A new world emerging for STS

Breakouts do occur in STS transfers, with events leading to the breakout often occurring some time before the vessels come apart.

“In many cases, the first mooring rope failure occurs at least 30 minutes, if not longer, before the actual physical breakout,” said Capt. Gilchrist. “With minimal crew on the tankers generally, the focus of the crew is on rectifying the mooring situation, especially if a deterioration in the weather or sea-state is the cause of the mooring failure.”

In that time the hoses need to be disconnected manually, a process that can easily take more than 30 minutes. The process involves removing nuts and bolts, blanking the hoses and passing the hoses across with the crane. The procedure requires a number of people at the manifold who are potentially in the line-of-fire as the ships move apart.

It was these elements that SafeSTS sought to address with PTX. “From an environmental perspective, there can be good reasons for having to depart in a hurry; for example, from the weather closing quickly and wanting to depart quickly before the mooring ropes start to part,” said Capt. Gilchrist.

SafeSTS approached Gall Thomson, a company that is a leading provider of breakaway couplings in the offshore sector and the LNG sector. In the LNG sector there is a requirement to have active breakaway couplings; that is a breakaway coupling that is operated intentionally by the user, rather than passive activation without intervention.

Capt. Gilchrist refers to the company’s approach to safety as a ‘Vision Zero philosophy’.

“Vision Zero was an initiative taken up by the Swedish government to reduce fatalities on the roads. And it was very successful, in that, it does not just look at a single element, but it looks at the system as a whole – the construction of the car, the rules, the road, monitoring systems. Every element of it is looked at holistically,” he said.

Applying that philosophy to STS, barriers to failure may involve management processes, or the Mooring Master’s experience. People make mistakes, it is human nature. “Would it not make sense to have another barrier in place?” asked Capt. Gilchrist. He cited an example whereby a Mooring Master was loading cargo and the weather deteriorated. The operation must stop and the vessels may have to depart quickly. “Having a PTX on the manifold would allow the POAC to make an immediate decision to stop the cargo, activate the PTX, pass the coupling back instantly to the other vessel, and then go to mooring stations for unmooring,” explained Capt. Gilchrist.

The avoids a potential 40-minute delay to stop cargo operations, disconnect and unmoor. During that time, an uncontrolled breakaway could occur. Given that 70% of STS incidents involve mooring, it is likely that a controllable breakaway coupling like PTX will be added to the STS guidelines and may be mandated by authorities for certain STS operations, especially those taking place in challenging offshore or environmentally sensitive areas.