1. The ship is overloaded
This kind of damage often occurs in rubber fenders
, especially some old rubber fenders, which often cracks at weak places in the structure. Cracks are generally in the direction of the length of the rubber fenders. D-type and V-type fenders are more common. The main reason for the cracking of the rubber fender is that the ship's impact on the fenders is too high and exceeds the load that the rubber fenders can withstand.
The reason why the impact energy of the ship is too large is due to the fact that the speed of the ship and the angle of the vessel are too large. In particular, when the angle of berthing is relatively large, the stern contacts the quay and the rubber fenders before the middle of the hull, causing the powerful impact energy to concentrate on one or more fenders, resulting in damage to the rubber fenders. As a result of the excessive impact of the ship, the manufacturer pointed out that in addition to the above-mentioned reasons, there are wharf berthing larger than the designed ship type and tonnage, and the impact of storm waves on the ship.
This situation generally occurs in fixed V-shaped and D-shaped fenders. The fenders are mainly damaged by falling angles, cracks, and surface scratches. The main cause of this damage is the excessive friction between the rubber fenders and the ship.
When the ship pull in to shore at a relatively high tangential speed, the part between rubber fender and the contacting of the hull is forced to move forward together with the ship due to excessive friction, causing the fender to be sheared and damaged. In addition, during the mooring operation, the ship sometimes needs to move back and forth, and the ship shakes left and right, or up and down, which is caused by the waves. In this case, when the coefficient of friction between the ship and the rubber fender is above 0.4 (if the cable is pulled too tight), the fender may be damaged.
3. Anchorage and poor connection
This situation has occurred in all types of rubber fenders. The rubber fenders has abnormal phenomena such as looseness, dislocation, and falling into the sea. The main reasons for this phenomenon are the poor technical condition of the anchor fenders such as bolts or chains, or the failure of maintenance. The rubber fender manufacturers
reminded everyone that anchoring bolts, iron chains, and other metal materials used in fixed fenders are extremely rusty in the marine environment and are not easily replaced, resulting in poor fixing of the rubber fenders and severely affecting the normal use of fenders. Some of the anchor bolts are designed to take into account the conditions for replacement, but they are often less than ideal in actual use. Such as V-shaped rubber fender anchor bolts, the form of embedded bolt boxes. The original design intention was to facilitate the repair and replacement of anchor bolts. However, in actual use, it could not be replaced due to corrosion of iron parts, bolt deformation, etc., thereby affecting the quality of the rubber fenders, causing the fenders to fall off and be damaged.