Analysis Shock Phenomenon on Static Diving Test of Diesel Electric Submarine

Abstract

In the series of disel electric submarine construction, the crucial activity is post-ship launching test. Harbor Acceptance Test (HAT) is a function test of equipment, systems, and integration between systems. While Sea Acceptance Test (SAT) is a test to record and file the posture, character, and operational capabilities of submarine. In the SAT series, static diving (SD) tests are scheduled at an early stage. The purpose of the SD test is to determine the posture of the riel submarine versus the design, i.e. stability. Another thing in the data from this test is the ship's tightness, data riel load (DWT), the penetration of equipment that penetrates pressure hull such as stern tube, hydroplanes, hoistable mast, torpedo tube, compressed air bottles, hydraulic line, electrical insulation resistance, as well as sensors equipment (communication, sonar, UWT, echosounder, navigation, speedlog, sonar and radar). The goal is to ensure the safety of the ship and crew in the next SAT stage. In static diving tests, there is always a shock phenomenon where the submarine loses buoyancy and falls with the angle of trim to aft. Efforts by blow out the compensating tank (CT) for recover the submarine is not effective even late until the submarine sat on the seabed. This has an impact on the suction line by mud sediments to the seawater cooling system, also potentially damaging ship equipment: sensors, hydroplane and propeller. The shock is caused by the apparent buoyancy of the equipment in the bridge (sail) area that exposed to the atmosphere, where when entering the final stage of ST, the apparent buoyancy changes instantly to weight force. So there is a submarine imbalance, namely weight exceeds buoyancy and LCB exceeds LCG. This thesis uses quantitative research with Fault Tree Analysis (FTA) method to identify the source of the shock, the weight value of the shock, the initial angle of the shock (trim to stern), terminal velocity, either efforts and solutions to eliminate the imballance  in order to achieve the efficiency and effectiveness of the static diving process, as well as safety to continue the series of submarine SAT tests.