6,000 kW. The main engine is flexibly mounted to the engine seating and flexibly coupled to the reduction gearbox with a PTO, actuating a shaft generator. The fuel system of the main engine is suitable for the use of two different types of fuel: Heavy Fuel Oil (HFO) and Marine Gas Oil (MGO). It can run on HFOs with a quality up to RMG35 (IF380) and MGO type DMA. The single spade rudder is operated by an electro-hydraulic steering gear of the rotary vane type. A CPP bow thruster, driven by a Leroy Somer e-motor, is the finishing touch to ensure good manoeuvrability.
The auxiliary equipment consists of one shaft generator, three diesel generator sets and an emergency diesel generator set. The shaft generator is driven by the PTO on the gearbox; all generator sets are make Stamford and are delivered by Caldic. Ajax Chubb Varel delivered the fire extinguishing systems for all engine spaces as well as for the holds and high fire risk spaces. ADT is responsible for the fire detection and alarm installation.
Stellar Maestro – cargo arrangement and handling
The cargo area is forward of the superstructure and is divided into two holds. The forward hold measures 26.93 x 15.80 metres and 26.93 x 10.48 metres in the bow area, while the aft hold is 69.82 x 15.80 metres. On the portside two wire luffing cargo cranes are installed of 80 tons each at an outreach of 14 metres. Both cranes can also lift in tandem by means of a hoisting traverse; they can also be synchronized by adding special software. For compensation of heeling-angles introduced by cargo handling with the deck cranes an anti-heeling system is installed. Heeling compensation is achieved automatically by pumping ballast to port or starboard side with a reversible pump at a speed of 1150m3/hr.
Stellar Maestro – deck lay-out
The Stellar Maestro has two electro-hydraulic winches with a single drum and warping head on forecastle deck for anchoring and mooring activities. On the aft deck there are two more electro-hydraulic capstans, also with a single drum and warping head for mooring purposes. At the stern we also find the required life-saving and rescue equipment, consisting of a freefall lifeboat, a rescue boat and Viking life rafts. This lay-out is completed with a deck crane for lowering and recovery of the life boat, recovery of the life rafts and other light lifting purposes.
Combi Freighter 14000 (CF14000)
In the CF14000 concept the multi-purpose character, of course, remains. This new version is still suitable for most cargoes, be it project cargo, bulk, grain, timber or steel coils. As the market for container transport has collapsed almost completely, most container features are omitted. However, whilst the vessel is still semi- container suitable, the design speed of the vessel does ideal for a container feeder.
The additional cargo capacity will primarily be found in re-arranging cargo holds and tanks, whilst maintaining the vessel’s principal particulars and hull form. This is due to the fact that ship’s lines simply could not be improved anymore. Tank capacities, in most cases, can be reduced, as a result of making better use of modern engine technologies, running the main engine at a more economical speed and thus lowering fuel consumption. The lower speed is acceptable, and in some cases even desirable, in all current shipping markets for the above mentioned cargoes. Another major issue that allows Damen to gain additional deadweight, is by improving production technical aspects and using even better quality material, thus optimising hull weight.
Yet again the shipyard has demonstrated their flexibility to adjust to changing markets: they already had a good basic design, with good stability, trim and a proven hull construction. Nevertheless the Damen staff saw an opportunity to improve and gain another 400 dwt.
CF14000 – accommodation
Whereas the CF13500, Stellar Maestro, had accommodation for a crew of 14 persons, the CF14000 provides space for 18 persons. The superstructure comprises 14 single cabins and two double berth cabins all with heating, ventilation and air-conditioning. The ‘core crew requirements’ do not change, however training and education of new crew is becoming more relevant. For this reason the original accommodation is upgraded with cabins for two to four cadets.
Recent regulation changes dictate that more crew are carried on board ships. This requires extra seamen and there is thus a shortage of them. Therefore, to encourage more people to go to sea, it is inevitable that conditions have to be improved. These improvements include increased comfort levels, improved sound and vibration levels and decor within the living spaces. Damen is meeting this challenge head on with their usual commitment. Due to developments in piracy activities for this vessel spare or emergency accommodation will be available for ‘armed forces’.
CF14000 – propulsion and electrical system
In principle the propulsion system of the vessel almost remains untouched, with the addition that Damen now offers the option to downgrade in power. With the original 6,000 kW installed the vessel now reaches a speed of 15.3 knots at 90% MCR. When downgrading to a MaK 9M32C (4,500 kW) or 8M32C (4,000 kW) the vessel can still perform at respectively 14 and 13,5 knots at 90% MCR. These options make the vessel even more attractive when considering the fuel consumption versus the service speed.
The number (two instead of three) and the capacity (438 kVA instead of 563 kVA) of the standard diesels for the electrical system will be downgraded, as reefer plugs for container cargo are no longer required. However, for ship owners who still wish these facilities, Damen provides the three higher powered diesel engines as an option.
CF14000 – cargo arrangement and handling
The focus in the CF14000 arrangement is on the possibilities to vary the configuration of the hold spaces. With two removable grain bulkheads eight vertical variations in hold separations can be made. Beside this, these bulkheads are also suitable to be used as partial tween decks on two different heights in both holds. With this flexibility, Damen feels ship owners can create all sorts of configurations within the holds. This way it is straightforward to transport a variety of different types of cargo in one voyage, be it cargo that need humidity control or potentially volatile contents. This provides more flexibility to arrange a varied cargo in such a way to optimise logistics, reduce harbour time and maintain a good trim and stability.
The crane facilities and configuration primarily will stay as they were. However, to emphasise the multi-purpose character, Damen provides a wide range of options to modify the crane configuration. The luffing cargo cranes can either be downgraded to 60 or 40 ton, or upgraded to 120 or even 150 ton, making the vessel suitable for the light (40/120 t) and middle heavy (120/400 t) cargo market. Various deck equipment in combination with the new lay-out makes the vessel even more suitable for the bulk market in areas where no bulk (un) loading facilities are available in the harbour.