Navigation and Chart work - Chart Plotting Instruments

Navigation dividers

Navigation dividers are designed to be used one handed (you may Navigational dividers. need the other to hold on to your chart table!), and to be opened with the points crossed. Do not be frightened of pressing the points in to the chart, this will help you to hold them steady and to measure distances more accurately, just do not press them in so hard you damage the chart.

Also if you are practicing at home place a protective surface between the chart and your varnished dining room table!


You will need some sort of navigational plotter. By far the most popular tool for this is a Breton or Portland Plotter, they are essentially the Portland or breton Plotter.same thing. A rectangular ruler with a rotating compass rose fixed in the center. They are used for plotting and measuring directions on nautical charts.

If you are familiar with the use of parallel rules, a Douglass Protractor or two set squares for plotting bearings by all means continue to to so, there are many different ways of working on charts and they all have their place.

Because it was what I first learnt with, I used parallel rules until I took an instructor's course where a plotter was used, as soon as I realised how much faster I could work, I switched to a Breton Plotter.


A good supply of 2B pencils are essential. 2B pencils are soft enough so they do not damage the chart and will keep a point for a reasonable period.

Many navigators now use a propelling type pencil as they do not require sharpening, if you choose this route, make sure it is not so hard that the lines you draw on the chart are too faint to be seen in poor lighting.


Choose an eraser that is soft and will not remove the chart surface, there are some that are slightly crumbly when used and they can be ideal.

Pencil sharpener

As it will be used frequently, select one that retains the sharpening debris and dry to keep it dry. In the salty atmosphere on a yacht, the blades frequently rust and do not last long.


A basic calculator that can be purchased for a couple of pounds can be useful for calculating the time of a passage.

Note pad

Spare paper for calculating on or recording bearings is useful.

Sealable food bags

A supply of sealable food bags or a hill walker's map case are essential if you wish to take a passage plan or pilotage notes on deck in wet weather. If the paper is not protected all your hard work will turn to paper-mâché in a few minutes.

Small towel

Always have a small towel handy so that when navigating in wet conditions, use it to dry off each time you visit the chart table so that you do not drip on the charts. There is nothing that wrecks charts faster than getting them wet and working on them, any point where you rub on the chart will probably remove the surface and the features.


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Mailspeed Marine
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