Type 065 Jiangnan-class Frigates - Design
The Navy commissioned the design and construction of new frigates in early 1962. The overall design of the Type 65 frigate was undertaken by the China Ship Research Institute 701. In order to gain time, it was decided to use existing equipment and strive to be advanced on a realistic basis. Under the auspices of the chief designer Yu Boliang, the overall design of the 65-type ship adopts the long bow hull type, which can accommodate the large-sized main engine, and has ample volume and deck area, while also providing good stability of large inclination and hull stiffness.
During the entire design process of Type 65 frigate, the designer's first consideration was the question of the main engine. In December 1962, 701st Institute in Wuhan started with the original blueprints, but apparently they were soon unable ro find the right way of replicating some intricate parts of the Soviet turbine, especially due to a lack of suitable materials. Although TB-8 and TB-9 steam turbines and several types of marine diesel engines have already begun trial production at this time, the specific development time was still uncertain and there is a danger of dragging the frigate project, so only existing mature ones can be used. Main engine, namely 37D and 43/67 diesel engines. The former is the main engine of the submarine, which cannot be reversed. The development progress of the 37DR type with increased reverse function cannot be guaranteed. The 43/67 mainframe of the 43 series (bore 430 mm in diameter) has to be used. The single machine weighs 75 tons. The overall design of the ship can bear it. However, the large dimensions, especially the great height, made other parts of the ship design to give way for this reason.
The finalized 9EDZ43 / 67 main engine has a full power of 3300 horsepower, 250 rpm, and a reserve power of 6%. Although the single power of the main engine was not high, the design of the propeller and the chimney is successful. The propeller is close to the optimized diameter and speed. A smoke guide cap is installed along the side, so that the smoke exhaust can escape upwards during sailing, which makes the ship reach 21.5 knots (design speed 20.5 knots) during actual trials. During the use of the military, it was also driven an extreme speed of 23 knots.
Designers were forced to switch to an existing powerplant akready produced in China, so the institute team was forced to redesign the hull to house it. The flush deck could not be kept anymore and a long forecastle was designed. This was not the only difference. The rest of the hull, prow and stern, witdth and lenght were identical to the Riga type, but artillery, mainly because of consideration of weight, was rearranged. Two of the 100mm turrets were relocated to the rear, only one was kept on the forward deck. Just behind, was located a 37mm AA mount. Two others were located on the wings of the new superstructure.
From February to April 1962, the designer completed three design schemes. The first scheme was three Soviet 37DP main engines and three 100 mm guns. The second scheme was two 9-cylinder 43/67 diesel engines. The three main gun scheme changed to 2 guns and anti-submarine weapons was cancelled. By June, it was decided to carry out the deepening design based on the second plan. In September 1962, the Navy approved the Tactical and Technical Task Book for Type 65 Ships, and issued construction instructions in early 1964.
The ship's hull is made of 901 manganese steel with a yield strength of 343 MPa. The length of the long stern building has a minimum height of 6.8 meters due to the main engine height of 4.5 meters, including the maintenance requirements, and the double bottom height , Exceeds the depth of the flat deck ship of this class, if the flat deck type is used, the depth of the model can only be within 6 meters, and the upper deck must leave a large opening with a width of 7 meters and a length of more than 9 meters to enable the main engine Extending above the upper deck will inevitably reduce the strength of the hull. If the type depth is changed to 6.8 meters, the hull is changed to a long deck type, and the aft weapons and superstructures must be raised by 1.3 meters accordingly, which will cause the center of gravity of the ship to rise sharply and greatly reduce the stability of the ship. The central profile depth must be above 6.8 meters, and the rear profile depth must be minimized.
Under the premise, only the ship type with a long first deck can be selected. In this way, the freeboard can also be increased, and the ship's wave resistance, large inclination stability, heaviness and strength reserve exceed the flat deck type. In September 1968, the 502 ship encountered a class 12 strong typhoon during its mission. It sailed in the typhoon for more than 40 hours. When it entered the typhoon center, the hull's maximum roll angle reached 63 degrees. The hull could be heard from the cabin. The "squeak" sound was loud, but ultimately the hull withstood the test, also showed that the design and construction were reliable.
The details of the ship type have also been carefully considered. The 7.33-degree gentle gradient transition connection between the upper deck and the aft upper deck of this type of ship can avoid stress concentration at one point, and people walking forward and backward on the upper deck. There is no need to use a straight ladder, which is more convenient.
In order to be suitable for use in the South China Sea, the Type 65 frigate has also become China's first installation of air conditioners. Due to the lack of information on the frigates of the air conditioning system, the air-conditioning designers even inspected the air-conditioning systems of movie theaters in Shanghai such as "Big Bright" and "Peace", and developed a set of rules for the air-conditioning layout and details of Chinese warships. Precedents and norms. The use of air conditioning greatly improved the living conditions of the crew. Later, when the navy used the 65 ship, it closed the doors and windows whenever it was very hot, and the air conditioning was cooled. The soldiers of other ships found this strange at first, and then were envious.
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