When the energy to be absorbed by the fender has been calculated in line with the preceding, an most appropriate fender system would be selected. Each fender has corresponding performance data, and the actual performance not only depends on type of fenders, the size and the elastomer material grade, but also on several external conditions. Mostly, the performance of fenders is influenced by angular compression, by the temperature, by the compression speed, etc.
It is common practice to adopt the performance figures at rated deflection as the reference, hence, those figures should be higher than the calculated figures, taking into account the possible influences as described above.
The fender performance is usually valid only if the fender has been preconditioned by compression to the rated values, at least three times before use. If not, the first maximum compressions produced by a vessel, may well give higher than expected reactions.
Besides the energy and the above aspects, various other criteria do play a significant role as already indicated.