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Lessons Learned in Safe Mooring

Key take-aways:

  • Master and Pilot need to have a shared mental picture of the entire mooring operation.
  • Communication in a common language is essential to everyone participating in the operation (pilot, crew, tugboat, port, vts etc.). There are no stupid questions, make sure you ask if you are not certain.
  • The Master is always in overall charge of the vessel. If a pilot or pilots are employed, their role is an advisory, local expert one. Masters should exercise their overriding authority to ensure safe mooring and manoeuvring.
  • The mooring operation should always be well-planned, according to a systematic method, and communicated well before the actual operation. Any and/or sudden changes to plan(s) should be briefed with everybody participating in the operation.
  • Many factors contribute to the durability of mooring lines, and therefore it is vital that the rope manufacturer’s instructions are always followed, especially the factors that reduce the Safe Breaking Load (SBL).

Ship handling 


“The most dangerous people are the ones that believe they can handle their ship without listening to advice – they often make a near miss and then hand it over to a Pilot”
– Georg Haase, Captain, Pilot, CEO Nautitec Leer 


During the Master-Pilot exchange, a shared mental picture must be established regarding the operation plan and the distribution of tasks. The Master, the Chief Officer and the Pilot often coordinating the ship handling together. To ensure that this teamwork is both safe and effective, both the Pilot and the Crew must actively include each other in the team. Clear communication is a critical part of safe operations, and it needs to be clear who is going manoeuvre the vessel – there can only be one person at the controls.

“It must be clear who is actually handling the vessel.”
– Mikael Hilden, Captain and Maritime Consultant 


It can be tricky to establish a common operation language. In some countries and ports, it is claimed that since no legal English requirements are in place, and no IMO standards exist for tug commands, the pilot will communicate using the local language. To avoid the risks of miscommunication and to ensure that all critical communication is heard and understood by everybody participating the operation, it is considered best practice to use the English language. The Master always has ultimate responsibility for the operation, even when the vessel manoeuvring is delegated to the Pilot. In many jurisdictions, pilots can limit their liability substantially, and therefore vessel crews should plan the voyage/passage and manoeuvring if no pilot is employed. It should be kept in mind that the Master’s overriding authority cannot be overemphasised.

To ensure that ship handling skills are continuously developed and maintained, all deck officers should receive training and coaching regularly.


Tug operation 


When used correctly and with good coordination, tugboats enable mooring operations when a vessel’s own propulsion capabilities are not sufficient in the prevailing conditions. However, it should be kept in mind that utilising tugs also complicates the operation, since apart manoeuvring own vessel, the tug(s) need to be coordinated and communicated with.

Tugboats come with several different propulsion arrangements that inherently affect the capabilities and suitability of different types of vessel assistance and mooring operations. Bollard pull capacity is not the only parameter vessel command should look at when making safe mooring plans. It is important that vessel command is also well updated on different tug propulsion systems and their capabilities and limitations. This knowledge, combined with attending pilots’ inputs, will increase safety, and avoid miscommunication and troublesome surprises.

Before commencing a tug operation, a common plan needs to be agreed upon. Following a clear plan makes it easier to detect possible deviations from the plan. Many accidents have started with several small deviations from the plan which then led up to a major deviation that ultimately caused the accident. To avoid human errors, it is essential that the plan is monitored by the crew and by the pilot and that closed loop communication is used throughout the operation.


“I see a lot of Captains just standing next to you in the manoeuvres, and they don’t ask any questions. Maybe they are clear on what’s going on, but sometimes I really get the feeling that a lot of them are not clear. They just give it over in the hands of the Pilot. So, my suggestion to all seagoing personnel would be – don’t be afraid to ask. There are no stupid questions. It is only stupid not to ask.”
– Dirk Friedsam, Vice Chairman, Harbour Pilots Bremerhaven 


The most essential part of the tug operation is preparation and communication. From a tug point of view, being the smallest vessel towing and assisting a much larger vessel, often in very confined space, is a dynamic risky situation, where the person manoeuvring the vessel must often react very quickly to unexpected changes. There is also a lot of time pressure that could lead to miscommunication and hurried decisions. Masters are encouraged to request, well in advance, a comprehensive manoeuvring and mooring plan from the port and from the possible attending pilots.


New Technology 


Monitoring of mooring lines has not been regulated before, but that is about to change. Safe mooring is a part of a new SOLAS regulation, which will be introduced in 2024, where, among other things, the monitoring of safe technical lifetime for mooring line is specified.

Many factors impact the forces the mooring lines are subjected to. There is currently no uniform way of measuring the actual forces any one line has been subjected to. To give some examples; Safe Working Load (SWL) should always be 50−60 % of the Maximum Breaking Load (MBL) – how do you measure this in practise? Another question is, how much is known about the SWL of the bollard on shore? Incidents have happened because of inadequate anchoring of the shore bollard.


“That is one thing we are looking at now – how we can calculate the mooring lines technical age. It has nothing to do with how long the line have been on the drum, it has to do with how many times we have used the line with a high tension.”
– Anders Nylander, Captain, Marine Superintendent, Wallenius Marine. 


To improve safe mooring, there should be a method to calculate how many times a mooring line has been subjected to high tension. Another important element is to establish company and vessel specific methodology and guidelines for the crew regarding the use of a sufficient number of mooring lines and their correct arrangement for the actual and forecasted meteorological conditions. The type and quality of mooring lines varies. For a human eye, a mooring line can appear to be in good condition, although there may be invisible structural weaknesses that can go unnoticed. A snap-back accident can cause severe injuries or even death. It is therefore recommended that mooring lines should only be stretched to the maximum MBL three times.

In tugboats’ towing lines, it is standard to count the age of the line in relation to the amount of usage and the amount of tension.


Additional Information 


List of amendments expected to enter into force this year and in the coming years ( 

IMO adopts new requirements focusing on the safety while mooring ( 

This statutory news summarises IMO’s main recommendations. ( 


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