hand bearing compass


The hand compass is a compact magnetic compass, preferably capable of one-hand use  and fitted with a sighting device to observe a precise bearing.

This compass should be rugged and waterproof – ideal for use on all boats and all conditions.

In the hands of a navigator it can be used to get an bearing or heading to a given target or to determine a location.

Hand or sighting compasses often include a prismatic sight with the additional precision offered by the sighting arrangement.

History and use
Small portable compasses fitted with mechanical sighting devices have existed for hundreds of years, the first one-hand compass for land use with a sighting device appeared around 1885. Hand compasses were soon widely employed in the practice of forestry, geology, archaeology, speleology, preliminary cartography and land surveying. However the use of a handbearing compass at sea is considered essential by many navigators on small and medium size vessels.


By using a hand compass in combination with conspicuous landmarks ashore that are charted on admiralty charts a ship can determine a position accurately at sea

In recent years the use of the GPS, or Global Positioning System receivers has brought a convenience to navigation at sea and on land. However, whilst GPS can give a position described to many decimal places, a three bearing fix on a chart can be relied upon to be free of electrical or external interference by other parties.

The marine hand compass has been used by small-boat or inshore sailors since the early 1920s to keep a running course or to record precise bearings to landmarks on shore in order to determine position via the resection technique.Instead of a magnetized needle or disc, most hand bearing compasses feature liquid damping with a floating card design (a magnetized, degreed float or dial atop a jeweled pivot bearing).

Equipped with a viewing prism, the hand bearing compass allows instant reading of forward bearings from the user to an object or vessel, and some provide the reciprocal bearing as well. Modern examples of marine hand bearing compasses include the Plastimo Iris 50 which has photoluminescent degree dial for use in low light or darkness.

Unlike use ashore, the hand bearing compass at sea is very useful for anti collision work. For example, if the compass bearing of another vessel does not appreciably change and the distance is reducing, it can be assumed that a close quarter or collision situation is developing. Here is a video that explains that in greater detail.

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