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Credo: Easy-access bulk carrier
for short sea trading

Credo – the product tanker that became a bulk carrier when turned into a firm order. Photo: Pär-Henrik Sjöström

 

The geared bulk carrier Credo of the Swedish shipping company Rederi AB Donsötank was originally intended to be a product tanker. When turning the option into a firm order, the tanker became a bulk carrier due to a new co-operation with ESL Shipping in Finland.

Rederi AB Donsötank is one of the successful Swedish family-owned shipping enterprises on the small island of Donsö off Göteborg. Donsötank has a long tradition of shipping, starting at the beginning of the 19th century. The company was registered in 1953 and today the fleet includes two bulk carriers and four tankers. In addition, there is a product carrier on order for delivery in September 2007.

In addition to its tanker operations, where Broström Tankers acts as commercial operator, Donsötank has been involved in shipments of raw materials for the Finnish steel industry since the late 1970’s. In 1991 the Finnish steel manufacturer Ruukki took the bulk carrier Madzy on time charter. When the Finnish shipping company ESL Shipping Oy in 2004 won the contract for Ruukki’s shipments of raw materials, ESL Shipping continued to operate the Madzy on TC.

	The comfortable bridge on Credo is designed for a one-man watch. Photo: Pär-Henrik Sjöström

Own design
Before the re-organisation of Ruukki’s shipments of raw materials, there had been discussions about ordering a newbuilding for this traffic. Together with the consulting naval architects and marine engineers FKAB, Donsötank developed a design for a 13,000 DWT geared bulk carrier, tailor-made for Ruukki’s shipments. The design was based upon the experience of operations with the Madzy and the previous bulk carrier carrying the name Credo.

When first contacting ESL Shipping, Donsötank had an option with Shanghai Edward Shipyard for a sister vessel to the newbuilding H132, the product carrier Evinco. As ESL Shipping had no luck searching for newbuilding slots at the shipyards for a fast delivery of a sister vessel to their Eira, it was instead decided to transform Donsötank’s option into a bulk carrier to be operated by ESL Shipping. The contract was signed in late 2003 for the delivery of a 20,000 DWT bulk carrier to a company jointly owned by Rederi AB Donsötank’s subsidiary Donsöshipping KB (65 per cent) and ESL Shipping Oy (35 per cent).

Donsötank’s earlier 13,000 DWT bulk carrier project was therefore re-activated and enlarged. To ensure fast and uncomplicated building of the vessel, the design was to be kept as close to the design of Evinco as possible.

The shape of Credo’s hull is almost similar to Evinco’s, but the bulk carrier is 3.8 metres longer and has a 0.9 metres larger beam. The deadweight of Credo increased to 21,353 tons compared to the 19,999 tons of Evinco. The layout of the superstructure is similar on both vessels with the exception of minor details. The bulk of the equipment installed onboard is also identical on both vessels. However, the machinery of Credo is conventional, while Evinco is equipped with diesel-electric machinery and podded propulsion.

	The main engine on Credo is a Sulzer 6RT-Flex50. Photo: Pär-Henrik Sjöström

Winter traffic
Designed for all types of general cargo including containers, the Credo is optimized for bulk cargo. She is operated by ESL Shipping on a long-term charter and employed with shipments of dry bulk cargoes such as coal and iron ore pellets in the Baltic Sea and North Sea. The vessel is built to highest Finnish/Swedish Ice Class IA Super, to enable smooth year-round traffic also to the ports in the northern part of the Gulf of Bothnia and the easternmost part of the Gulf of Finland.

The forecastle deck is enclosed to protect the mooring winches and hatch number one from freezing spray. However Donsötank chose to go for a solution with a bulbous bow instead of an icebreaking bow. The advantages of a bulbous bow in open water were considered to be more significant for the overall performance of the vessel than the possible disadvantages in ice. The bulb is specially designed for navigation in ice and equipped with an ice knife, which is shaped to fit in the towing notch of an icebreaker. Simultaneously it prevents the bulb from coming too close to the towing icebreaker’s propellers.

Easy to operate
One of the main features at all stages of the project has been to make the vessel as easy to operate as possible. For example, after thorough evaluation the owner decided to build Credo with two holds instead of three.

“This saves time, as it is faster to clean two holds than three. The need for lifting front loaders up and down in the final discharging stage is also reduced, and there is more space for them to operate in the holds”, explains Credo’s Master Stefan Lorensson, who is also a member of one of the owner families and has actively participated in all stages of the project.

The hatch covers are in open position stowed fore of hold one and aft of hold two respectively. As there are no hatches stowed in the midsection between the holds, this arrangement provides excellent access to the holds, both when using the ship’s own cranes and cranes ashore. It is possible to discharge a full cargo of 20,000 tons in 15 hours with the ship’s own cranes.

“Because the ship has become popular among the stevedoring workers in the ports we frequently visit, we have realised that this was the right decision,” says captain Lorensson.

Three cranes
The vessel is equipped with three cargo cranes supplied by MacGregor Hägglunds. The lifting capacity is 37.5 tons, using hook, and 30 tons using 12.5-cbm grabs on 28 metres’ outreach. The grabs installed are owned by ESL Shipping and they are of the same type as on their own vessels to ensure the possibility to change them for service among the vessels. When using cranes ashore the vessels’ own cranes may still be kept in stowed position, as the grabs are stowed in cradles, which are not attached to the cargo hatch.

The total volume in the cargo holds is 25,667 cbm. With the exception of the foremost part of hold one, the holds are box-shaped. If in the future the need arises to carry containers, the dimensions of the holds are adapted to standard containers. The hatches are strengthened for loading containers on deck, but in the present traffic this possibility is not fully utilised. For the time being there are lashing points for two bays of containers on the aft part of hatch two, providing a total capacity of 16 TEU.

Low-speed engine
Propulsion is provided by a direct-coupled Wärtsilä/Sulzer 6RT-flex50 low-speed diesel engine, which is manufactured on license by Diesel United in Japan. The output of the engine is 9,720 kW at 124 rpm.

According to Wärtsilä Corporation, the Sulzer RT-flex engines are the first low-speed diesel engines to have electronically-controlled common rail systems for fuel injection and valve actuation. This delivers benefits such as smokeless operation at all operating speeds, lower fuel consumption, reduced maintenance costs and lower steady operating speeds for better manoeuvring.

When operated in fixed speed mode with the shaft generator coupled, the speed of the engine is 116 rpm. The engine may also be operated in variable speed mode within a range from 88 to 124 rpm. Service speed is 14 knots fully loaded but the max speed in loaded condition on 80 per cent MCR is about 16 knots.

When using the shipboard cranes the need for electrical power is large and therefore three auxiliary engines of the type Wärtsilä 4L20 developing 750 kW each have been installed. They are coupled to AVK-alternators. In addition to that there is a shaft generator, supplying the ship with electrical power at sea.

Excellent manoeuvrability is provided by a Becker-rudder and Brunvoll-thrusters in the bow (850 kW) and the stern (670 kW). The bow thruster is of a retractable type and can be turned 360 degrees when lowered. It can also be used as a take-me-home propulsion unit, if the main engine should fail.

One-man bridge
The superstructure is almost identical to that of the Evinco. The main difference is that there is a cargo office on poop deck on the Credo, as this is more convenient for the deck officers, who have to be on deck supervising loading and discharging.

The bridge is designed for a one-man watch and is classed by DNV with the notation Naut-AW. The layout of the bridge has been developed by the owner in co-operation with FKAB and SAM Electronics, which is the supplier of the integrated navigation system Nacos.

The main object when planning the bridge was to create an ergonomic working environment for the officer on watch, including free view of virtually the whole horizon.

Therefore the cockpit is situated on the starboard side of the centreline to minimize the negative impact from the massive deck cranes. To obtain free view aft the funnel is asymmetrically situated on the port side of the vessel.

On both wings there are manoeuvring posts for berthing. If the vessel is using its own cranes it berths port side alongside, if not, then berthing with starboard side to the quay.

Futuristic funnel
The design of the funnel is out of the ordinary, including two wings, leading the exhaust gas pipes horizontally to both sides. The first vessel in the fleet to obtain this feature was the Evinco. Although it gives a futuristic impression, the design is quite functional. On the earlier vessels the parabolic antennas were situated on the roof of the bridge, but on certain headings the radar mast caused a blind sector with bad reception. By situating the antennas on the wings of the funnel there are fewer obstacles near them.

There is one antenna on each funnel wing, one Seatel for reception of television signals and one for V-Sat satellite communication. The V-Sat system is being installed, and after completion it will enable broadband connection online via the ship-based wireless local area network. This also enables ship-to-shore phone calls at the same cost as Swedish local calls.

Satellite phone
Until the V-Sat system is operational, the Internet is accessed via satellite phone. The crew members have e-mail addresses of their own to keep in touch with the world outside. “This is mostly appreciated and almost a condition for getting young people to sea, as they take it for granted that these connections are available”, says captain Lorensson.

The minimum manning level of the Credo is set to 12 persons, but including an extra deckhand and two trainees there was at the time of writing 15 persons on board. According to the Swedish TAP-agreement, six of the basic crew are from Sweden and six from the Philippines. The accommodation includes a total of 20 cabins with 23 beds.

The standard of the accommodation area is proportionately high with some interesting details in the interiors, featuring wood and other traditional materials. Although Credo is a cargo vessel, much effort has been put to the comfort of the crew. Also the finish of the work leaves nothing to be desired.

“The additional cost for creating a nice environment for the crew is minimal, especially when building a vessel in China”, explains captain Lorensson.

There is plenty of space in the large superstructure, including a common mess for the whole crew, two dayrooms and a well-equipped sports room with a sauna.

//Pär-Henrik Sjöström

Credo
Geared bulk carrier built by Shanghai Edward Shipbuilding Co. Ltd, China, for Credo AB (joint venture owned by Donsöshipping KB 65 per cent and ESL Shipping Oy 35 per cent), Donsö, Sweden. Newbuilding No H134 Delivered on March 20, 2006 Classification: DNV, IMO No: 9319064
L.o.a.	159.26 m
L.p.p.	151.9 m
Beam	24.60 m
Draught	9.40 m
Depth (upper deck)	13.5 m
GT	16,690
NT	6,548
DWT	21,353
Cargo hold volume	25,667 cbm
Cabins/beds	20/23
Crew, minimum	12
Tank capacities (cbm):
Ballast water	9,127
HFO	786
MDO	127
Fresh water	90
Machinery:	1 Sulzer 6RT-flex50 (9,720 kW at 124 rpm)
Service speed:	14 knots

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Latest update 21-12-2006 14:41