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A mooring is any permanent structure to which a vessel may be secured. Examples include
quay A wharf, quay (, also ), or staith(e) 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 Berth (moorings), berths (Moorin ...

quay
s,
wharf A wharf, quay (, also ), or staith(e) is a structure on the shore of a harbour A harbor (American English American English (AmE, AE, AmEng, USEng, en-US), sometimes called United States English or U.S. English, is the set of varie ...

wharf
s,
jetties File:Seebrücke Swakopmund, Namibia.jpg, Aerial view of a jetty at Swakopmund, Namibia (2017) A jetty is a structure that projects from land out into water. It may also refer more specifically to a walkway accessing the centre of an enclosed wa ...

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 ...

pier
s, anchor
buoy A buoy (, North America more commonly, but not exclusively ) is a Buoyancy, floating device that can have many purposes. It can be anchored (stationary) or allowed to drift with ocean currents. The etymology of the word is disputed. Types Na ...

buoy
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 language , spoken in Belgium (also referred as ''flemish'') Dutch may also refer to:" Castle * Dutch Castle Places * ...
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 ''Aotearoa'' (; commonly pronounced by English English usually refers to: * English language English is a West Germanic languages, West Germanic language first spoken in History of Anglo-Saxon Engl ...

New Zealand
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 A coral reef is an underwater ecosystems, ecosystem characterized by reef-building corals. Reefs are formed of Colony (biology), colonies of coral polyp (zoology), polyps held tog ...

Great Barrier Reef
off the
Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Australia
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 connect a Watercraft, vessel to the Seabed, bed of a body of water to prevent the craft from drifting due to Leeway, wind or Ocean current, current. The word derives from Latin ''ancora'' ...

anchor
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 rock (geology), rock and 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 ...

sand
, or
silt Silt is granular material A granular material is a conglomeration of discrete solid, macroscopic scale, macroscopic particles characterized by a loss of energy whenever the particles interact (the most common example would be friction when gra ...
. 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 connect a Watercraft, vessel to the Seabed, bed of a body of water to prevent the craft from drifting due to Leeway, wind or Ocean current, current. The word derives from Latin ''ancora'' ...

anchor
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 ...

pier
s and
quays A wharf, quay (, also ), or staith(e) 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 Berth (moorings), berths (Moorin ...
. 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 used in or a . A hawser passes through a , also known as a cat hole, located on the ., third edition, Company, pp. 829–30, References External links * {{Authority control Nautical te ...
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 A wharf, quay (, also ), or staith(e) is a structure on the shore of a harbour or on the bank of a river or canal where ships may dock to ...

bollard
, 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
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nylon
. Nylon is easy to work with and lasts for years, but it is highly elastic. 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 A thermoplastic, or thermosoft plastic, is a plastic polymer A polymer (; Greek ''wikt:poly-, poly-'', "many" + ''wikt:-mer, -mer'', "part") is a Chemi ...
and
Kevlar Kevlar (para-aramid) is a heat-resistant and strong synthetic fiber Synthetic fiber or synthetic fibre (in British English British English (BrE) is the standard dialect A standard language (also standard variety, standard dialect, ...
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 A wire is a single usually cylindrical, flexible strand or rod of metal. Wires are used to bear mechanical loads or electricity Electricity is the set o ...
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 A wharf, quay (, also ), or staith(e) is a structure on the shore of a harbour A harbor (American English) or harbour (British English; American ...
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 Founded in 1970 the 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 i ...
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 Image:Suction cup pressure from collisions.svg, 232px, alt=A figure showing that the pressure exerted outside the suction cup exceeds the pressure inside. This pressure difference holds the suction cup in contact with the surface., The pressure on ...

suction cup
s or
magnet A magnet is a material or object that produces a magnetic field A magnetic field is a vector field In vector calculus and physics, a vector field is an assignment of a vector to each point in a subset of space. For instance, a ve ...

magnet
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 mooring / 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 File:Roue primitive.png, An early wheel made of a solid piece of wood A wheel is a circular component that is intended to rotate on an axle An axle or axletree is a central shaft for a rotating wheel or gear. On ...

pulley
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 The Industrial Revolution was the tra ...
(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 may refer to: *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 Arts, entertainment, and media *Lock (film), ''Lock'' (film), a ...
. 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 A road is a wide way leading from one place to another, typically one with a specially prepared surface which vehicles and bikes can use. Roads consist of one or two roadway A carriageway (British English ...
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

; *
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Sisal
*
Hemp Hemp, or industrial hemp, is a botanical class of ''Cannabis sativa ''Cannabis sativa'' is an annual herbaceous flowering plant The flowering plants, also known as Angiospermae (), or Magnoliophyta (), are the most diverse group of Embry ...
* Steel wire *
Polyethylene Polyethylene or (incorrectly) polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most common plastic in use today. It is a polymer, primarily used for packaging (plastic bags, plastic films, geomembranes and container ...

Polyethylene
*
Polypropylene Polypropylene (PP), also known as polypropene, is a thermoplastic A thermoplastic, or thermosoftening plastic, is a plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling. Most the ...

Polypropylene
*
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 natural ...
(e.g., used for deepsea mooring of offshore platforms) *
Nylon Nylon is a generic designation for a family of s composed of s ( linked by links).The polyamides may be or . Nylon is a -like , generally made from , that can be melt-processed into fibers, , or shapes. Nylon polymers can be mixed with a w ...

Nylon
*
Chain A chain is a wikt:series#Noun, 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 (physics), compression but line (g ...

Chain
;High-performance mooring lines * HMPE (floating) *
Aramid Aramid fibers are a class of heat-resistant and strong synthetic fiber Synthetic fiber or synthetic fibre (in British English British English (BrE) is the standard dialect A standard language (also standard variety, standard dialect, ...
(heat resistant) (including
Kevlar Kevlar (para-aramid) is a heat-resistant and strong synthetic fiber Synthetic fiber or synthetic fibre (in British English British English (BrE) is the standard dialect A standard language (also standard variety, standard dialect, ...
)


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