Synthetic Mooring: Helping to Conserve Marine Habitats

The Impact of Shipping on the Marine Environment

Globally, the shipping industry is relied upon for the import and export of goods across international territories. This trade allows for countries to sustain their economies by increasing the boundaries in which they operate. It also exposes consumers to new products and markets that aren’t available locally.

Shipping is heavily regulated by the International Maritime Organization (IMO) which is responsible for the safety of life at sea and the marine environment. The IMO has drafted guidelines relating to safe mooring practice for vessels that is due to take effect in 2024.

Moorings are a necessity for the safety of the shipping industry. They must be used to effectively secure commercial vessels, recreational craft, and marine Aids to Navigation (AtoN). Typically, the industry uses heavy-duty chain mooring affixed to an anchor or sinker that is positioned up to a few miles offshore.

The impact that moorings have and the environmental disturbance they create can be significant. Their use can impact water quality, the habitat for marine animals, and seagrasses that form part of the seabed.

Seagrass: Combating Carbon Emissions

Seagrasses are a vital part of the marine environment. In a blog by the CSIRO “Green superheroes of the sea” (2018), they discuss the positive impact seagrass has on the world’s oceans.

Seagrass is responsible for capturing carbon dioxide (CO2) from the water they live in and storing it, usually for more than 100 years. Interestingly, this is twice the amount of carbon that a tropical forest can store. “The grasses of the sea hold the key to a low carbon future and are helping the planet tackle climate change,” the CSIRO said.

In addition to this important discovery, seagrass provides food, habitat, and a home for marine animals and marine organisms. Marine animals use seagrass not only for sustenance but as a sanctuary. The underwater habitat keeps them safe from larger ocean predators.

A Habitat for Sea Creatures and Organisms

The seagrass protects these creatures from being swept away in stronger currents.

Seagrass and its dense, wide root systems are also vital to maintaining the stability of our sea beds. Their presence helps to reduce the movement of sand across the sea bottom, particularly where strong currents exist, during heavy storms or strong wave activity. This is important because sand movement is related to accelerated erosion that affects coastline communities.

Finally, seagrass filters pollutants out of the water and traps fine particles and sediment. This helps to improve water clarity. Bearing all this in mind, considering synthetic mooring as an alternative solution is a great way to help our marine environment.

The Impact of Traditional Chain Mooring

The impact of chain mooring on marine environments is two-fold. The first is the instance of drag and its implications on the sea bed. When the chain is used as a mooring line, it is connected to the sinker. For some distance due to its sheer weight and allowance for drag, it lies on the sea bed.

An allowance for thrashing is made during installation to allow for tidal conditions. This is to take into consideration the rise and fall of the chain associated with current and wave activity at that particular site.

The University of Wollongong (UOW) has been working on a long-term research project into the effects of anchor and chain scour across seafloor environments. The project is called “Dragging the Chain” and investigates the impact of ship anchoring and the use of mooring chains. In particular its impact on the seafloor and the marine ecosystems that call it their home.

In an interview with ABC Radio, UOW Researcher, Allison Broad explains the impact of drag and the scour it leaves behind. “As the chain moves on the seafloor, the damage can be significant with the potential to change ecosystems and reduce the biodiversity in that area,” Ms. Broad said. “Seagrass is the habitat and the nursery area for marine life. Depending on the species, it can take a very long time to regenerate,” Ms. Broad added.

The second impact the mooring chain has on marine environments is corrosion. The marine industry normally uses galvanized steel as it is protected by a zinc layer. This layer is better equipped to inhibit rust from occurring. However, over time the zinc coating degrades leaving the metal exposed to the elements.

The process of wear – and therefore corrosion – occurs more rapidly in high-salinity environments. This is particularly evident with the mooring chain where the natural current causes the chain links to rub against each other. This causes another problem, as the excessive wear requires ongoing monitoring and maintenance.

Failure to do so increases the risk of the mooring breaking and the buoy coming adrift. This poses a further safety issue for mariners relying upon the positioning of the buoy for navigation.

For marine animals and ecosystems, high levels of heavy metals present in the seawater can impact their health. Commercial fisheries need to consider the quality of the seafood they source with chain mooring likely to be contributing to the issue.

The research from the UOW indicates that marine-friendly mooring options are a good alternative. From a marine industry perspective, this is also known to be the case.

The Shift to Synthetic Mooring

Eight years later, the industry is beginning to discover the benefits of using synthetic mooring. Many customers prefer to use it over a chain or use it in combination for their installations.

While the initial commercial investment for synthetic mooring may be higher, the flow on benefits to the customer in terms of longevity, reduced maintenance, and being more environmentally responsible, is significant.

They save money due to the:

• A reduction in service replacement.
• Being able to commission smaller vessels
  due to the reduced weight of the mooring.
• Reduced OH&S risk for service personnel
  installing and maintaining the product.
• The product is quicker and easier to
  handle.

It is pleasing to note the growing popularity of this type of mooring solution.

Minimal Maintenance

Sealite’s synthetic mooring requires minimal maintenance. The mooring offers long-term longevity, reduced maintenance, and is more environmentally responsible.

Sealite distributor North West Marine reports an expected life in excess of 5 years – a vast contrast to chain in the same application that needs replacement every 18 months.

Synthetic mooring is a more economical choice for many reasons. Read the case study to find out more.

Our Online Mooring Calculator

To assist customers, Sealite has developed an easy-to-use, online mooring calculator.

This software takes into consideration the buoy model, water depth, mooring size, watch circle, wind speed, current, simulated mooring length and sinker mass. It then simulates the calculation, allowing users to visualise the effect of their selections on their installation.

Sealite Synthetic Mooring has also now been accepted for use by governments, ports, harbours, consultants, and Aids to Navigation service providers throughout the world. They offer advice on mooring solutions in line with IALA recommendations. Over fifty different types and sizes of synthetic mooring are available.

To learn about how synthetic mooring is being used in the UAE, read the case study on our website.