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A mooring is any permanent structure to which a vessel may be secured. Examples include
quay A wharf, quay (, also ), staith, or staithe is a structure on the shore of a harbour or on the bank of a river or canal where ships may dock to load and unload cargo or passengers. Such a structure includes one or more berths ( mooring locatio ...
s,
wharf A wharf, quay (, also ), staith, or staithe is a structure on the shore of a harbour or on the bank of a river or canal where ships may dock to load and unload cargo or passengers. Such a structure includes one or more berths ( mooring locati ...
s, jetties,
pier Seaside pleasure pier in Brighton, England. The first seaside piers were built in England in the early 19th century.">England.html" ;"title="Brighton, England">Brighton, England. The first seaside piers were built in England in the early 19th ...
s, anchor
buoy A buoy () is a floating device that can have many purposes. It can be anchored (stationary) or allowed to drift with ocean currents. Types Navigational buoys * Race course marker buoys are used for buoy racing, the most prevalent form of y ...
s, and mooring buoys. A ship is secured to a mooring to forestall free movement of the ship on the water. An ''anchor mooring'' fixes a vessel's position relative to a point on the bottom of a waterway without connecting the vessel to shore. As a verb, ''mooring'' refers to the act of attaching a vessel to a mooring. The term likely stems from the
Dutch Dutch commonly refers to: * Something of, from, or related to the Netherlands * Dutch people () * Dutch language () Dutch may also refer to: Places * Dutch, West Virginia, a community in the United States * Pennsylvania Dutch Country People E ...
verb ''meren'' (to ''moor''), used in English since the end of the 15th century.


Permanent anchor mooring

These moorings are used instead of temporary anchors because they have considerably more holding power, for example because of lesser damage to the marine environment, and are convenient. Where there is a row of moorings they are termed a tier. They are also occasionally used to hold floating docks in place. There are several kinds of moorings:


Swing moorings

Swing moorings also known as simple or single-point moorings, are the simplest and most common kind of mooring. A swing mooring consists of a single anchor at the bottom of a waterway with a rode (a rope, cable, or chain) running to a float on the surface. The float allows a vessel to find the rode and connect to the anchor. These anchors are known as swing moorings because a vessel attached to this kind of mooring swings in a circle when the direction of wind or tide changes. For a small boat (e.g. 22' / 6.7 m sailing yacht), this might consist of a heavy weight on the seabed, a 12 mm or 14 mm rising chain attached to the "anchor", and a bridle made from 20 mm nylon rope, steel cable, or a 16 mm combination steel wire material. The heavy weight (anchor) should be a dense material. Old rail wagon wheels are used in some places (e.g. Clontarf, Dublin, Ireland) for this purpose. In some harbours (e.g. Dun Laoghaire, Ireland), very heavy chain (e.g. old ship anchor chain) may be placed in a grid pattern on the sea bed to ensure orderly positioning of moorings. Ropes (particularly for marker buoys and messenger lines) should be "non floating" to reduce likelihood of a boat's propeller being fouled by one.


Pile moorings

Pile moorings are poles driven into the bottom of the waterway with their tops above the water. Vessels then tie mooring lines to two or four piles to fix their position between those piles. Pile moorings are common in
New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island coun ...
but rare elsewhere. While many mooring buoys are privately owned, some are available for public use. For example, on the
Great Barrier Reef The Great Barrier Reef is the world's largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over over an area of approximately . The reef is located in the Coral Sea, off the coast of Queensland, A ...
off the
Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...
n coast, a vast number of public moorings are set out in popular areas where boats can moor. This is to avoid the massive damage that would be caused by many vessels
anchor An anchor is a device, normally made of metal , used to secure a vessel to the bed of a body of water to prevent the craft from drifting due to wind or current. The word derives from Latin ''ancora'', which itself comes from the Greek � ...
ing. There are four basic types of permanent anchors used in moorings: *Dead weights are the simplest type of anchor. They are generally made as a large concrete block with a rode attached which resists movement with sheer weight; and, to a small degree, by settling into the substrate. In New Zealand old railway wheels are sometimes used. The advantages are that they are simple and cheap. A dead weight mooring that drags in a storm still holds well in its new position. Such moorings are better suited to rocky bottoms where other mooring systems do not hold well. The disadvantages are that they are heavy, bulky, and awkward. *Mushroom anchors are the most common anchors and work best for softer seabeds such as mud,
sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class ...
, or
silt Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water. Silt usually has a floury feel ...
. They are shaped like an upside-down mushroom which can be easily buried in mud or silt. The advantage is that it has up to ten times the holding-power-to-weight ratio compared to a dead weight mooring; disadvantages include high cost, limited success on rocky or pebbly substrates, and the long time it takes to reach full holding capacity. *Pyramid anchors are pyramid-shaped anchors, also known as Dor-Mor anchors. They work in the upside-down position with the apex pointing down at the bottom such that when they are deployed, the weight of wider base pushes the pyramid down digging into the floor. As the anchors are encountered with lateral pulls, the side edges or corners of the pyramids will dig deeper under the floor, making them more stable. *Screw-in moorings are a modern method. The anchor in a screw-in mooring is a shaft with wide blades spiraling around it so that it can be screwed into the substrate. The advantages include high holding-power-to-weight ratio and small size (and thus relative cheapness). The disadvantage is that a diver is usually needed to install, inspect, and maintain these moorings. *Multiple anchor mooring systems use two or more (often three) light weight temporary-style
anchor An anchor is a device, normally made of metal , used to secure a vessel to the bed of a body of water to prevent the craft from drifting due to wind or current. The word derives from Latin ''ancora'', which itself comes from the Greek � ...
s set in an equilateral arrangement and all chained to a common center from which a conventional rode extends to a mooring buoy. The advantages are minimized mass, ease of deployment, high holding-power-to-weight ratio, and availability of temporary-style anchors.


Mooring to a shore fixture

A vessel can be made fast to any variety of shore fixtures from trees and rocks to specially constructed areas such as
pier Seaside pleasure pier in Brighton, England. The first seaside piers were built in England in the early 19th century.">England.html" ;"title="Brighton, England">Brighton, England. The first seaside piers were built in England in the early 19th ...
s and
quays A wharf, quay (, also ), staith, or staithe is a structure on the shore of a harbour or on the bank of a river or canal where ships may dock to load and unload cargo or passengers. Such a structure includes one or more berths (mooring locatio ...
. The word pier is used in the following explanation in a generic sense. Mooring is often accomplished using thick ropes called ''mooring lines'' or ''
hawser Hawser () is a nautical term for a thick cable or rope used in mooring or towing a ship. A hawser passes through a hawsehole, also known as a cat hole, located on the hawse. The American Heritage Dictionary of the English Language, third editi ...
s''. The lines are fixed to deck fittings on the vessel at one end and to fittings such as bollards, rings, and cleats on the other end. Mooring requires cooperation between people on a pier and on a vessel. Heavy mooring lines are often passed from larger vessels to people on a mooring by smaller, weighted heaving lines. Once a mooring line is attached to a
bollard A bollard is a sturdy, short, vertical post. The term originally referred to a post on a ship or quay used principally for mooring boats. It now also refers to posts installed to control road traffic and posts designed to prevent automotive ...
, it is pulled tight. Large ships generally tighten their mooring lines using heavy machinery called ''mooring winches'' or ''capstans''. The heaviest cargo ships may require more than a dozen mooring lines. Small vessels can generally be moored by four to six mooring lines. Mooring lines are usually made from manila rope or a synthetic material such as
nylon Nylon is a generic designation for a family of synthetic polymers composed of polyamides ( repeating units linked by amide links).The polyamides may be aliphatic or semi-aromatic. Nylon is a silk-like thermoplastic, generally made from pet ...
. Nylon is easy to work with and lasts for years, but it is highly
elastic Elastic is a word often used to describe or identify certain types of elastomer, elastic used in garments or stretchable fabrics. Elastic may also refer to: Alternative name * Rubber band, ring-shaped band of rubber used to hold objects togethe ...
. This elasticity has advantages and disadvantages. The main advantage is that during an event, such as a high wind or the close passing of another ship, stress can be spread across several lines. However, should a highly stressed nylon line break, it may part catastrophically, causing ''snapback'', which can fatally injure bystanders. The effect of ''snapback'' is analogous to stretching a rubber band to its breaking point between your hands and then suffering a stinging blow from its suddenly flexing broken ends. Such a blow from a heavy mooring line carries much more force and can inflict severe injuries or even sever limbs. Mooring lines made from materials such as
Dyneema Ultra-high-molecular-weight polyethylene (UHMWPE, UHMW) is a subset of the thermoplastic polyethylene. Also known as high-modulus polyethylene, (HMPE), it has extremely long chains, with a molecular mass usually between 3.5 and 7.5 million amu. T ...
and
Kevlar Kevlar (para-aramid) is a strong, heat-resistant synthetic fiber, related to other aramids such as Nomex and Technora. Developed by Stephanie Kwolek at DuPont in 1965, the high-strength material was first used commercially in the early 1970s a ...
have much less elasticity and are therefore much safer to use. However, such lines do not float on water and they do tend to sink. In addition, they are relatively more expensive than other sorts of line. Some ships use
wire rope Steel wire rope (right hand lang lay) Wire rope is several strands of metal wire twisted into a helix forming a composite '' rope'', in a pattern known as ''laid rope''. Larger diameter wire rope consists of multiple strands of such laid rope in ...
for one or more of their mooring lines. Wire rope is hard to handle and maintain. There is also risk associated with using wire rope on a ship's stern in the vicinity of its propeller. Mooring lines and hawsers may also be made by combining wire rope and synthetic line. Such lines are more elastic and easier to handle than wire rope, but they are not as elastic as pure synthetic line. Special safety precautions must be followed when constructing a combination mooring line. The two-headed mooring
bitts Bitts are paired vertical wooden or metal posts mounted either aboard a ship or on a wharf, pier or quay. The posts are used to secure mooring lines, ropes, hawsers, or cables. Bitts aboard wooden sailing ships (sometime called cable-bitts) w ...
is a fitting often-used in mooring. The rope is hauled over the bitt, pulling the vessel toward the bitt. In the second step, the rope is tied to the bitt, as shown. This tie can be put and released very quickly. In quiet conditions, such as on a lake, one person can moor a 260-tonne ship in just a few minutes. Quick release mooring hooks provide an alternative method of securing the rope to the quay: such a system "greatly reduces the need for port staff to handle heavy mooring ropes … means staff have to spend less time on exposed areas of the dock, and educesthe risk of back injuries from heavy lifting". The
Oil Companies International Marine Forum Oil Companies International Marine Forum (OCIMF) is a voluntary association of oil companies having an interest in the shipment and terminalling of crude oil, oil products, petrochemicals and gas, and includes companies engaged in offshore marine o ...
recommend the use of such hooks in oil and gas terminals. The basic rode system is a line, cable, or chain several times longer than the depth of the water running from the anchor to the mooring buoy, the longer the rode is the shallower the angle of force on the anchor (it has more scope). A shallower scope means more of the force is pulling horizontally so that ploughing into the substrate adds holding power but also increases the swinging circle of each mooring, so lowering the density of any given mooring field. By adding weight to the bottom of the rode, such as the use of a length of heavy chain, the angle of force can be dropped further. Unfortunately, this scrapes up the substrate in a circular area around the anchor. A buoy can be added along the lower portion of rode to hold it off the bottom and avoid this issue.


Other types

Non-line mooring ("hands-free") is used where pier time is highly valuable, and includes
suction cup A suction cup, also known as a sucker, is a device or object that uses the negative Pressure#Fluid pressure, fluid pressure of air or water to adhere to Porosity, nonporous surfaces, creating a Vacuum, partial vacuum. Suction cups are peripher ...
s or
magnet A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nicke ...
s. It can also be used between ships.


Mediterranean mooring

Mediterranean mooring, also known as "med mooring" or "Tahitian mooring", is a technique for mooring a vessel to pier. In a Mediterranean mooring the vessel sets a temporary anchor off the pier and then approaches the pier at a perpendicular angle. The vessel then runs two lines to the pier. Alternatively, simple moorings may be placed off the pier and vessels may tie to these instead of setting a temporary anchor. The advantage of Mediterranean mooring is that many more vessels can be connected to a fixed length of pier as they occupy only their width of pier rather than their length. The disadvantages of Mediterranean mooring are that it is more likely to result in collisions and that it is not practical in deep water or in regions with large tides.


Travelling/running mooring

A mooring used to secure a small boat (capable of being beached) at sea so that it is accessible at all tides. Making a Travelling Mooring involves (1) the sinking of a heavy weight to which a block (
pulley A pulley is a wheel on an axle or shaft that is designed to support movement and change of direction of a taut cable or belt, or transfer of power between the shaft and cable or belt. In the case of a pulley supported by a frame or shell that ...
wheel) is attached at a place where the sea is sufficiently deep at low tide, (2) fitting a block / pulley wheel to a rock or secure point above the high tide mark, and (3) running a heavy rope with marker buoy between these blocks. Mooring involves (a) beaching the boat, (b) drawing in the mooring point on the line (where the marker buoy is located), (c) attaching to the mooring line to the boat, and (d) then pulling the boat out and away from the beach so that it can be accessed at all tides.


Canal mooring

A mooring used to secure a
Narrowboat A narrowboat is a particular type of canal boat, built to fit the narrow locks of the United Kingdom. The UK's canal system provided a nationwide transport network during the Industrial Revolution, but with the advent of the railways, commer ...
(capable of traversing narrow UK canals and narrow locks) overnight, during off boat excursions or prolonged queuing for canal lock access. Water height with minimal exceptions, remain constant (not-tidal); there is water height variance in close proximity to
locks Lock(s) may refer to: Common meanings *Lock and key, a mechanical device used to secure items of importance *Lock (water navigation), a device for boats to transit between different levels of water, as in a canal Arts and entertainment * ''Lock ...
. Types of canal moorings: Mooring pin (boat operator supplied) driven into the ground between the edge of the canal and the
Towpath A towpath is a road or trail on the bank of a river, canal, or other inland waterway. The purpose of a towpath is to allow a land vehicle, beasts of burden, or a team of human pullers to tow a boat, often a barge. This mode of transport w ...
with a mooring-line rope to the boat. Mooring hook (boat operator supplied) placed on the (permanent) canal-side rail with either (boat operator supplied) rope or chain-and-rope to the boat. Mooring ring (permanent) affixed between the edge of the canal and the tow path, with (boat operator supplied) rope to the boat. Mooring bollard (permanent) affixed canal-side on lock-approaches for the short-term mooring of advancing boats and lock-side to assist in ascent and descent.


Mooring line materials

; Regular mooring lines *
Sisal Sisal (, ) (''Agave sisalana'') is a species of flowering plant native to southern Mexico, but widely cultivated and naturalized in many other countries. It yields a stiff fibre used in making rope and various other products. The term sisal may ...
*
Hemp Hemp, or industrial hemp, is a botanical class of '' Cannabis sativa'' cultivars grown specifically for industrial or medicinal use. It can be used to make a wide range of products. Along with bamboo, hemp is among the fastest growing plants ...
*
Steel wire Steel wire rope (right hand lang lay) Wire rope is several strands of metal wire twisted into a helix forming a composite ''rope'', in a pattern known as ''laid rope''. Larger diameter wire rope consists of multiple strands of such laid rope in a ...
*
Polyethylene Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging ( plastic bags, plastic films, geomembranes and containers including b ...
*
Polypropylene Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications. It is produced via chain-growth polymerization from the monomer propylene. Polypropylene belongs to the group of polyolefins a ...
*
Polyester Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include natura ...
(e.g., used for deepsea mooring of offshore platforms) *
Nylon Nylon is a generic designation for a family of synthetic polymers composed of polyamides ( repeating units linked by amide links).The polyamides may be aliphatic or semi-aromatic. Nylon is a silk-like thermoplastic, generally made from pet ...
*
Chain A chain is a serial assembly of connected pieces, called links, typically made of metal, with an overall character similar to that of a rope in that it is flexible and curved in compression but linear, rigid, and load-bearing in tension. ...
;High-performance mooring lines * HMPE (floating) *
Aramid Aramid fibers, short for aromatic polyamide, are a class of heat-resistant and strong synthetic fibers. They are used in aerospace and military applications, for ballistic-rated body armor fabric and ballistic composites, in marine cordage, mar ...
(heat resistant) (including
Kevlar Kevlar (para-aramid) is a strong, heat-resistant synthetic fiber, related to other aramids such as Nomex and Technora. Developed by Stephanie Kwolek at DuPont in 1965, the high-strength material was first used commercially in the early 1970s a ...
)


See also

* * * * *


References


External links


IACS Unified Requirement A: Mooring and AnchoringFind moorings"Docking The World's Great Liners"
''Popular Mechanics'', May 1930, article on docking large ships in the first half of the 20th century
ShipServ Pages Mooring RopesVideo on Canal MooringAnchor Chain and Mooring Fittings
{{Seamanship Boats Nautical terminology