After participating in a nine-month pilot, Maersk has committed to retrofitting the mooring ropes of its entire fleet with Snap Back Arrestor technology
Maersk spends nearly US$2 million annually on replacing some 1,000 mooring ropes and will retrofit the new Timm Snap Back Arrestor (SBA) ropes over the next five years as their existing ropes reach their five-year lifespan.
The SBA is an elongating core which sits within 12-strand plaited, mixed polymer or HMPE ropes. The core has greater elongation capacity than the outer rope, so if the outer, load-bearing construction breaks, the SBA reduces the resulting snap-back forces. The rope slumps rather than whipping across the ship and dock at speeds that can reach almost 800 kilometres per hour.
The retrofit is a continuous process organised so that it does not disturb vessel operations, with the ropes being delivered by Wilhelmsen Ships Service. Timm Ropes was established in 1772 and acquired by Wilhelmsen in 2015. The SBA line was launched in May 2019 after nearly seven years of development including lab and sea testing in both straight line and angled configurations. It has gained type approval from DNV GL, and the ropes have been tested according to the latest, 4th Edition of the OCIMF Mooring Equipment Guidelines.
The new ropes have a Maersk blue stripe, making it easier for operators to spot any damage or twists in the rope that could affect breakage.
Most Maersk vessels will be fitted with the Timm Master 12 SBA, a 12-strand plaited mixed polymer rope that has the same material composition as the Timm Master 8 rope currently being used. A few classes of larger vessels will be fitted with Wilhelmsen’s Acera line of HMPE ropes that have SBA integrated. “Ropes made from HMPE material are the same strength as steel ropes of the same diameter, but the weight is only one seventh,” says Veronika Aspelund, Business Manager, Ropes, at Wilhelmsen. “HMPE ropes are easy to handle and last longer than conventional ropes. In addition, a number of ports or terminals specifically require vessels calling there to be equipped with HMPE ropes, due to safety.”
Vessel mooring remains one of the most dangerous tasks crew and port workers can undertake. Snap back accounts for 60 percent of mooring accidents, according to the UK P&I club, with one in seven of those accidents resulting in fatalities. Statistics from the European Harbour Masters’ Committee show that 95 percent of personal injury incidents are caused by ropes and wires; 60 percent occurring during mooring operations.
Aslak Ross, Maersk’s Head of Marine Standards, says: “This SBA rope technology embraces one of the fundamental elements of our Safety Differently approach by building in capacity to safeguard people.” He hopes the company is starting an industry-wide transformation, leading by example to protect seafarers and dockworkers ashore.
In an effort to bring accident numbers down, amendments to SOLAS regulation II-1/3-8 and new guidelines for safe mooring are expected to enter into force on 1 January 2024. All new ships will be required to comply with the revised regulations for safe-to-use mooring arrangements. Mooring equipment will be required to be arranged to minimise obstructed access and view of the mooring area, minimise manual handling of mooring lines under load and minimise the need for complex mooring line configurations. Existing ships will be required to comply with new inspection and maintenance regimes.
DNV GL is continuing to focus on human-centric design for mooring solutions. “Humans have been considered in the design of equipment and facilities, but the focus has not been human-centric,” says Yiyang Li, Ship Life Cycle Management Consultant, DNV GL, and lead consultant for DNV GL’s Safe Mooring Team. DNV GL is conducting expert interviews with the aim of identifying gaps between claimed and actual crew performance as the industry evolves with larger ships, new mooring systems and increased use of shore power. Speaking in DNV GL’s Maritime Impacts, he says these developments are influencing the risk picture, and there has been a time gap in the update of routines. The result is that mooring safety has depended largely on seamanship and operator experience.
“We are also working to influence design using knowledge of human behaviour,” Yiyang says. “We are performing critical task analysis with owners and operators, and we aim to share this approach with the design industry. The goal is to allow human factors to have more influence in the design process. Not enough attention has been paid to overall solutions. The goal now is to consider the entire process from a combined human, operational and technological perspective.”