The two papers which follow (Jones and Ratcliffe) were presented in the course of a seminar sponsored jointly by the Institute with the Nautical Institute and held at the City of London Polytechnic on 13 December 1979. The purpose was to examine the usefulness of transponders for marine purposes. Seven papers were presented and these may be obtained at £7.50 (£5 for Members) from the Nautical Institute.

The term transponder is usually interpreted by practising mariners as the simple inband swept frequency device, called Racon, with which those mariners are most familiar. It is this concept which largely colours the mariner's views on the topic, and is perhaps the reason for the obvious reluctance to accept expanding use of transponders which is apparent in the marine industry. Their personal recollected experiences of the clutter caused by Racon and the possible problems that could result from proliferation of such beacons give justifiable cause for this hesitancy.