Radar and ARPA Manual

NAVIGATION TECHNIQUES USING RADAR AND ARPA

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indexing data, these sheets would need careful marking

with reference points for centre and north.

The recording of this navigational data is part of the

normal passage-planning process and the operator

should not look on the data as permanent and able to be

used repeatedly on future occasions without amend-

ment. It should be remembered that, in deciding on the

margin of safety lines, the tide and present vessel status,

for example, are important factors. Hence the parallel

indexing data contained on the acetate overlays should

not be used subsequently without first checking that the

data is stil ...