Definition
Printed in metres and decimetres on metric charts, so 27 with a small subscript 5 means 2.75 metres below chart datum, and depths over about 21 metres are shown in whole metres. The pattern of soundings is selected to show the shoalest depths in an area rather than an average, and the density reflects survey coverage. Older fathoms charts require conversion, one fathom equalling 1.8288 metres.
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