![Soldek012](https://upload.wikimedia.org/wikipedia/commons/9/90/Soldek012.JPG)
The bilge of a ship or boat is the part of the hull that would rest on the ground if the vessel were unsupported by water. The "turn of the bilge" is the transition from the bottom of a
hull to the sides of a hull.
Internally, the bilges (usually used in the plural in this context) is the lowest
compartment
Compartment may refer to:
Biology
* Compartment (anatomy), a space of connective tissue between muscles
* Compartment (chemistry), in which different parts of the same protein serves different functions
* Compartment (development), fields of cells ...
on a
ship
A ship is a large watercraft that travels the world's oceans and other sufficiently deep waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research, and fishing. Ships are generally distinguished ...
or
seaplane
A seaplane is a powered fixed-wing aircraft capable of takeoff, taking off and water landing, landing (alighting) on water.Gunston, "The Cambridge Aerospace Dictionary", 2009. Seaplanes are usually divided into two categories based on their tec ...
, on either side of the
keel
The keel is the bottom-most longitudinal structural element on a vessel. On some sailboats, it may have a hydrodynamic and counterbalancing purpose, as well. As the laying down of the keel is the initial step in the construction of a ship, in Br ...
and (in a traditional wooden vessel) between the floors.
The first known use of the word is from 1513.
Bilge water
The word is sometimes also used to describe the water that collects in this area. Water that does not drain off the side of the deck or through a hole in the hull, typically via a
scupper
A scupper is an opening in the side walls of a vessel or an open-air structure, which allows water to drain instead of pooling within the bulwark or gunwales of a vessel, or within the curbing or walls of a building.
There are two main kinds of s ...
, drains down into the ship into the bilge. This water may be from rough seas, rain, leaks in the hull or
stuffing box
A stuffing box or gland package is an assembly which is used to house a gland seal. It is used to prevent leakage of fluid, such as water or steam, between sliding or turning parts of machine elements.
Components
A stuffing box of a sailing boat ...
, or other interior spillage. The collected water must be pumped out to prevent the bilge from becoming too full and threatening to sink the ship.
Bilge water can be found aboard almost every vessel. Depending on the ship's design and function, bilge water may contain water,
oil
An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturated ...
,
urine
Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excretion, excreted from the body through the urethra.
Cel ...
,
detergents,
solvents
A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for p ...
, chemicals,
pitch, particles, and other materials.
By housing water in a compartment, the bilge keeps these liquids below decks, making it safer for the crew to operate the vessel and for people to move around in heavy weather.
Regulations
Discharge of bilge liquids is regulated for commercial vessels under
Marpol Annex I Marpol Annex I is the first implementation made by Marpol 73/78, one of the most important international marine environmental conventions. The convention was designed to minimize pollution of the seas from ships. The objective of the convention is ...
.
Caribbean Princess
MS ''Caribbean Princess'' is a modified owned and operated by Princess Cruises, with a capacity of over 3,600 passengers, the largest carrying capacity in the Princess fleet until June 2013 when the new , another Princess ship superseded its rec ...
was fined 40 million USD for dumping bilge into the ocean in 2016. Bilge water can be offloaded at a port, or treated to remove pollutants.
Even treated bilge water is harmful to the environment, all the way up the food chain. The
European Maritime Safety Agency
The European Maritime Safety Agency (EMSA) is a European Union agency charged with reducing the risk of maritime accidents, marine pollution from ships and the loss of human lives at sea by helping to enforce the pertinent EU legislation. It is ...
tracks bilge dumping by satellite.
There is an estimated 3000 cases of illegal bilge dumping per year in Europe.
Bilge maintenance
![Sentina](https://upload.wikimedia.org/wikipedia/commons/2/2c/Sentina.PNG)
Methods of removing water from bilges have included
bucket
A bucket is typically a watertight, vertical Cylinder (geometry), cylinder or Truncation (geometry), truncated Cone (geometry), cone or square, with an open top and a flat bottom, attached to a semicircular carrying handle (grip), handle called ...
s and
pump
A pump is a device that moves fluids (liquids or gases), or sometimes slurries, by mechanical action, typically converted from electrical energy into hydraulic energy. Pumps can be classified into three major groups according to the method they u ...
s. Modern vessels usually use electric
bilge pump
A bilge pump is a water pump used to remove bilge water. Since fuel can be present in the bilge, electric bilge pumps are designed to not cause sparks. Electric bilge pumps are often fitted with float switches which turn on the pump when the bilg ...
s controlled by automated bilge switches. Bilge coatings are applied to protect the bilge surfaces. The water that collects is often noxious, and "bilge water" or just "bilge" has thus become a derogatory colloquial term used to refer to something bad, fouled, or otherwise offensive.
Bilges may contain partitions to damp the rush of water from side to side and fore and aft to avoid destabilizing the ship due to the
free surface effect
The free surface effect is a mechanism which can cause a watercraft to become unstable and capsize.
It refers to the tendency of liquids — and of unbound aggregates of small solid objects, like seeds, gravel, or crushed ore, whose behavior ap ...
. Partitions may contain
limber hole
A limber hole is a drain hole through a frame or other structural member of a boat designed to prevent water from accumulating against one side of the frame, and allowing it to drain toward the bilge.
Limber holes are common in the bilges of woo ...
s to allow water to flow at a controlled rate into lower compartments.
Cleaning the bilge and bilge water is also possible using "passive" methods such as
bioremediation
Bioremediation broadly refers to any process wherein a biological system (typically bacteria, microalgae, fungi, and plants), living or dead, is employed for removing environmental pollutants from air, water, soil, flue gasses, industrial effluent ...
, which uses bacteria or
archaea
Archaea ( ; singular archaeon ) is a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaebac ...
to break down the
hydrocarbons
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ex ...
in the bilge water into harmless byproducts. Of the two general schools of thought on bioremediation, the one that uses beneficial microbes local to the bilge is regarded as being more "green" because it does not introduce foreign bacteria to the waters that the vessel sits in or travels through. But archaea that are non-indigenous also can be used and discharged, since the archaea will die off anyway, leaving only local indigenous microbes remaining.
Bilge alarm
Large commercial vessels need
bilge alarm
The bilge of a ship or boat is the part of the hull that would rest on the ground if the vessel were unsupported by water. The "turn of the bilge" is the transition from the bottom of a hull to the sides of a hull.
Internally, the bilges (us ...
s to notify the crew how much and where the bilge water is rising. These bilge alarms are electric devices that are also designed to detect leakages in the ship early before major damage is done to the vessel.
Oil content meter
An oil content meter (OCM) is an integral part of all oily water separator (OWS) systems. Oil content meters are also sometimes referred to as oil content monitors, bilge alarms, or bilge monitors.
OCM technology
The OCM continuously monitors ...
s are sometimes referred to as bilge alarms.
"Bilge rat"
The term "bilge rat" typically refers to members of a ship's crew who work in the bowels of the vessel, where rats would sometimes breed.
The term was sometimes used in the
Royal Navy
The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against F ...
to describe
stokers who shovelled coal into the boilers of steam-powered warships.
It is utilized as an insult,
and often employed as such by writers of
pirate fiction
In English-speaking popular culture, the modern pirate stereotype owes its attributes mostly to the imagined tradition of the 18th century Caribbean pirate sailing off the Spanish Main and to such celebrated 20th century depictions as Cap ...
.
See also
*
Basement
A basement or cellar is one or more floors of a building that are completely or partly below the ground floor. It generally is used as a utility space for a building, where such items as the furnace, water heater, breaker panel or fuse box, ...
*
Sump
A sump is a low space that collects often undesirable liquids such as water or chemicals. A sump can also be an infiltration basin used to manage surface runoff water and recharge underground aquifers. Sump can also refer to an area in a cave ...
Notes
References
{{Sailing ship elements
Naval architecture
Ship compartments
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