Qingdao Luhang Marine Airbag and Fender Co.,Ltd

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Water-Injected Pneuamtic Rubber Fender
- Oct 23, 2018 -

Water-Injected Pneuamtic Rubber Fender

1. Introduction

Water-Injected Pneumatic Rubber Fender is a special fender developed from mere pneumatic fender. The fender is injected with certain volume of water to allow it to sink into water for certain depth. This function is to make up the shortage of mere pneumatic fender which is always floating on the water. The fender is used on conditions that the distance between dock level and water level is shorter than the fender’s height or for submarines or for the vessels of which the distance between the board and water is shorter than the fender’s height. The fenders can be equipped with Tire Chain Net or just the fender body.


                         2m x 3.5m                                                                     2m x 3m

2. Structure

2.1 External Structure: 

It is same as normal pneumatic fender which has a cylindrical shape body and two hemispherical ends. Outside is equipped with Tire Chain Net or just the fender body it self. On both ends, there is one flange with an air valve and a water valve. Below is a drawing of 2m x 3.5m for reference:


2.2 Rubber Structure: Please refer to drawing above.

The rubber material for this fender has 3 main layers: Exterior layer of mere rubber, Middle layers of cord-reinforced rubber and interior layer of mere rubber. The rubber material at different positions is made with different formula to make it have special performance. The exterior layer is friction-resistant, puncture-resistant and aging-resistant for protection of the fender. The middle layers are reinforced by strong nylon cords to let it have a strength of busting-resistant. The inner layer is for air or water leaking- resistant.

2.3 Thickness of the rubber:

Pneumatic fender of 50KPa has a different number of cord-reinforced layers according to different body diameter. For fender in size of 2m x 3.5m or 2m x 3m, it has 6 layers of cord-reinforced rubber. Total thickness of the fender wall is about 8.2mm. Below is a picture of the rubber wall cut section:


3. Performance of Water-Injected Pneumatic Fender

Water injection does not affect the fender’s performance of Force Reaction and Energy Absorption. Below is the performance of fender in size of 2m x 3.5m and 2m x 3m:


4. Usage of the fender

4.1 Air Inflation and Water Injection:

 This fender can be used with water or without water inside according to real berthing conditions.

A. With water:

1st: Inflate the fender just to bulge into a cylindrical shape with the air pressure of about 20KPa, using inflation tools and air pipe through the air valve.

2nd: Install the fenders at required using positions

3rd: Inject water into fenders, using the water valve and water pipes on both ends. The fenders will slowly sink down as more and more water is injected until the fender top is suitable to vessel boards and dock height. Turn off the water valves tightly.

4th: Restart inflation of air until the air pressure reaches to 50KPa ± 5%.

B. Without water

In case of using fenders without water, just inflate the fenders to a pressure of 50KPa ± 5%. And turn the water valve tightly off.

4.2 Fender Installation

The fenders can be installed on vessel sides as well as dock sides. Fenders are fixed with towing steel chains. One end of the chain is connected to the pulling rings on each end of fender Tyre Chain Net by shackles and swivels.  

5. Maintenance:

5.1 Inner pressure

Inner pressure should be kept among± 5% of standard working pressure (50KPa or 80KPa).

Fenders that are always used should be inspected once in every 3 months to make sure of the right pressure.

5.2 Safety and Protection

5.2.1 If the fenders are fixed with wire ropes, the ropes that directly contact the fenders should be covered by rubber sleeves. It prevents the fenders being punctured by the wires.

5.2.2 Keep the fenders away from sharp objects.

5.2.3 If the fenders are not used for long period, they should be dried and stored in a dry, shadowy and ventilated place with certain pressure.

5.2.4 The fenders should be stored away from heat sources

5.2.5 The fenders should be kept away from acid, alkali, grease and organic solvents.