How to Take a 3 Point Fix When Sailing?

A three point fix is a method of fixing your position on a chart within sight of land. Three bearings are taken from landmarks on shore.  You will need a chart, a handheld bearing compass and a pencil.

To take a three point fix when you are stationary is relatively easy, because the bearings will not change in the time it takes you to take all three bearings.  When you are sailing it becomes a little tricky. The perfect three point fix, would involve the three landmarks being 120 degrees apart, thus splitting a circle equally but this is rare. Great care must be taken when selecting your land bearings.

Before you take the bearings, have a look around to see which landmarks are clearly visible and also appear on the chart. Next, make sure your bearings are as wide apart as possible, if they are too close together your fix may be less accurate.  When taking your bearings, take the bearing where the angle changes least first, i.e. bearing on the bow or stern. Your second bearing should be the second slowest to change, i.e. on the quarter.  The third bearing is the bearing that changes the fastest i.e. on the beam.

These bearings should be taken as quickly and accurately as possible, then plotted on the chart.  Remember to convert these bearings from Compass (C) to True (T). Rarely will you be fortunate enough to have all three bearing lines on the chart intersect at a single position. Typically you will end up with a triangle which we call a cocked hat. It is safest to assume your position is within this cocked hat at the closest position to any navigational danger.

This is a great skill to teach any member of crew when on a coastal passage, not only does it keep them busy but also involved in the navigation.

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