A requirement was stated to Brookes & Gatehouse Ltd. by B.P. Ltd. in 1962 for the measurement of velocity of approach, at the instant of impact against the fenders, of large tankers when berthing at a jetty. This information was required for operational research into the design of jetties for the new super-tankers and for ‘post-mortems’ after heavy impact. Experiments were carried out by us at the Fawley terminal of the Esso Company and the first installation was made by B.P. at their Finnart terminal in January 1963. There has been a continuing demand up to the present time by several oil companies, and a dozen jetties in different parts of the world have now been fitted with this equipment.