USE A TRANSIT

Those who regularly read or watch MBY's 'How To' series will know that I often refer to transits.

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So, what exactly are they? A transit is an alignment of two fixed objects that are either marked on a chart or visible from your boat, which you can use to aid navigation or to help manoeuvre your boat in confined waters.

On charts, they are usually marked with a line helping you to identify which two objects have been selected. Then you need to spot them from your boat so you can use them as intended. Sometimes this can be difficult, especially if you have no reference images of what it is you are looking for. This is where charts and pilot books can be a great help. However, on most modern plotters, if you hover over the marks with the cursor, it will either give further details of what it is you are looking for or even a visual image of the object itself. Transits are described as ‘Closed’ when the objects are exactly in line, or ‘Open’ when there is a gap between them. Both are useful and allow you to judge your boat's movement relative to the land.

Transits tend to come in three types: charted daylight only ones, which are often used to aid entering or leaving a harbour; charted lit ones, which in theory can be used by day or night but are most useful in the dark; and ‘personal’ ones, which you can make up as you go. For instance, fishermen often mark their favourite spot by lining up two items on the shore, for example, a church spire in the background and an easily identifiable beachfront house in the foreground. This type of usage has declined now that GPS has become so accurate, but I still find them invaluable for monitoring my boat's movement, especially in congested harbours and marinas when there is a strong tide or wind pushing the boat around.