Vertical installation of Super Arch rubber fenders

Vertical installation of Super Arch Rubber fenders

(1) Installation of V-type rubber fender

As shown in below figure, V-type rubber fenders without fender panels do not contact at the full length for certain vessel positions, and rubber fenders can perform only in the length contacted. It is necessary to estimate the minimum contact length from the minimum deck height, draft, tidal level, etc. and select the length such that the effective berthing energy Eb can be absorbed. This phenomenon is called partial compression, and the performance can be evaluated using equation with (Energy absorption by partial compression)=(Energy absorption per meter)×(Contact length).

In the case of rubber fenders with a constant cross-section (for example, V-type rubber fenders) for which the performance can be modified by changing the length, if the length is shorter than the height, the length ratio is affected by both the ends. The length ratio in this case may not correspond to the performance being proportional to the length. The contact length of a rubber fender relates to not only the length of the rubber fender but also the installation position. The installation considerations for V-type rubber fenders are listed as follows, and above figure provides an explanatory view of the aspects to be considered.

・ The flare of a large vessel should not contact the edge of the quay, even when the rubber fender is compressed.

・ It is desirable that the top head of fender is always visible and not be submerged in water.

・ The necessary concrete coverage should be secured over the anchor bolts

・ The effective berthing energy must be absorbed by the length in contact with the rubber fenders

As shown in above figure, when the flare of a large vessel comes in contact with a vertically installed V-type rubber fender, the fender is subjected to vertical angular compression. Generally, the angular performance of V-type rubber fenders described in catalogue is the angular performance in the width direction, and the longitudinal angular performance is often not defined because it changes depending on the length of the rubber fender. In such a case, the performance can be determined in the following manner.

The performance curve of the energy absorption EA of a V-type rubber fender is defined as in equation with EA = f(x）Continuous functions such as polynomials as a function of the deflection x by

considering a polynomial function or numerical values in a table.

If variables are defined as shown in Fig (Angular compression by hull flare to V-type rubber fender)for the condition shown in Fig. (Considerations for vertical installation of V-type rubber fender), the angular reaction force of a rubber fender can be estimated using equation (below) by integrating the reaction force of the compressed part. 

Here,

EAθ : Energy absorption at simulated angular compression (kN×m)

Ly : Contact length (m)

D : Design deflection of V-type fender (m)

θ : Flare angle

y : Variable from fender top (m)

The maximum reaction force to the quay is larger when the entire surface is compressed at an angle of 0°; thus, a reaction force with an angle of 0° is used. 

Since the amount of compression by the hull flare, as calculated using equation (above), is small, the fender may not be able to absorb the effective berthing energy of a large vessel. In such a case, horizontal installation or alternate vertical and horizontal installation of V-type rubber fenders can be realized. Alternatively, rubber fenders with fender plates may be used.

(2) Installation of rubber fender with panel

Even in the case of rubber fenders with panels, it is necessary to perform a geometric investigation of the minimum vessel freeboard, draft and lowest tidal level. In such cases, the panel, chain, etc. need to be considered in the system, as described in the next section.