Mooring

A mooring is any permanent structure to which a seaborne vessel

(such as a boat, ship, or amphibious aircraft) may be secured.
Examples include quays, wharfs, jetties, piers, anchor buoys, 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.[1]

Mooring Post, Eisenhower Pier,

Bangor, Northern Ireland

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 A passenger ship mooring onto a
harbour in Limone sul Garda, Italy.

A dockworker places a mooring

line on a bollard.

The term likely stems from the Dutch verb meren (to moor), used in
English since the end of the 15th century.

Permanent anchor
mooring

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 Mooring line of Polish ship
Fryderyk Chopin.

These moorings are used instead of temporary anchors because

they have considerably more holding power. They cause lesser
damage to the marine environment, and are convenient. Where
there is a row of moorings they are termed a tier.[2] 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

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 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 but rare elsewhere.

While many mooring buoys are privately owned, some are available
for public use. For example, on the Great Barrier Reef off the
Australian 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 anchoring.

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 Twenty foot diameter Pile cluster and Mooring dolphins with
sheet pile cell mooring another sheet pile cell solar panels and LED
structure and five mooring structure lights
steel pipe pile tripods

There are four basic types of permanent anchors used in moorings:

[3]

Dor-Mor pyramid-shaped anchors

used in mooring

Dead weights are the

simplest type of anchor. They
are generally made as a large
concrete block with a rode

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 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

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 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, or silt. 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

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 cost, limited success on rocky
or pebbly substrates, and the
long time it takes to reach full
holding capacity.[4]
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. Lateral pulls cause

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 the side edges or corners of
the pyramids to dig deeper
under the floor, making them
more stable.[5][6]
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

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 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 anchors 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

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 deployment, high holding-
power-to-weight ratio, and
availability of temporary-style
anchors.

Mooring to a shore
fixture

Crew of Hong Kong's Star Ferry

using a billhook to catch a hemp
mooring rope.

A vessel can be made fast to any variety of shore fixtures from

trees and rocks to specially constructed areas such as piers and
quays. The word pier is used in the following explanation in a
generic sense.

Mooring is often accomplished using thick ropes called mooring

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 lines or hawsers. 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, it is pulled tight. Large ships
generally tighten their mooring lines using heavy machinery called
mooring winches or capstans.

A sailor tosses a heaving line to

pass a mooring line to a handler
on shore.

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 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

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 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
and Kevlar 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 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.

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 A typical mooring scheme

Number Name Purpose

Keep forward part of the ship against

1 Head line
the dock

2 Forward breast line Keep close to pier

Forward or head
3 Prevent forward movement
spring[7]

4 Back or aft spring[7] Prevent backward movement

5 Aft breast line Keep close to pier

6 Stern line Prevent forwards movement

The two-headed mooring bitts 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
[reduces] the risk of back injuries from heavy lifting".[8] The Oil
Companies International Marine Forum recommend the use of such
hooks in oil and gas terminals.[9]

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 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 cups[10][11][12] or magnets.[13][14] It
can also be used between ships.[15]

Mediterranean mooring

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 USS Orion (AS-18) "Med moored"
with the stern tied to the pier and
two anchors forward, in
La Maddalena, Sardinia.

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

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 Mooring involves (1) the sinking of a heavy weight to which a block
(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 wooden mooring bollard

A mooring used to secure a narrowboat (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.[16]

Types of canal moorings:

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 Mooring pin (boat operator supplied) driven into the ground
between the edge of the canal and the towpath with a mooring-line
rope to the boat.[17]

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.[17]

Mooring ring (permanent) affixed between the edge of the canal

and the tow path, with (boat operator supplied) rope to the boat.[17]

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.[17]

Mooring line materials

Regular mooring lines

Sisal
Hemp
Steel wire
Polyethylene
Polypropylene
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 Polypropylene
Polyester (e.g., used for
deepsea mooring of offshore
platforms)
Nylon
Chain
High-performance mooring
lines

HMPE (floating)
Aramid (heat resistant)
(including Kevlar)

See also

Transport

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 portal

Anchor – Device used to

secure a vessel to the bed of a
body of water to prevent the
craft from drifting
Anchorage (shipping) –
Designated location at sea for
ships to drop anchor
Berth (moorings) – Designated
location in a port or harbour
used for mooring vesselss
Mooring mast – Structure
designed to allow for the
docking of an airship

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 Sailing – Propulsion of a
vehicle by wind power

References

1. Maloney, Elbert S.; Charles

Frederic Chapman (1996).
Chapman Piloting,
Seamanship & Small Boat
Handling (62 ed.). Hearst
Marine Books. ISBN 978-
0-688-14892-8.
2. "tier". Oxford English
Dictionary. Vol. XVIII
(2nd ed.). Oxford
University Press. 1989.
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 University Press. 1989.
p. 74.
3. "About Moorings" (http://w
ww.the-lake-life.com/about
-moorings/) . The Lake
Life.
4. Jamestown Distributors.
"Mooring Basics – How to
Install a Permanent
Mooring" (https://web.archi
ve.org/web/20200302025
808/https://www.jamestow
ndistributors.com/userport
al/document.do?docId=110
7&title=Mooring+Basics+-

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 +How+to+Install+a+Perma
nent+Mooring) . How Tos.
Archived from the original (
http://www.jamestowndistri
butors.com/userportal/doc
ument.do?docId=1107&title
=Mooring+Basics+-+How+
to+Install+a+Permanent+M
ooring) on 2020-03-02.
Retrieved 2012-08-07.
5. Leonard, Beth A. (January
2014). "Everyday
Moorings" (http://www.boa
tus.com/seaworthy/magazi
ne/2014/january/everyday-
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 ne/2014/january/everyday-
moorings.asp) . Seaworthy
(January 2014). BoatUS
Marine Insurance Program.
Retrieved 24 August 2014.
6. US 5640920 (https://worl
dwide.espacenet.com/text
doc?DB=EPODOC&IDX=U
S5640920) , issued 1997-
06-24
7. Admiralty Manual of
Seamanship Volume 1
B.R.67(I)
8. "Let's go! Six-figure
investment made in port's
berths" (https://web.archiv
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 berths" (https://web.archiv
e.org/web/201509240805
00/http://www.portsmouth.
co.uk/news/business/local-
business/let-s-go-six-figur
e-investment-made-in-port
-s-berths-1-5853755?WT.
mc_id=Outbrain_text&obre
f=obinsite) . City of
Portsmouth. Archived from
the original (http://www.por
tsmouth.co.uk/news/busine
ss/local-business/let-s-go-
six-figure-investment-mad
e-in-port-s-berths-1-5853

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 755?WT.mc_id=Outbrain_t
ext&obref=obinsite) on
2015-09-24. Retrieved
2014-02-08.
9. "Quick release mooring
hooks" (https://web.archiv
e.org/web/201509130433
55/http://www.strainstall.co
m/what-we-do/our-system
s/jetty-and-berth-manage
ment/quick-release-moorin
g-hooks) . James Fisher
and Sons plc. Archived
from the original (http://ww
w.strainstall.com/what-we-
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 do/our-systems/jetty-and-
berth-management/quick-r
elease-mooring-hooks/)
on 2015-09-13. Retrieved
2014-02-08.
10. "First inland vacuum-based
mooring system installed
on St. Lawrence Seaway
locks" (http://www.professi
onalmariner.com/Septembe
r-2015/First-inland-vacuu
m-based-mooring-system-i
nstalled-on-St-Lawrence-S
eaway-locks/) .
Professional Mariner.
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 Professional Mariner.
September 2015. Retrieved
11 March 2017.
11. Hands Free Mooring (http
s://www.youtube.com/watc
h?v=jYf_iHCP14Y) on
YouTube
12. Stensvold, Tore (30
October 2015). "Nå skal de
suge fast skipene til kaia" (h
ttp://www.tu.no/artikler/na-
skal-de-suge-fast-skipene-
til-kaia/275889) . Teknisk
Ukeblad. Retrieved 18 April
2016.

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 13. Himanen, Laura (June
2016). Alternative Mooring
Systems (https://www.thes
eus.fi/bitstream/handle/10
024/111541/Himanen_Laur
a.pdf?sequence=1) (PDF)
(Thesis). Finland:
Kymenlaakso University of
Applied Sciences.
14. Zhang Qiang; et al. (2015).
"Automatic Ship Lockage
Based on Magnetic
Mooring" (https://web.archi
ve.org/web/20170909052
746/http://www.techrev.or
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 746/http://www.techrev.or
g.uk/jma/4.2/jma.4.2.10.pd
f) (PDF). Journal of
Materials and Applications.
4 (2). Archived from the
original (http://www.techre
v.org.uk/jma/4.2/jma.4.2.1
0.pdf) (PDF) on 9
September 2017. Retrieved
2017-03-11.
15. Van Acht, J.J. (26 July
2016). Intelligent Ship to
Ship Mooring (http://resolv
er.tudelft.nl/uuid:ca7a247a
-6e48-4c37-a690-47607
bc0615d) (Thesis). Delft
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 bc0615d) (Thesis). Delft
University of Technology.
Retrieved 11 March 2017.
16. "The Boater's Handbook" (
https://canalrivertrust.org.u
k/media/library/141.pdf)
(PDF). Canal & River Trust.
Retrieved 13 May 2016.
17. "Banksides and Mooring" (
https://web.archive.org/we
b/20150402133648/htt
p://www.french-waterways.
com/practicalities/mooring.
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Archived from the original (
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Page 31 of 35
 http://www.french-waterwa
ys.com/practicalities/moori
ng.html) on 2015-04-02.

External links

IACS Unified Requirement A:

Mooring and Anchoring (http
s://web.archive.org/web/20081
030171636/http://www.iacs.or
g.uk/document/public/Publicat
ions/Unified_requirements/PD
F/UR_A_pdf148.PDF)
Find moorings (http://www.ulti
mateberths.com/)

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Page 32 of 35
 "Docking The World's Great
Liners" (https://books.google.c
om/books?id=nuMDAAAAMB
AJ&dq=popular+mechanics+1
930+aircraft&pg=PA786)
Popular Mechanics, May 1930,
article on docking large ships
in the first half of the 20th
century
ShipServ Pages Mooring
Ropes (http://www.shipserv.co
m/category/mooring-ropes/53
84)
Video on Canal Mooring (http

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Page 33 of 35
 s://www.youtube.com/watch?v
=AE0MEQb4y-Q)
Anchor Chain and Mooring
Fittings (https://aqualogistics.c
om.sg/aqua-logistics-pte-ltd/a
nchor-chain-and-mooring-fitti
ngs/)

Retrieved from
"https://en.wikipedia.org/w/index.php?
title=Mooring&oldid=1217363158"

This page was last edited on 5 April

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 2024, at 11:49 (UTC). •
Content is available under CC BY-SA
4.0 unless otherwise noted.

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