Deepwater drilling driving progress of azimuthing thrusters

Aquamaster UUS 7001 units being loaded at Rauma harbor in December, destined for installation on the Discoverer Enterprise at the Astano ship yard in Spain. [23,980 bytes]
Part of the total consignment consisting of six operating and one spare units built by Kamewa for the Discoverer Enterprise. [32,057 bytes]

Kamewa Finland, part of the Kamewa Group and formerly Aquamaster-Rauma, responded to a buoyant offshore sector last year by opening a new Kamewa office in Singapore to oversee its growing business in the Far East and a new joint venture assembly shop in Gdansk for winches.

Kamewa is experiencing its greatest growth in the provision of Aquamaster thrusters for dynamically positioned drilling rigs operating in deepwater areas and has secured a number of orders for equipment that will operate in ultra-deepwater.

According to offshore manager, Jarmo Savikurki, these orders are a testament to the years of design, testing and development that have gone into the company's Aquamaster azimuth thrusters. "Reliability and efficiency are critical, particularly when you are faced with the technical and economic challenges of deepwater exploration," says Savikurki.

Orders received last year include units for the Transocean Offshore Discoverer Enterprise, which were completed and delivered to the Spanish Astano yard last December. The contract called for propulsion and thrust for dynamic positioning. Kamewa supplied by six Aquamaster UUS 7001 units providing a total output of 30 MW. The Discoverer Enterprise has a multi-year contract with Amoco and should commence drilling in the Gulf of Mexico in the summer.

An order also received last year, for a newbuild drillship commissioned by Conoco/ Reading and Bates, has been followed up by two more identical orders. "The design of all the vessels is the same," says Savikurki, "so we are supplying identical equipment for all three." Each vessel will be equipped with six underwater demountable Aquamaster UUS 6001 azimuthing thrusters providing a total of 33 MW and fitted with Kamewa's patented tilted nozzles.

The drillships, 220 meters long and 43 meters wide, are being built by Samsung Heavy Industries in Korea and will be capable of drilling at water depths up to 3,000 meters. "The hydraulic steering gear has already been delivered for the first ship," says Savikurki, "and the thrusters will be delivered to Korea by April." Shipment of equipment for the other two boats will follow on at six month intervals with the final consignment due in early 1999.

Late last year, Kamewa received an order from Falcon Drilling to supply UUC 7001 Aquamaster thrusters for two bulk carrier cargo vessels that are being converted into dynamically positioned drill ships at the Lisnave yard in Portugal. Each vessel will be supplied with seven 5.5 MW thrusters, six of which will be installed, with one kept as a backup. The UUC designation denotes that the thrusters are demountable and can be installed underwater without divers.

This method of installation has been developed so that the thrusters can be guided into place by ROVs with connections taking place inside the vessel. Each thruster weighs around 75 tons and will be delivered by the autumn of 1998.

Another order under way is for four UUC 6001 azimuthing thrusters to be fitted on a drillship being built at AESA Porto Real for Statoil. The vessel will have conventional propulsion in addition to azimuth thrusters, together with two Kamewa tunnel thrusters. The 4.5 MW thrusters are due to be delivered this autumn.

Supply vessels

In addition to supplying equipment for drilling facilities, Kamewa is a major supplier of propulsion systems for offshore supply vessels. Several thruster systems are currently on order for supply boats including equipment for a multipurpose field supply vessel/pipe carrier for the Norwegian company Olympic Shipping.

Olympic is building a similar design to the Skandi Marstein, a flagship supply boat owned by District Offshore which has been in operation for two years and is fitted with Kamewa thrusters. Like the Skandi Marstein, the Olympic Shipping vessel will be fitted with twin Contaz azimuth thrusters, a recently developed concept based on a new type of contra-rotating azimuth thruster. Combined with a retractable Aquamaster UL 1201 and a Kamewa 2200 tunnel thruster, the package provides a high level of manueverability.

Deepwater drilling has also affected the design of supply boats which need larger cargo capacities as supply trips to remote drilling locations need to be less frequent. One such example which is being supplied with Kamewa equipment is the Ensco Pilot, the first of a series of stretched supply boats being converted or upgraded by Ensco Marine in Houston. Here, a conventional 180-ft OSV hull design was separated at near midship and fitted with a 40-ft mid-body to accommodate additional liquid mud, dry bulk and deckspace. The vessel has also been equipped with dynamic positioning for which Kamewa has supplied Aquamaster US 1401 azimuth thrusters and tunnel thrusters.

Winches

Since the autumn of 1997, the company expanded its facilities by opening an assembly shop for winches in Gdansk, where Kamewa operates in a joint venture with Remontowa. Increased offshore activity, particularly in the deepwater regions, has seen an increasing demand for its anchor handling/towing winches. This has also led to a concentration of its activities in these products.

Last year Kamewa won a contract to supply winches for four new generation anchor-handling supply vessels being built for A P Moeller at the Keppel yards in Singapore. Each vessel will be fitted with a complete package of Rauma winches including powerful anchor handling/towing winches, anchor windlasses, mooring capstans, tugger winches and wire storage wheels. Shipment of the first package to Singapore is due in April with deliveries taking place at three month intervals thereafter.

According to the Manager for Offshore Products, Ilkka Myrsky, Rauma winches offer considerable advantages. "The electrically driven winches provide greater control flexibility and save both space and weight," says Myrsky.

The electrical system is based on an AC electric pole-changing motor drive where the electric motors are fed directly from the electrical network of the vessel without any additional power converters or governors. This ensures a good overall efficiency of the mooring system and a minimum number of components. DC drives and frequency controlled AC drives are also included in Rauma electrically driven winch systems.

In addition to the four vessels being built in Singapore, A P Moeller has also ordered two special offshore winches for an anchor handling tug/supply vessel being built at Simek in Norway.