FALMOUTHBAY轮油舱破损修复方案

On July 18, 2023, during the loading process at Tianjin Port, the vessel 'FALMOUTHBAY' suffered damage to the left side of the bottom of the No. 2 fuel tank due to improper operation by the crane operator, resulting in a partial fuel leakage. In order to repair the damage as soon as possible and resume operations, the following repair plan is designated:

The ship's crew will use the onboard transfer pump to transfer the remaining 150 tons of No. 2 fuel in the tank to other fuel tanks or ship settling tanks until the pump can no longer transfer fuel. The specific timing will be determined based on the pump's displacement and the ship's dynamics, awaiting notification from the ship or port authorities (scheduled to start tomorrow afternoon at 12:00).
After the remaining No. 2 fuel is unable to be transferred by the pump (estimated to be around 10 tons remaining in the tank), the remaining fuel will be received and processed onshore using an oil reception facility. A corresponding oil reception certificate will be issued and delivered to the ship, estimated to take 1 day.
After the remaining oil has been received, continuous ventilation operations will be conducted in the sealed compartments. Mechanical ventilation and natural ventilation will be used. After complete ventilation, personnel wearing isolated breathing apparatus will enter the No. 2 compartment to conduct oxygen and explosion testing using measuring instruments at selected points in the compartment. This is to ensure sufficient oxygen in the compartment, eliminate explosive gases, and meet the requirements for personnel to enter enclosed compartments for work (oxygen content in the compartment not less than 19.5%, combustible gases at 0, toxic gas hydrogen sulfide below 10mg/m3, carbon monoxide below 35mg/m3). Cleaning personnel will enter the compartment to clean oil residue. Due to the high temperature in summer and the fuel tank being a confined space, cleaning the tank is more difficult. According to regulations, 1 cleaning personnel will be arranged for every 2 square meters. The operating personnel will carry explosion-proof lighting equipment below 24V. Continuous ventilation (explosion-proof fan) must be ensured during the operation. The fan will be labeled with 'Fuel Tank Ventilation, No Misappropriation'. A dedicated safety officer will observe the safety of the operating personnel continuously, and regular testing will be strengthened during the operation. If any abnormal conditions occur, the operation should be immediately stopped and personnel evacuated. The operation site will be reprocessed and after sampling and analysis, the operation can continue. This process is estimated to take 4-5 days.
After the tank cleaning operation is completed, ventilation operations will be carried out again. Oxygen and explosion testing will be conducted using measuring instruments until the data meets the requirements for hot work and welding repair operations (oxygen content in the compartment not less than 19.5%, combustible gases at 0, combustible gas concentration always below the lower explosive limit of 1%, toxic gas hydrogen sulfide below 10mg/m3, carbon monoxide below 35mg/m3).
Apply for a hot work permit from the Maritime Bureau in advance to ensure subsequent welding repair operations. Scaffoldings will be set up. First, the work surface will be cleaned, and after meeting the welding requirements, qualified personnel with appropriate work certificates will carry out welding repair operations. The groove processing, assembly sequence, positioning accuracy, and assembly clearance of the components should meet the requirements of recognized process specifications. Forced assembly should be avoided to reduce internal stress in the components. If it is necessary to correct excessive groove or assembly clearance, the correction method should be approved by the surveyor. Rust, oxide scale, oil, and debris in the groove area should be removed and kept clean and dry. The number of tack welds should be minimized, and the tack welds should have sufficient height. For general strength steel, the length should not be less than 30mm. The quality of tack welds should be the same as that of the welds. Defective tack welds should be cleaned before welding. The excess height at the intersection of the butt welds should be ground flat, or holes should be drilled (through holes) across the butt welds to ensure close contact between the components and the plate, ensuring welding quality. If there are butt welds on the belly plate of continuous fillet welds, the butt welds should be welded first, and the excess height at the fillet welds should be ground flat before performing continuous fillet welding. The specific replacement and repair range and the steel grade and thickness should follow the requirements of the classification society and ship drawings.
After the welding repair is completed and passes the visual inspection, qualified personnel with non-destructive testing qualifications will conduct ultrasonic testing. The inspection should be carried out as soon as possible after 24 hours of completion of the welding. Surface testing will be conducted according to CB T3958-2004 Ship Steel Weld Magnetic Particle Testing, and penetration testing will be carried out according to the process and quality grading. The acceptance level is Level II, which means that there should be no cracks, lack of fusion, or linear defects with a length greater than 3mm on the surface of the weld. Internal inspection of the weld will be conducted according to CB T3559-2011 Ship Steel Weld Ultrasonic Testing Process and Quality Grading. The inspection level is B level, and the acceptance level is Level II, which means that the wave height is in Zone III and the hazardous defects are assessed as Level V. The allowable indications for a single defect are T/2 with a minimum of 12mm and a maximum of 36mm, which is Level II. After meeting the requirements, contact the classification society for verification and certification.
Personnel allocation:

1 safety officer
1 welder
1 onsite driver and emergency personnel
10 cleaning personnel
2 other auxiliary personnel

Material allocation:

1 oil reception vehicle
2 oil recovery pumps
2 explosion-proof auxiliary fans
1 220V welding machine
2 boxes of welding rods
1 piece of welding repair steel plate that meets the ship's requirements
2 sets of common tools
10 portable oxygen and explosion measuring instruments
1 set of magnetic particle testing equipment
1 set of ultrasonic testing equipment
40 bags of torn cloth and cotton yarn
5 buckets
2 bags of sawdust
5 shovels
5 brooms
5 garbage bags
5 bags of laundry detergent
1 set of scaffolding
2 safety belts
10 explosion-proof flashlights
50 cases of drinking water
20 boxes of Huoxiang Zhengqi water
Other labor protection and safety auxiliary tools

Safety measures:
Configure fire-fighting equipment on-site, including portable fire extinguishers, buckets filled with clean water, and sand.
Provide heatstroke prevention and cooling items on-site, including drinking water and Huoxiang Zhengqi water.
Provide emergency medical supplies such as adhesive bandages on-site.
Arrange emergency personnel and vehicles on-site.
Assign an on-site safety officer to closely monitor the situation of the operating personnel and eliminate safety hazards.