Design, Manufacturing of Pneumatic Fenders

Design of Pneumatic Rubber Fenders

Pneumatic rubber fenders is a Yokohama marine fender made of synthetic-cord reinforced rubber sheet with compressed air inside to enable it float on the water and work as the absorber between ship to ship, ship to berthing structure when they come alongside each other on the water. The fender design and selection of floating pneumatic rubber fender can be confirmed as per the maximum energy absorption of specific condition. We should calculate and compare the requirements for the energy of the following condition; the kinetic energy when the ship berthing or after berthing, the energy of relative motion of ship to ship and ship to wharf.

Ship to ship operation of pneumatic rubber fenders

Follow the flow chart which simply demonstrate the procedure of floating pneumatic rubber fenders selection.

There is a quick reference to do the floating pneumatic fenders selection tentatively as per the listed OCIMF Table. If the energy absorption of the tentative selected pneumatic rubber fender (Ef) is larger than the calculated berthing energy (E). It means that a suitable floating pneumatic rubber efnder selection has been made. If the Yokohama pneumatic fenders energy absorption capacity is less than the calculated berthing energy. The selected Yokohama type pneumatic rubber fenders should be upgraded and selected again.

OCIMF Table selection of YOKOHAMA fenders

It is a quick reference selection based on 50 Kpa ( Pneumatic 50 ) and calm condition, equivalent Displacement coefficient (C) should be calculated firstly, then make the tentatively selection as per OCIMF ship to ship transfer guide.

C= 2 x Displacement ShipA x DisplacementB / (Displacement ShipA + Displacement ShipB )

Berthing Energy Calculation of Pneumatic Rubber Fenders

The berthing energy can be calculated by the following formula.

Added Mass Coefficient

 Or

Safety Factor

A safety factor (SF) value from 1.0 to 2.0 for the berthing energy shall be considered for abnormal berthing conditions.

Eccentricity Factor

Relative Approaching

The berthing energy needs to be calculated considering weather conditions, categorized by the three conditions calm, moderate and rough; and the approaching velocity to calculate the berthing energy are asumed to be as the following table. These information are obtained from various industry reference and standards.

Ship to Quay Operation of Pneumatic Rubber Fenders

The selection and installation of pneumatic rubber fenders ( fendering ) system for a quay is determined based on several designs parameters for each ship berthing and mooring condition.

The energy can be calculated by the following formula:

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