DOSSIER

 

Rethinking STS transfer safety


Whether reducing vessel weight prior to docking, exchanging guardianship of offshore cargo, or embarking on bunker operations, ship-to-ship (STS) transfer is a cornerstone of many shipping operations.*


STS transfers are increasing throughout the industry, particularly in regions, such as the Middle East. This has given rise to many new operators and companies specialising in this field, which has put pressure on multiple parties – operators, owners and crew – to ensure that this process is conducted safely and efficiently.

Examining existing STS legislation, a Master Mariner and partner at Clyde & Co explained the potential difficulties inherent in common riders that augment the requirement that STS transfers adhere to the latest ICS/OCIMF Transfer Guidelines.

He cited the example of wording that states; “Charterers shall provide, at their expense, all necessary equipment and facilities including fenders, hoses, mooring masters, etc for safe operations to owners/Master’s satisfaction, which shall not be unreasonably withheld.”

However, this opens the door for potential issues, such as - if the Master is not satisfied, is he really going to interrupt commercial operations to say ‘I want better hoses,’ ‘the fenders aren’t very good’ and ‘that supply vessel is not good enough’?

It demonstrates the need for the parties involved to carefully examine all aspects of STS transfer. In particular, it illustrates the need for suppliers to ensure that they are playing a role in raising standards by contributing their expertise, as much as their products.

In any oil transfer, equipment not only needs to improve efficiency while operating safely and function in a way that is easy to operate, but must also exhibit resilience in the face of environmental challenges.

In the case of oil transfer floating hoses, they are often at the front line of operations. A hose’s endurance will be tested by wave height and frequency, wind direction and shear, not to mention current strength, with these stresses impacting the longevity of equipment.

When it comes to hoses used in STS transfers, operability is a major factor, with past conferences on the subject lamenting lost time, due to crew being unable to install and connect hoses. It is therefore vital that suppliers examine the standards used, and whether alternative equipment may deliver better results.

Typically, EN 1765 is used to qualify STS hoses. However, the GMPHOM 2009 standard mandates tougher requirements, increasing resilience and service life beyond what is typical. This higher level of assessment guarantees a superior level of certainty and confidence when it comes to STS transfers, in line with best practice regulations, with more accurate performance predictors including service life and resistance.

CAPEX investment in this higher specification will ensure an increase in operations, a decrease in maintenance, and ultimately fewer expensive replacements over a project’s life-span.


Unique hose range

With over 40 years experience in transfer solutions for the shipping industry, Trelleborg Oil and Marine has used this standard when developing a unique solution for STS transfers - the KLELINE STS.

Due to the nature of their use, STS hoses can be subject to accidental kinks or crushes as a result of external forces – which in this case necessitates the use of a dual-carcass design, using technology initially designed for truck tyres. It is applied in the form of two carcasses made up of steel cables.

The first carcass provides resistance to internal pressure, up to five time that of the working rated pressure (WRP), with the second carcass responsible for generating resistance to STS inherent stresses and loads.

Unique to Trelleborg, a so-called ‘nippleless’ design proves its worth when it comes to the KLELINE STS. A perfect sealing solution is achieved with a continuous inner liner and integrated gasket – unlike the standard nipple hose, there are no stiff metal connectors in between sections, which means that the hose is more flexible, both increasing its operational lifespan, and increasing performance potential.

At the same time, installation is simplified, as this design does not require a gasket for each connection, culminating in a more resilient hose when it comes to managing stresses and strains. A more flexible design also allows hoses to be built from fewer, longer segments, decreasing the number of connections needed and simplifying installation.

What is essential is that suppliers, operators, owners and crew can work together to ensure that the correct standards are being used to maximise safety and performance – making the decisions that ultimately dictate the success or viability of an offshore project.

 

*This article was written by Nicolas Landriere, Product Manager, Trelleborg Oil and Marine.

 

 

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