Deliberate Error

Direct reckoning (DR) positions are almost certainly wrong, but how wrong? When approaching a featureless coast, or a hazard such as a reef, introduce an error of your own choosing and steer a course which avoids the danger, or tells you which way to turn when you sight land.

The Dutch coastline is mostly featureless dyke. Sailing from Lowestoft or Harwich towards Ijmuiden you could be almost anywhere, until you spot the harbour piers. Select a landfall a few miles south or north, so that when you see land you know which way to turn to reach Ijmuiden (as shown in Figure 5.6). Aim off rather more than your maximum expected error. If you expect to be 10 miles off course when you reach land, then aim off 11 miles.

5.6 Landfall by Aiming Off

0 0

Post a comment