Failure of electromechanical equipment (main propulsion device, main power supply, emergency power supply, boiler, steering device) during the process of entering and leaving the harbour in ports and waterways with busy water traffic forms a great safety threat to the ships navigating in the waterway and is very likely to cause dangerous accidents. This case describes a case of fuel vaporisation caused by improper heating operation of main engine fuel system found in recent inspection, which led to failure of main engine start-up, exposing the crew's unskilled operation of the main engine fuel system, hoping to cause alertness and attention of the shipping company and the crew, to reflect on this case, to strengthen the self-inspection and self-correction, and to eliminate the safety hazards that led to the failure of the ship's electromechanical equipments.
The ship was berthed at Shanghai port on 18 April 2024, the main engine was using low-sulphur heavy fuel oil when berthed, and was ready to leave the port at 1000 hours on 20 April 2024, the main engine was not switched to fuel oil after berthed, and there was no abnormality in the main engine during the preparation period. 1117 pilot boarded the ship, and the ship left the port with the assistance of tugboat, 1140 the ship was moving in the waterway, and found that the main engine couldn't be started normally, in order to avoid the risk of accident, the ship cast emergency anchor on the spot, and the vessel was in a very dangerous condition. In order to avoid dangerous situation, the ship anchored urgently on the spot, 1145 reported the main engine failure to VTS and informed the neighbouring ships through VHF. After the emergency anchoring, the chief engineer then checked the ship's main engine system, and when checking the fuel supply system of the main engine, he found that there was a lot of foam at the vent of the fuel supply system, and the chief engineer concluded that there was a problem with the quality of heavy fuel oil. 1242 The chief engineer switched the fuel oil of the main engine from heavy fuel oil to light fuel oil, and the main engine started up and operated normally, and then sailed to the anchorage and anchored with the assistance of tugboats, and the ship provided VTS with the explanation of the failure, and characterised the reason for the failure to start up as the fuel oil. The ship provided VTS with an explanation of the failure, characterising the cause of the main engine start-up failure as a fuel oil quality problem.
According to the "Notice of the Maritime Safety Administration of the Ministry of Transport on Special Action to Prevent Failure of Ship's Mechanical and Electrical Equipment", a special inspection was carried out on the vessel to prevent failure of ship's mechanical and electrical equipment on April 21, PSCO carefully reviewed the explanation of the failure of ship's main engine submitted by the ship's side as well as the relevant information and pictures before boarding, and found that the ship had not switched the fuel oil before and after berthing, and the main engine of the last voyage between Hamburg and Shanghai was using the same heavy duty fuel, PSCO preliminarily concluded that the fuel oil had not changed. PSCO's preliminary judgement was that it was unlikely that the main engine had failed to start due to fuel quality problems.
After boarding the ship and listening to the ship's statement, PSCO launched a detailed investigation into the main engine fuel supply system, fuel filling and use, cabin alarm records, and main and auxiliary engine operating condition records. According to the ship's bunkering documents and oil record book, the low-sulphur heavy fuel oil used by the main engine was refilled in the port of Hamburg, Germany, on 30 January 2024, with a total of 1,300 tonnes, and the fuel oil started to be used on the last voyage after sailing out of the port of Hamburg, and more than 700 tonnes had been used on the ship with 600 tonnes remaining on board when it berths at the port of Shanghai, and no abnormalities were found in the main engine since it used this heavy fuel oil. No maintenance was carried out on the fuel supply system and all systems of the main engine before and after berthing, and the heating cycle of the main engine fuel was maintained continuously, i.e. the main engine and the fuel supply system did not undergo any change before and after berthing. PSCO initially decided that the claim that the main engine failed to start due to the quality of the fuel as mentioned in the vessel's fault description was not valid.
In order to further identify the cause, PSCO carried out a detailed inspection of the main engine fuel system and checked the cabin alarm records before and after the failure, and found that there were no alarms for the main engine fuel viscosity control and temperature control in the days before and after the failure, and that there was a short-lived alarm of low fuel pressure in the main engine fuel system after the main engine failed to start up on the day of the failure, at 1148. During the port call, the oil separator had been circulating and separating the oil, and no large amount of residual water was found in the heavy oil daily use cabinet and the residual discharge port of the sedimentation cabinet, which ruled out the possibility of the main engine's fuel oil system mixing a large amount of water, and the possibility of the reduction of fuel oil pressure caused by the vaporisation of water in the process of the heating of the heavy oil. Before and after the port call, the ship did not carry out maintenance on the main engine, and it was normal for the ship to switch to light oil main engine after the failure of heavy oil main engine start-up, which indicated that the ship's main engine system itself did not have any problem.
According to the ship's main engine failure statement, there was a large amount of foam in the fuel oil pipeline system, and PSCO initially determined that the cause of the failure was most likely in the fuel oil heating process, where the high fuel oil heating caused the fuel oil to vaporise, generating a large amount of foam and leading to insufficient fuel oil pressure. Afterwards, PSCO inspected the fuel supply system and viscosity control unit of the vessel, and found that the fuel viscosity regulator of the main engine of the vessel could be set in two modes: viscosity regulation and temperature regulation, and that the vessel had been using the viscosity control mode, and that the working principle of the viscosity control mode was to automatically adjust the opening of the steam heating valve according to the set viscosity value, so as to keep the viscosity of the fuel within the range of the set value, and asked the engine manager if the viscosity regulation system was normal. PSCO asked the chief engineer whether the viscosity adjustment system was normal, and the chief engineer stated that the viscosity control adjustment system was normal.
Based on the inspection, PSCO believed that the root cause of the main engine failure could be ruled out to be the quality of the heavy oil, and the engine manager approved PSCO's inspection result.
PSCO continued to track the root cause of the main engine failure, after the inspection, the ship immediately arranged the main engine manufacturer's engineers to test the main engine and the fuel supply system, through two days of testing found that the root cause of the main engine start-up failure is the failure of the fuel viscosity control system sensor failure led to the failure of the fuel viscosity control system, the fuel oil vapour heating valve opening is not matching the command, the heating valve opening is too large, the heating is too high, leading to the failure of the fuel oil viscosity control system, the fuel oil vapour heating valve opening is too large, the heating is too high. Under normal circumstances, the fuel viscosity alarm should be triggered, but due to the failure of the fuel viscosity control system sensor, the fuel viscosity has been displayed as normal, and there is no record of the fuel viscosity alarm in the fuel system alarm of the main engine, which ultimately determines that the root cause of the main engine's failure is the failure of the fuel viscosity control system sensor, which leads to excessive heating of the fuel, resulting in a large amount of foam in the fuel supply system and triggering the main engine to start up. It was finally determined that the root cause of the main engine failure was the failure of the fuel viscosity control system sensor, which led to excessive heating of the fuel, causing the fuel supply system to generate a large amount of foam and triggering the main engine to fail to start, which also verified PSCO's initial judgement of the root cause of the failure.
After the root cause of the fault was identified, the RO issued an additional inspection report. Considering that the vessel had already switched the fuel viscosity control system to temperature control mode and had arranged for the engineers to strengthen regular inspections, and that the vessel was about to go to a nearby shipyard for repairs, and that the vessel guaranteed that the fuel viscosity control system would be replaced at the shipyard, PSCO conducted a review of the defect, and then continued the voyage to the nearby shipyard to carry out the repairs and replace the new fuel viscosity controller at the shipyard. Replacing the fuel viscosity control system with a new one.
Firstly, strengthen the emergency response. When the ship suffered from the failure of electromechanical equipment, according to the navigational condition and the lack of ability to maintain direction and speed after the ship lost control, the ship should immediately take effective emergency safety measures, manoeuvre the ship by using the residual speed of the ship, control the ship's position by using the double anchors, and report the ship's loss of control to the neighbouring ships in a timely manner through VHF and other means of communication to remind the neighbouring ships to take evasive measures to avoid the occurrence of secondary accidents.
Secondly, find and eliminate the root cause of the failure. Neglect of the root cause of the failure is not conducive to the subsequent improvement of the safety management level of the management company, nor is it conducive to the analysis of the cause of the vessel's failure and the subsequent judgement of the level of safe navigation of the vessel. The captain should truthfully report the failure phenomenon and preliminary cause analysis to the management company and the maritime management department to find the root cause of the failure, so as to facilitate the subsequent targeted implementation of corrective measures, for the cause of the failure of the ship can not be identified, should be timely invited to equipment manufacturers, shipyards, and other professional organisations such as engineers boarding the ship for testing to find out the cause of the failure to be promptly eliminated to eliminate the hidden safety hazards completely.
Third, improve the shore-based support. Shore-based support is the fundamental guarantee of ship maintenance, for the ship has found the ship equipment failure and key equipment spare parts application, shipping companies should do shore-based support, timely supply of ships, such as can not be timely supply of ships should be done in a timely manner to provide technical guidance and reminders, the development of a temporary operating procedures, to eliminate the equipment failure caused by the ship's voyage safety hazards.
Failure of ship's mechanical and electrical equipment is a great safety threat to the ship itself and other ships in the waterway. Shipping companies and crews should strengthen self-examination and self-correction, improve safety awareness, enhance the level of safety of the ship, and avoid secondary accidents caused by failure of ship's mechanical and electrical equipment. In this case, the ship's emergency response was timely, and although it did not lead to other secondary accidents such as collision, the ship's schedule was delayed, and the lesson learnt was quite profound.
https://www.cnss.com.cn/html/shipbuilding/20240724/354171.html
|
Back:
Next:
