When plotting a series of radar bearings to determine the other vessel's course and speed, any alteration of own course or speed during the plotting interval greatly complicates the construction of a relative plot. A continuous alteration would make it very difficult to construct a plot at all. As far as the other vessel is concerned, should she also have radar, your echo on her PPI will not follow a straight line and she will be able to draw no conclusions regarding your course and speed. There is therefore no doubt that, when using radar for anticollision purposes, alterations of course and speed should, as far as circumstances permit, be as few as possible and each should be bold. Let us consider what is ‘bold’, treating alterations of course and speed separately, and remembering that it is necessary for the other vessel, if she is using radar, to appreciate that you have altered course as early as possible after your action.