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The relation of rubber fender and mooring stability
Oct 25, 2018

The construction and operation of qinhuangdao coal terminal of the world energy port; the quality of rubber fender always restricts the use of production berths; the safety of piloting and mooring of ships and the scheduling of production ships is troubled.The cause of rubber fender failure is not accident and operation management, but has deep theoretical root. To solve this problem, it should first analyze and study the best countermeasures in fender design, selection and material manufacture.The port authority has held several special meetings on this issue. The author intends to make in-depth discussions on the connotation and extension of the design, manufacture and use of rubber fender, so as to provide reference for new construction projects and further improve the decision-making awareness of fender quality and model selection in qinhai port.

In order to reduce the collision force of ships when they are away from the berth, and prevent the damage accident of ships and docks caused by direct collision with the berth, anti-shock equipment should be installed at the front of the wharf.Chinese ports began to gradually adopt rubber fenders around 1970.At present, the rubber fender used in various countries in the world can be divided into five categories: compression type, inflation type, shear type, rotary type and hydraulic type, of which the first two types are most widely used.Most of the rubber fenders used in Chinese ports are domestic compression fenders, including cylinder, D, V, drum, floating and foam rubber fenders.

There are 3,771 rubber fenders, including 24 drums, 59 inflatable hats, 2,948 D seals, 460 V seals, 274 barrels and floating seals.The selection of fender structure depends on ship type, dock type and tide, wind and wave conditions.Rubber fender has the advantages of big energy absorption, small reaction force, wear-resisting, insect-resistant, simple installation and convenient maintenance. The fender of all countries in the world has reached the degree of rubberization, and the total fender investment of China's ports can reach 40 million yuan every year.

The spacing and elevation of the rubber fender arrangement is very important to ensure that the ship can not directly touch the dock bank wall at the most unfavorable berthing Angle permitted by the regulations, and that the ship can safely berthing at different tide levels and different draught, which has a strong adaptability to the ship berthing at different tonnage.When selecting and determining the fender arrangement scheme of the first, second and third stages of coal wharf, the berth stability conditions of different types of tonnage ships must be met.The fender is a stable energy absorbing equipment for the ship at the berth. The size of the reaction force determines the motion of the ship in three-dimensional space.Both can generate a large amount of ship collision energy by the ship pier, which requires the newly adopted fender to have good energy absorption characteristics.The allowable wave high cumulative frequency in front of the wharf is generally 4%.Abroad has adopted effective wave height of 3%.Since the factors affecting the allowable wave height in front of the wharf are complex, the impact energy of the ship at the wharf and the ship motion parameters caused by the wave along the river, the wave on the river and the wave on the river must be calculated.

When the allowable wave height and wind force in front of the coal wharf of phase I, ii and iii engineering are in accordance with transverse wave H4=1.0m and consequent wave 1.5m, and the wind force is no more than 6 grade 10.8 ~ 13.8m /s, the collision force generated by the hull against the wharf is to protect the structure of the wharf and the safety of the ship body through fender.According to the rolling period of ships of different tonnage, it is necessary to avoid the possibility of the ship hitting the pier and wave resonance, and to allow the wave height to be low.The deformation of rubber fender and its corresponding reaction energy absorption.It reflects the allowable wave height, wind force and water flow condition in front of the wharf.The ship's bearing pressure is related to its Angle of pressure, and the current is close to the berth. At this time, the transverse flow has little impact and the fender reaction is also small. However, the adverse effect of waves on the operation of the ship still exists.30,000-50,000 DWT in the wave H= 1.0-1.5m.The period is from 6 to 8 seconds, and the ship's heave is o.About 5m, swinging across o.At the moment, the rubber fender should be able to withstand a certain shear force. However, there are frequent maritime accidents where the inflatable fender root of qinhai port breaks.To this end, this paper is discussed according to the following procedures: represents the ship type and depends on the speed of the determination;Calculation of effective landing energy on behalf of ship type;The type, arrangement and accessory equipment of the anti - punching equipment are determined by calculating the counterforce of the anti - punching equipment.

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