Binnacle
Encyclopedia
Deck (ship)
A deck is a permanent covering over a compartment or a hull of a ship. On a boat or ship, the primary deck is the horizontal structure which forms the 'roof' for the hull, which both strengthens the hull and serves as the primary working surface...
of a ship
Ship
Since the end of the age of sail a ship has been any large buoyant marine vessel. Ships are generally distinguished from boats based on size and cargo or passenger capacity. Ships are used on lakes, seas, and rivers for a variety of activities, such as the transport of people or goods, fishing,...
, generally mounted in front of the helmsman
Helmsman
A helmsman is a person who steers a ship, sailboat, submarine, or other type of maritime vessel. On small vessels, particularly privately-owned noncommercial vessels, the functions of skipper and helmsman may be combined in one person. On larger vessels, there is a separate officer of the watch,...
, in which navigational instruments are placed for easy and quick reference as well as to protect the delicate instruments. Its traditional purpose was to hold the ship's magnetic compass, mounted in gimbal
Gimbal
A gimbal is a pivoted support that allows the rotation of an object about a single axis. A set of two gimbals, one mounted on the other with pivot axes orthogonal, may be used to allow an object mounted on the innermost gimbal to remain immobile regardless of the motion of its support...
s to keep it level while the ship pitched from waves. A binnacle may be subdivided into sections and its contents typically include one or more compass
Compass
A compass is a navigational instrument that shows directions in a frame of reference that is stationary relative to the surface of the earth. The frame of reference defines the four cardinal directions – north, south, east, and west. Intermediate directions are also defined...
es and an oil lamp
Oil lamp
An oil lamp is an object used to produce light continuously for a period of time using an oil-based fuel source. The use of oil lamps began thousands of years ago and is continued to this day....
or other light source. Other devices such as a sand timer
Hourglass
An hourglass measures the passage of a few minutes or an hour of time. It has two connected vertical glass bulbs allowing a regulated trickle of material from the top to the bottom. Once the top bulb is empty, it can be inverted to begin timing again. The name hourglass comes from historically...
for estimating speed may have been stored in the binnacle as well.
The construction of many early binnacles used nails (mid 18th century), which were later discovered to cause magnetic deviation
Magnetic deviation
Magnetic deviation is the error induced in a compass by local magnetic fields, which must be allowed for, along with magnetic declination, if accurate bearings are to be calculated....
s in compass readings. As the development of the compass and understanding of magnetism
Magnetism
Magnetism is a property of materials that respond at an atomic or subatomic level to an applied magnetic field. Ferromagnetism is the strongest and most familiar type of magnetism. It is responsible for the behavior of permanent magnets, which produce their own persistent magnetic fields, as well...
progressed greater attention was given to binnacle construction to avoid compass disturbances caused by iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
.
With the introduction of iron-clad ships the magnetic deviation observed in compasses became more severe. Methods of compensation by arranging iron or magnetic objects near the binnacle were developed. In 1854 a new type of binnacle was patented by John Gray of Liverpool which directly incorporated adjustable correcting magnets on screws or rack and pinion
Rack and pinion
A rack and pinion is a type of linear actuator that comprises a pair of gears which convert rotational motion into linear motion. A circular gear called "the pinion" engages teeth on a linear "gear" bar called "the rack"; rotational motion applied to the pinion causes the rack to move, thereby...
s. This was improved again when Lord Kelvin patented in the 1880s another system of compass and which incorporated two compensating magnets. These are colloquially known as 'Kelvin's Balls' in the UK, and 'Navigator's Balls' in the US.
The ship's Binnacle List is the medical department's report of personnel at sick bay, excused from that day's duty.
Etymology
Before 18th century bittacle, through SpanSpanish language
Spanish , also known as Castilian , is a Romance language in the Ibero-Romance group that evolved from several languages and dialects in central-northern Iberia around the 9th century and gradually spread with the expansion of the Kingdom of Castile into central and southern Iberia during the...
.
bitacula, from Lat
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
. habitaculum, a little dwelling