Question 1

A prudent skipper treats the chart plotter as…

Accepted Answer

One aid among several, cross-checked against depth, bearings and eyes — Plotters fail, charts hold errors, GPS can be degraded. Cross-check with the echo sounder, a transit or a bearing — and look out of the boat.

Question 2

Before trusting plotter positions on a paper chart, you should check…

Accepted Answer

That both use the same horizontal datum (e.g. WGS84) — A datum mismatch can shift a plotted position by hundreds of metres. Modern charts and GPS are WGS84, but older charts carry correction notes.

Your own chart table

This lesson is part of a paid course