Instrument	:	Station Pointer (Protractor)
Manufacturer	:	Kelvin Hughes Co
Country of origin	:	U.K.
Manufacturing year	:	unknown

I've obtained this instrument in 1996 together with the Warren Knight station pointer in my collection. The instrument is used for coastal navigation using a sextant and was invented in 1801 by Joseph Huddart, a U.S. naval captain. This instrument, also referred to as a three-arm protractor, is composed of a circular scale connected to three arms. The centre arm is fixed, while the outer two can be adjusted to an angle previously measured with a sextant.

In coastal navigation the vessel's coordinates can be established by measuring two horizontal angles between three coastal objects. After setting the legs of the station pointer to these angles (adjustment is done with two drum micrometers) it can be laid on a map showing the same objects. With the legs running over the objects on the map, the center of the instrument will be your position in it.