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6 Different Types of Boat Moorings

White moorings attached on a wooden floor.

I have worked as a professional writer for the last ten years, but before then I served for six years as a naval officer. Life at sea is difficult, dangerous, and challenging. All mariners, no matter the type of vessel that operate or service they work in, live a life that is different from that experienced by most people.

Even with advancements in hull structures, propulsion, navigation, and crew comfort, once we are underway, we are in a constant struggle against the elements.

Things get no safer or easier when pulling into port or anchoring offshore. In fact, these operations are some of the hardest and most dangerous that any ship driver contends with. It takes real skill to attach a large ship to a mooring. To do so, a mariner must know the kind of mooring they will tie their vessel to.

As a writer, part of my job is to make complex subjects easy for non-specialists to understand. In this article, I summarize what anyone would want to know about moorings.

What is a Mooring?

A mooring is any permanent structure to which a vessel can be secured. The word “mooring” is both a noun and a verb. The noun is the structure. The verb mooring refers to the act of lassoing, tethering, tying, or otherwise securing a boat to a fixed object.

Vessels can be moored to buoys, quays, wharfs, jetties, and piers. Mooring a vessel can be done in a few different ways. While it takes trial and error to perfect this skill, newly minted mariners should never attempt to do it alone.

In navies around the world, the entire process of mooring is managed, tightly supervised, and sometimes carried out entirely, by the captain of the vessel. In most instances, the captains of large vessels never let junior people moor the ship without close supervision. It takes years of experience and apprenticeship before any mariner is ready to carry out this operation on their own.

Types of Moorings

Most boat moorings are stationary platforms. They are found on wharfs and piers around the world. Here are some of the types of mooring and their essential features.

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1. Timber staging

Thick rope stitched on a red steel beside the sea.

This type of mooring consists of piling and decking. Some of the prominent features and advantages of this type of mooring include:

– It allows wildlife such as water voles to access the bank and, provided there are spaces left in the decking for light to penetrate, bankside vegetation will continue to grow.

– It is suitable for a river or broad where there is not a large tidal range.

The staging for this type of mooring should be kept as narrow as possible. The decking should be cleaned regularly, and the pilings should be replaced every ten years.

2. Quay heading and piling

Different boats ligned up on the sea.

This type of mooring is suitable for most tidal ranges. However, its structure tends to be relatively complicated. It should vertical fenders and rubbing strips in areas where the tides swell exceptionally high.

Many of these types of mooring structures use steel. But plastic and timber are also used. There should be good drainage systems behind pilings to stop the formation of puddles during high tide.

3. Pontoons

The boat being anchored in the seashore.

Pontoons can be used as a mooring structure. There is great advantage in using them. Though they must be secured by an anchor or piling, they can be installed relatively quickly.

Pontoon moorings must be cleaned regularly. They are suitable for wider navigation areas with a mid-to-high tide range. You will not find them in narrow channels, as they can impede navigation.

Related: Different Types of Pontoon Boats

4. Swing or trot

A distant view of boats overseeing the hillside and trees.

This is a single buoy permanently fixed to the bed by a cable to provide stable mooring. A row of linked buoys is a trot mooring. It enables vessels to secure themselves in a way that prevents them from drifting with the wind or current.

Maintenance is generally low on this type of mooring. It has a low impact on wildlife and does not affect the landscape too much. The chains on these moorings must be regularly inspected and replaced.

It is not suitable for rivers, but it is perfect for broad areas with exceptionally strong currents.

5. Dolphin

A mushroom-shaped still stitched with a thick rope in the seaside.

This type of mooring consists of a number of vertical piles driven into the river or broad bed. These are connected with horizontal beams to which a vessel can moor. The timber piling on this type of mooring is bulky.

It has a life span of 20 years. It is most suitable for rivers and broads with a variety of tidal ranges.

6. King post

A dark rope stitched on a samson post with boats on the background.

This is the most common type of mooring structure in the world. It is certainly the one that I most encountered when I was in the service.

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It consists of either a single piled post or two posts that allow fore and aft mooring. If there is one post, then the boat must move with the wind and current to tie up. Indeed, securing a ship to a single king post can be tricky.

I have done on a small craft (under supervision) on which it is much easier to feel the motion and general drift. You must have absolute mastery of your helm and engines to secure the vessel safely to this mooring structure.

This type of mooring structure is most suitable for broad areas in which there are not strong currents.

Important Points to Remember During Mooring Operations

Two man mooring the boat.

Securing a water craft to a mooring structure is always a difficult and dangerous task. No matter the size of the craft you are operating, you must have adequate training and preparation before doing it. Indeed, every sailor has heard horror stories of how people have been injured, crippled, and even killed during mooring operations.

The snapping of lines is one of the greatest threats to life and limb during this type of operation. The larger the vessel the more force will be put on the lines that are used to secure it to the mooring structure. The deck crew must consist of experience people who know how to give and take in slack while securing the ship to the moor.

Although smaller vessels do not have such deck crews, it is important for the few people who are responsible for tying the boat to the mooring to pay attention to what they are doing. Even smaller lines can snap and cause injury.

In any case, here are a few simple rules to enforce during mooring operations:

1. Do not allow any extra crew member on deck

Two crew members wearing orange suits facing a ship.

Ensure that no extra personnel are present at the mooring station except those who are involved in the operation. Anyone who is not assisting in the mooring operation must be asked to leave the mooring station for his/her and other’s safety.

2. Know the weather conditions

Before planning the mooring operation, consider the weather condition by taking factors such as wind and current. The ship’s master and responsible officer must have the details of current and future weather data before commencing the mooring operation.

3. Check all mooring equipment

Thick white ropes on the boat with crews on the background.

Check all the equipment (mooring winch, drums, windlass etc.) involved in the mooring operation for any kind of problem. Proper routine maintenance is the key to ensure smooth running of mooring equipment and systems. You should also check the load sensors of the mooring winches.

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4. Check the tail of the mooring line

If the mooring wire line is provided with tail (short lengths of synthetic fiber rope which are placed in series with the vessel’s winch-mounted wires to decrease mooring line stiffness and thus to reduce peak line loads and fatigue due to vessel motions) ensure same size and material of tails are used for all lines in the same service (breast, spring and head lines). Different tail size and material would lead to uneven load in the mooring line.

5. Tend one line at a time

This is not possible if you are on a large vessel. But it is possible if you operate a smaller craft. In these situations, you should tend one line at a time when mooring. If this is not done, it may increase the load in the other tended lines. If two lines are tended together it may lead to overloading and breakage.

6. Keep a check on the mooring line load

Two crews mooring the boat beside the port.

Ensure that the allowable breaking load in any of the mooring lines does not increase 55% of its Maximum Breaking Load (MBL). This is to prevent the line from snapping.

7. Avoid mixed mooring

Mixed mooring is extremely dangerous. Generally, mooring lines of the same size and material should be used for all leads, if this is not possible due to the available equipment, all lines in the same service should be of the same size and material. The use of mixed moorings comprising full length synthetic ropes used in conjunction with wire should be avoided. 

If a synthetic rope and a wire are used in the same service the wire will carry almost the entire load while the synthetic rope carries practically none.

8. Keep a continuous check

Load on the mooring lines must be checked continuously even after the mooring operation is over. If there is any change in the ship’s ballast condition, the lines must be slacked or tightened accordingly. The condition of the rope material should also be checked to foresee unfortunate accidents.

9. Arrange mooring lines symmetrically

All mooring line must be arranged as symmetrical as possible with the breast line. The breast line should be perpendicular to the longitudinal centre line of the ship and the spring line should be parallel to the longitudinal centre line.