Ship repair tips

The "Ship Repair Regulations" and "Minutes of Ship Repair Work Meetings" issued by the Ministry of Transport of our country have clearly classified and graded ship repairs according to the causes, scope, and interval of repairs. The maintenance department of shipping companies should formulate a plan for the repair time and cost of each specific vessel based on this. The heads of various departments on board the ship should be familiar with the scope of various types of ship repairs, in order to prepare a ship repair project application form (hereinafter referred to as the ship repair form) based on the type of ship repair, in order to avoid expanding the repair scope aimlessly and causing waste of time, energy, and funds.

The ship repair order is a basic technical document submitted by the ship and machinery departments to the shipyard for ship repair projects. It is used by the machinery department and shipyard to arrange the ship repair plan, allocate repair costs, and provide the basis for the shipyard to prepare for the construction work before the ship enters the factory for repair. Therefore, the preparation of the repair list should strive to make the parts of the ship that need to be repaired clear, accurate, and technically reasonable. Only in this way can we ensure the smooth progress of repair work and meet the requirements of technical quality.

（1） Types of ship repairs

1. Plan maintenance and repair

The hull and equipment will experience natural wear and tear during operation, which will expose certain defects and result in significant or minor damage over time. To ensure continued use, carry out planned repairs. Planned maintenance and repair include aviation repair, minor repair, and overhaul (also known as medium repair and major repair).

Navigation repair: It is a general repair project and accident repair assisted by shipyards or navigation repair stations during the operation period of a ship that affects navigation. Navigation repair should be carried out during the berthing time of the voyage in the port. Shipyards or navigation repair stations should actively attach importance to navigation repair work, arrange repairs upon notification, and conduct maintenance on board if necessary, so as not to affect the transportation and production of the ship as much as possible.

Minor repair: It is a factory repair project carried out in a planned manner according to the prescribed cycle, combined with regular inspections. The purpose of minor repairs is to eliminate transitional wear and tear during operation, ensuring the operation of the vessel until the next scheduled repair period. Minor repairs are usually carried out simultaneously with dock repairs. During minor repairs, the main task is to inspect and repair the hull, rudder, shaft system, sea valves, main and auxiliary equipment, boilers, and specialized equipment for engineering ships. Generally, only adjustments, grinding, replacement of parts, cleaning and maintenance of existing equipment are carried out. Except for navigation engineering ships, painting and reconstruction are not allowed. The basic scope of minor repairs is as follows.

(1) When the hull is corroded, remove rust and paint (if there are no corroded parts and the paint is good, do not remove rust and paint casually), replace a small number of hull components, and make appropriate patching or excavation for locally damaged outer panels, decks, or other panels.

(2) Partial disassembly and assembly of the host, adjustment of clearances, and pouring of lead into the bearings. Unless there are special circumstances, the crankshaft of the main engine of a large ocean ship is not suspended, the crankshaft of the main engine of a large river ship is not allowed to leave the cabin, and the main engine of a large diesel engine is generally not disassembled.

(3) General inspection and repair of auxiliary equipment and piping systems can be carried out, and components can be replaced but not painted or displaced.

(4) Internal cleaning of the boiler, maintenance of accessories, and repair and replacement of some furnace tubes, small tie bars, and welding of cracks, but without peeling the furnace jacket or disassembling. Do not conduct water pressure tests without special needs.

(5) Engineering specialized equipment can be inspected and repaired, and vulnerable components such as dredging tools, mud pumps, pile hammers, and winches can be replaced.

The interval for minor repairs is 12-18 months for motor boats, engineering boats, refrigerated barges, food barges, first level oil barges, 18-24 months for beach boats and barges, 24-36 months for cargo barges and oil barges below the second level, and some barges do not have minor repairs. The upper and lower limits of the interval period are determined by the technical department of the shipping unit based on the navigation area, operating conditions, and equipment conditions, but cannot exceed the upper limit.

Maintenance is a factory repair project that involves 2-3 minor repairs at regular intervals, combined with regular inspections. The purpose of maintenance is to inspect the ship's hull, main and auxiliary equipment, and other devices. For major defects that cannot be resolved during minor repairs, it is necessary to maintain the strength of the ship and the operating conditions of the main equipment. Any problems discovered during maintenance should be resolved, but for related projects that can be used until the next minor repair, records should be kept and continued to be used for future minor repairs. The basic scope of maintenance engineering includes:

① Regular inspection of dismantling and installation projects as required;

② Remove rust and paint when the hull is corroded;

③ Repair and replace some of the ship's hull, deck, and skeleton;

④ The host is allowed to be disassembled for repair and the main components can be replaced; Auxiliary machines can be repaired outside the cabin or replaced as a whole;

⑤ The boiler is allowed to extract the furnace liner, replace the combustion chamber, and conduct a water pressure test according to the inspection regulations;

⑥ During maintenance, painting and renovation are generally not carried out. However, for renovation projects with significant benefits in operation but a small amount of work, after demonstration and approval by superiors, they can be combined with maintenance;

⑦ The specialized equipment of engineering ships should be dismantled and inspected, and it is allowed to replace the main components and specialized electrical equipment of dredging, pile driving, lifting and other equipment.

Maintenance is a type of planned repair that determines the repair items in accordance with the principles of diligence and thrift. Generally, the superstructure is not replaced, and the main engine and boiler are not replaced for large ships,

The interval for maintenance is 4 to 6 years for motor boats, engineering boats, stranded boats, refrigerated barges, food barges, first-class oil barges, and offshore steel barges; Steel barges on rivers take 6 to 9 years; The cargo barge and oil barge below the second level are not under maintenance.

The above repairs are mainly arranged based on intervals, and their scope of work is only a principle division. Due to the complexity of ship types and models, as well as the different technical conditions of ships, if problems are found, they should be solved truthfully according to the specific situation. For minor repairs, individual maintenance scope works are allowed.

2. Accident repair

Accident repair refers to the repair of the damaged parts of a ship caused by an accident. If the scope of the repair is not large, it can generally be carried out along with the navigation repair project. But if the scope of the project is large and aviation maintenance is difficult to handle, repair plans still need to be arranged

Draw. The project, scope, and deadline for accident repair shall be based on the actual damage situation and time limit stated in the ship inspection report of the ship inspection agency

Request to confirm. Before carrying out repairs, accident repairs still need to issue a repair order and hand it over to the shipyard responsible for the repairs. For minor

The damage caused by the accident can be recorded and maintained until the planned maintenance and repair, provided that it does not affect the airworthiness performance or hinder operation

Reason. Accident repair projects should be compiled into a centralized repair list, specifying "accident repair", and requiring shipyards to cover the repair costs for this part

Stamp with the words "accident repair" as proof of claim.

3. Basic restoration and repair

For ships that are no longer usable, repairs are required to restore their seaworthiness and hull strength, such as repairing the wreckage of sunken or fire damaged ships. This type of repair project is massive, requires huge amounts of capital, has a long repair period, and has poor economic benefits, and is now rare.

（2） Organizational management of ship repair

1. Establish a ship repair system - maintenance, management, and repair system

Adopting "preventive measures" for ships, that is, having crew members maintain them during daily operations. The better the maintenance and the more effective the preventive measures, the smaller the scope of repair work; On the other hand, if the "ship repair measures" are appropriate, the quality of ship repair will be high, the repair cycle will be short, and the longer the time it takes for the repaired ship to maintain normal technical conditions during operation, the easier it will be for the crew to carry out maintenance.

2. Pay attention to ship repair technology, shorten the repair cycle, and improve economic efficiency.

(1) Thoroughly identify and determine the scope of the repair project in advance, fill out the repair order, and provide adequate support to complete the necessary preparations for the repair project in a short period of time;

(2) Establish a normal and appropriate relationship between shipping units, ship repair units, and ship inspection units to ensure the quality of ship repair and improve the speed of ship repair

(3) Fixed point ship repair, such as Yangtze River ships being repaired in shipyards along the Yangtze River;

(4) Ship repair shall be carried out in accordance with the "Technical Standards for Ship Repair" issued by the Ministry of Transport, and the repair plan and process shall be selected based on the specific conditions of each factory.

（3） The main work of ship repair

1. Prepare to remove the ship components that need to be repaired, and dismantle the machinery, piping, furniture, equipment, etc. that hinder the work.

2. Basic work is the direct elimination of ship defects, which involves repairing or remaking disassembled parts such as components and parts, and then assembling them. After installation, a test should be conducted to check if the performance has been restored, improved, or enhanced.

3. Auxiliary work provides convenient preparation and basic work, including setting up scaffolding for the work site; Connect power and energy sources such as oxygen, acetylene, wind, electricity, water, etc; Material preparation; Lifting and transportation work during the ship repair process; Clean up the site after the repair is completed.

meaning

During the operation of ships, they are often subjected to various external forces and human factors, which can cause deformation and damage, resulting in the loss of normal technical condition of the ship. The reasons for this are roughly as follows.

1. External force action

Ships are constantly subjected to bending and torsional stresses on waves due to their frequent movements such as lifting, swaying, and turning.

2. Corrosion effect

Corrosion of metals is a natural loss that occurs constantly.

3. Human intervention

Accidents such as marine damage occur due to improper use and management of ships by humans. The above is tangible damage, which can be restored to the normal technical condition of the vessel after repair.

4. Intangible losses

Due to the advancement of science and technology, the technical condition of ships has become outdated and backward, requiring renovation, renewal, or scrapping.

Due to the above reasons, ships may experience varying degrees of loss and damage during operation, which affects their normal technical condition and gradually impacts their normal operation, posing a threat to ship safety. Therefore, it is necessary to eliminate these defects through repairs, maintain and restore their normal technical condition, and prevent further wear and damage to various components of the ship.

Extended meaning

Ship repair is different from shipbuilding. It involves cutting, assembling, welding, and other open flame operations without completely dismantling the wooden facilities, mechanical and electrical equipment on board. Some ships even enter the factory for temporary repairs without completely draining the oil and water in the oil and water tanks. After long-term use, the oil and water tanks on board are filled with toxic gases. Any slight carelessness can pose a threat to personal safety and property damage. Therefore, the following safety operating procedures should be strictly followed during the ship repair process.

1. Pay attention to lighting during disembarkation work. Bring a flashlight in unlit areas to prevent falling from the air.

2. After the oil and water tank on board is opened, it is not allowed to enter at will. The department should wait for the air inside the tank to pass the test before entering for work. Attention should be paid to ventilation conditions and labor supervision system.

3. Before conducting open flame operations on fuel tanks, cabinets (including adjacent cabinets), oil pipes, etc., the fuel tanks, cabinets, oil pipes, etc. should be cleaned first, and then combustible gas explosion testing should be carried out. Only after passing the inspection can operations be carried out.

When conducting open flame operations in the cabin, pay attention to the surrounding environment and if necessary, dismantle the surrounding equipment before proceeding with the operation. After work, the workplace and its surroundings should be organized and inspected, and any sparks should be extinguished.

5. All valves and electrical switches on board must not be opened or closed arbitrarily.

When there are other electrical facilities around the workplace (including adjacent cabins) that are not related to construction, their power supply must be cut off before work can be carried out.

When there are cables and other wooden outfitting facilities around the workplace (including adjacent cabins), there should be a dedicated person to supervise open flame operations, and a dedicated person should inspect them after the work is completed. If necessary, the above facilities should be dismantled before proceeding with the operation.

After the deck is dismantled, walking on the skeleton is not allowed.

9. Unauthorized entry into unrelated compartments is prohibited. Manhole covers and watertight hatch covers that have been opened must not be closed at will.

10. The repair of the side panel should be carried out in a top-down order.