2. Outline and Features
The "Koyo Maru" is a powerful ocean tugboat embodying many features of modernization to meet the needs of the times, including above all a far greater towing capacity than any conventional tugboat of the comparable class. Equipped with some of the most advanced systems including a dynamic positioning system (DPS) and a joystick control system, the vessel is tremendously improved in maneuverability and working ease, and can be effectively operated by a small crew.
Notable features of the "Koyo Maru" include:
・ A combination of two 5,000 PS powerful main engines and fixed pitch Kort nozzle propellers provides the vessel with a maximum towing power of 132.5 tons, making it the most powerful salvage tug in Japan.
・ With its twin controllable pitch propellers, a special (Schilling) rudder with a maximum turning angle of 70 degrees, a bow thruster-equipped maneuvering actuator and the joystick control system, the vessel can meet many unusual maneuvering requirements which it would encounter when on towing duty.
・ Granted NK's notations for unmanned engine room operation (MO) and installations Registration for Navigation Bridge System (BRS1A), the vessel is fully provided for effective operation by a small crew and labor saving for maneuvering.
・ The wheelhouse has functions of an integrated bridge system (IBS), augmented by the DPS, an integrated navigation system (INS), and an Electronic Chart Display indicate System (ECDlS) among other items, so that in the future only one attendant can fulfill bridge duties in any waters. These arrangements make important contributions to navigational safety and labor saving in maneuvering.
・ The work deck arranged in the aft part of the upper deck has an ample fiat space, contributing to the safety and efficiency of work as well as to effective operation by a small crew while saving labor, and also making possible stowage of heavy items and equipment for salvaging work. An all-around field of vision is ensured for the wheelhouse, in which a total of four maneuvering stands are arranged in the aft part on both sides in addition to the central one, so that the deck officer can readily maneuver the vessel while watching the performance of duties on the work deck.
・ So that any fire can be effectively coped with while at sea, the "Koyo Maru" is provided with two fire fighting guns, a foam generating liquid tank and powder fire extinguishing apparatuses for use in fighting fire besetting another vessel. Besides them, it has a function to effectively and appropriately address oil spills of small to medium scales (by emulsification), and has a dedicated tank to store oil spills recovered from the sea surface.
Principal Particulars
Classification : NK, NS* (Tug and Salvage Purposes),MNS* (MO), BRS1A
Completion : 15, June, 1998
Length (o.a.) : 86.08 m
Length (p.p.) : 77.00 m
Breadth (mld.) : 14.50 m
Depth (mld.) : 6.70 m
Draft (mld.) : 5.80 m
Gross tonnage : 2,474 GT
Trial max. speed : 18.15 knots
Service speed : 16.2 knots
Max. Bollard Pull : 132.5 metric tons
Range : abt. 15,500 nautical mile
Main engine : Daihatsu 8DLM-40A x 2 sets
: MCR: 5,000 ps x 515/180 rpm x 2
Propeller : Controllable pitch propeller with fixed kort nozzle x 2
Bow thruster : Electric. c.p.p., 650 kW x 1
Rudder : Schilling rudder x 2
Special maneuvering equippment:
Dynamic Positioning System (DPS) with Joystick control
Communication system : MF/HF, EPIRB, VHF, INMARSAT-A, -C, NAVTEX, etc.
Navigational equipment:
Integrated Navigation System (INS),
Gyro-compass,
Auto-piolot, Radar with ARPA,
Doppler sonar, Echo sounder,
GPS, DGPS, Loran-C,
Direction finder, etc.
Towing winch and wire/rope:
Winch: 45 t x 20 m/min, 200 t (fixed)
Wires: 68 mm dia. x 1,200 m x 2 sets
Hawser, 100〜135 mm dia. x 1 coil each
Fire-fighting equipment for other vessel
Fire engine x 1,
Fire gun
(sea water/foam x 1, sea water x 1)
Powder nozzle x 1
Deck crane : 10 t x 2 sets,5 t x 1 set
Mitsubishi Heavy Industries, Ltd.
Address: 5-1, Marunouchi 2-chome, Chiyoda-ku, Tokyo 100-8315
Tel: +81-3-3212-3111 Fax: +81-3-3212-9800