Despite the fact that there is a large number of plotting aids available there must be many vessels in which radar plotting for anti-collision purposes remains a drawing exercise (transferred plotting), or is not attempted because it is believed to be a process too lengthy for the exigencies of practical work.

Quoting J. R. Webster of the Board of Trade—‘Most of the collisions which have occurred have been in conditions when there were no other ships in the close-quarter situation, and in my opinion the relative display is better for judging the degree of collision risk in this case, with a simple plot to ascertain the effective avoiding action’.

Believing this to be so, the following suggestion is made for simplifying plotting procedure.

The information used in the plot should not require conversion in the time-distance-speed sense and this should apply to the information derived from the plot. The plot should enable the navigator to answer these questions:

i. Will a collision take place if present courses and speeds are maintained ?

ii. What will be the distance off at nearest approach of the target even if there is no collision ?

iii. What alteration of course and/or speed is required in order that this distance off can be increased to some safe value ?

iv. What time is available for action ?