JS Nichinan (AGS-5105) is the only ship of her type of oceanographic research ship for the Japan Maritime Self-Defense Force.
Development With the shift to passive anti-submarine warfare, the collection of marine environmental data is required for efficient execution of maritime operations, and seafloor topography / sediment, tidal currents / geomagnetism, and water temperature / salt content, etc. Marine weather was interrelated and needed to be measured precisely. For this reason, the Maritime Self-Defense Force built the JDS Akashi in the plan of 1967, and in 1969, it newly formed the Marine Operations Corps as its operation unit and started marine environment information activities. After that, in the 1950s, Futami-class oceanographic research ship and JS Suma were installed, and ocean observations were carried out with a system of four vessels. Of these, this ship was planned as a substitute for the 42AGS, which was scheduled to be removed in the latter half of the 1990s, and was approved for construction in the 1996 plan based on the medium-term defense capability development plan.
Design In terms of design, it is said to be a performance-enhancing type of JS Wakasa, and the ship type has also the same long forecastle, but the displacement is increased by 1,000 tons or more. The same is true for the apparently distinctive bow bow sheave. In order to reduce wave-making resistance and prevent interference with underwater acoustic equipment at the bottom of the ship (acoustic obstruction due to air bubbles, etc.), a U-shaped frame is used for the bow and a V-shaped frame is used for the stern. Was done. The adoption of bulbous bow was the first for an ocean observation ship. The observation side is on the starboard side, and the stern deck is used as the observation work deck in consideration of the effects of stools and waves of various equipment. An A-frame crane is installed at the stern and a break-action crane is installed at the center of the port side of the observation work deck in order to put the equipment into the sea and collect it. A telescopic crane is installed at the 2nd deck level. A rear control room is installed at the rear of the 1st deck for centralized monitoring and remote control of various equipment on the observation work deck, including break-action cranes. In addition, there is an equipment storage just below the observation work deck, which is connected by a lift. As the anti-sway device, U-shaped tube type anti-sway tanks (ART) are installed on both sides of the central part of the 1st deck. The standard fin stabilizer on an escort ship is ineffective without a certain amount of footsteps, but the ocean observation ship has many opportunities to berth and observe due to the nature of its mission, so it can be effective even at low speeds. The tank method was chosen. In addition, this ART system is said to be a type called Stabilo Ace that automatically predicts and diminishes upset. In addition, the crew of female SDF personnel is taken into consideration, and as a residential area for women, there is an officer's bedroom (for 2 people) near the officer's room on the 2nd deck and a staff's living area (for 8 people) in the central part of the 1st deck. It has been placed. Also, on this ship, as the first attempt as a self-defense ship, the design of her captain's room was ordered from a private designer, which is very excellent. The engine compartment is divided into two compartments, a machine room and a propulsion motor room, and the cockpit and emergency command post is located on the second deck. A diesel-electric system is used for the main engine to reduce underwater radiation noise. It is equipped with two Mitsubishi Heavy Industries S16U diesel generators and one Mitsubishi S8U diesel generator as generators, and a variable pitch propeller is driven by two propulsion motors. In addition, these generators also serve as power supply to the propulsion generator and the onboard services, and will be an integrated electric propulsion system. In order to reduce underwater radiation noise, the main engine and main generator are double anti-vibration support, and auxiliary equipment such as the hull is also anti-vibration support with anti-vibration rubber and anti-vibration pipe joints as with conventional ships. The vibration damping material is installed on the outer panel of the hull at the bottom of the ship. The variable-pitch propeller is also a large-diameter 5-wing high-skewed propeller, and the shaft rotation speed is also reduced. In order to suppress the shaft inclination as much as possible, the height of the propulsion motor itself was kept low and placed on the side as much as possible. In addition, it is equipped with two side thrusters on the bow (thrust of 9 tons each) and one on the stern (thrust of 12 tons) to improve low-speed motion performance in the presence of wind and tide.
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