The four risks of temporary mobilisations

The text below was inspired by my many discussions with my ex colleagues Mr. Richard William Taylor, Senior Principal Surveyor for DNV Aberdeen. 

Richard was the first to synthetize the four risks of temporary mobilisation of equipment based on his vast experience as field surveyor in North Sea.

Thank you very much Richard for sharing with me your deep insights on this matter! 


This text represents only the author personal opinion about the engineering topics presented. This personal opinion is not comprehensive and definitive and it is rather an invitation for discussions, comments and feedback and shall be considered accordingly.

The author can’ take any responsibility for any type of use of this text.  


No anecdote this time – just experience



My colleague, Mr. Taylor, was asked to support the owners of offshore vessels to identify the class and statutory scopes to be addressed for the preparation of the offshore campaigns. 

I remember having long discussions with Richard, searching for the “holy grail”: a comprehensive algorithm to guide everybody through the complexity (one may read jungle) of this jobs as well through the complexity of maritime rules and regulations.

As during any “holy grail” hunt, we never achieved the final target, the comprehensive algorithm, but at a certain point Richard found what I think is the most synthetic way to define the risks associated with the temporary installation of equipment for offshore services.

These risks are definitively not the so much needed algorithm but, in my opinion, are the right starting point for identifying the class and statutory scopes to be addressed for the preparation of the offshore campaigns. 

Richard found that there are four groups of risks to be addressed.

Two risks are the “structural” risks:

· 1st Structural: Holding to the deck - commonly called seafastening;

· 2nd Structural: Ship's structural strength -local and general – and ship‘s stability (intact and damaged).

Other two risks are “non structural” risks:

· 3rd Non Structural: The risks associated with the equipment;

· 4th Non Structural: The risk generated by the integration of the temporary equipment into ship's layouts and systems.

The structural risks


The 1st Structural Risk Group – Seafastening

The temporary equipment in the deck spread has to stay safe on board on the allocated positions during transit/survival and operations. 

In general, it is expected that the project will provide the seafastening solution because the equipment are the responsibility of the project team. However, the project team has to collaborate closely with the ship’s team because the ship‘s team knows better the details of ship’s structure. 

Usually, the verification of seafastening solution is provided by marine warranty companies.

If the loss of seafastening could generate pollution or could damages the vessel, the final responsibly will stay with the owner or ISM/DOC holder and will be verified by class as well.

The 2nd Structural Risk Group - Ship's structural strength -local and general – and ship‘s stability (intact and damaged)

The strength and stability of the ship shall be sufficient at any time during transit/survival and operations. The responsibility for dealing with this risk stays only with the owner or ISM/DOC holder. 

These aspects are part of the class and statutory scope however the offshore project stakeholders may request the verification of these aspects by the marine warranty provider as well.

Non-Structural risks

3rd Non Structural: The risks associated with the equipment

The equipment can generate various non-structural risks associated with aspects as fire safety, pollution, dangerous goods, hazardous and noxious liquids.

For example a DG unit may have hot surfaces, leaking fuel pipes/hoses or generate more than 375 kW (500 HP) therefore fix firefighting system is requested. 

Some risks are less obvious. An anecdote tells that a professional found out that a general alarm trial was triggered on deck how time he worked in a container on deck. Unfortunately he heard nothing so he was very concerned about this situation because everybody likes having the chance to act as quick as possible in case of fire or if ship sinks. The container has to be wired properly to the ship’s alarm system. 

4th Non Structural: The risk generated by the integration of the temporary equipment into ship's layouts and systems

The integration of temporary equipment on board may change significantly the layout of vessel generating new risks. The vessel is practically altered and sometime converted in order to accommodate the mission equipment and to fulfil the tasks of the project.  

For example: a DG unit may exhaust hot gases in a hazardous area, a manned space requests escape routes, emergency lighting, green/black piping or installation of additional lifesaving appliances.

An anecdote tells that during a regular trial done when the vessel was already on sea on way to the job, it was found that a temporary container installed on deck obstructed an emergency exit or simple the access for maintenance of an important system. Usually this anecdote raises some smiles on many faces.

The association of the Non Structural Risk Groups with the Project or with the Ship is less clear. 

In general, it is supposed that the Project team knows better the equipment therefore it is expected that the Project Team will make the initial risk assessment of the equipment to be mobilized on board and will identify, eliminate or mitigate any risk brought by equipment on board. 

The Project team shall inform Ship team about all risks brought by equipment on board.

Both teams shall collaborate for identifying, eliminate or mitigate all the risk resulted from the integration of temporary equipment on board.




Thinking risk is the right way to start an offshore operation.

The overall risk analysis of offshore operation must include the analysis of the risks associated with the mobilisation of temporary of equipment on board of offshore service vessel and the “four risks” logic briefly presented above provides the starting point for this analysis.