In order to prevent a disastrous damage induced by collision accident which might cause cargo oil spill from a struck oil tanker, the double hull system in side hull of oil tanker has been recognized as an effective countermeasures. However, when considering that ocean-going vessels are increasing not only in size but also in speed, the threat of disastrous collision accident should be further mitigated also on the responsibility of striking ships. The concepts of buffer bow have been proposed supposing its installation to fast passenger ships in the late 1960s and to large cargo vessels equipped with bulbous bow in the 1990s. RR76 panel of Shipbuilding Research Association of Japan and Ship Research Institute have started, as a joint work, to study the necessary items for the buffer bow structure since 1998. SRI has conducted a series of crush test using three kinds of simplified scale models of the buffer bow. A simple analysis method has been developed to evaluate the crashworthiness of buffer bow structure and its accuracy has been verified by comparing the results with the test and FEM calculation as well. The paper describes the performance of the buffer bow focusing on the collapse mechanism and the P/δ relation, then demonstrates the effectiveness of the present analysis method.