However much opinions may vary as to the proper way to treat the problems raised by the use of radar, there is no doubt that something must be done to help navigators resolve them. The International Conference on Safety of Life at Sea held in London in June 1948 saw fit to declare in its Recommendation No. 19 that the possession of radar in no way relieves a vessel from the obligation of strictly observing the requirements laid down in the Rules for Preventing Collisions, and in particular with Rules 15 and 16 (sound signals in fog, moderate speed in fog, &c). It is common knowledge that navigators have not found constructive guidance in this text, and accidents have multiplied. It has been argued that the increase in accidents has not been proportionately as great as the increase in tonnage, but the argument is not very weighty. In the first place, accidents have become particularly serious because of the size and crossing speed of ships; and in any case it is a poor consolation to masters anxious to observe the Rules, but not quite certain how to do so, to be told that there is no cause for anxiety as there are not as many accidents as all that. This argument, even if it does not actually discourage navigators anxious to observe the Rules still runs the risk of making hesitant navigators err on the wrong side. It is therefore necessary to do something, and the first thing seems to be to state the problem concisely.