Pacific Maritime Magazine - Marine Business for the Operations Sector

Anti-Snapback Rope Fuses Can Prevent Mooring Line Accidents


November 1, 2018

A mooring line will stretch before it breaks, putting workers onshore and on deck at risk of a snapback. File photo.

The United States Coast Guard is still investigating a mooring line accident at the Port of Longview this past June that took the lives of two people. News stations in Washington State have reported that a line snapped as workers attempted to winch a vessel along the dock.

Kevin Kohlmann, security director at the Maritime Administration (MARAD), said the two victims – the chief mate on the ship and a dockworker – were likely standing in the wrong place during the winching operation. However, he went on to explain that knowing where to stand isn't always evident, especially during a winching operation.

When it comes to mooring line safety, "something that could help in the future are technologies like anti-snapback," Kohlmann said.

A New Safety Solution

Although the International Longshore and Warehouse Union (ILWU) Local 21, which represents dockworkers in Longview, Washington, could not be reached for comment, Kohlmann noted that union leaders have looked into anti-snapback technology following the incident.

But anti-snapback remains relatively unknown, despite its ability to prevent mooring line accidents in the maritime industry. A company called MoorGuard, based in Medina, Ohio, wants to change that through its anti-snapback rope fuses.

"We make a fuse which is maybe a meter or two long, depending on your application, and we use that at the end of your line as it goes on the bollard," said Tom Fields, the company's owner and founder. "The key to the MoorGuard fuse is these special fibers we made that stretch and don't come back. That's an important idea, because if it came back it would just be like a rubber band. We want it to stretch to get rid of that energy, to take the load on the line down to a safe level."

Fields said his product entered the market about three years ago. His early adopters include freight companies operating in South America and Australia, as well as port authorities that cater to the cruise industry.

"They've got areas where they have consumers walking by bollards that are loaded with these mooring lines of monster cruise ships, so they're working with the cruise companies to put the products in this unsecured area for consumer protection," Fields said.

Although cruise ships (as well as freighters) frequent ports in California, the Pacific Northwest and Alaska, Fields said his technology hasn't made its way to the west coast yet.

As his list of satisfied customers grows, that could change. Francis Pelosi of Canada Steamship Lines (CSL) said his company recently completed a six-month trial of MoorGuard's rope fuses. He noted his satisfaction, saying the rope fuses have "held to the strengths that we've required to keep our ships alongside" the dock.

Still, few maritime industry professionals have seen these rope fuses work, Pelosi said. Most people don't witness many mooring line accidents in general, he continued, since lines often break without anybody around to notice.

Tragic accidents like the one in Longview can help draw attention to safety concerns. But rope fuses such as those made by MoorGuard can also prevent equipment damage.

Fields mentioned that some clients have begun using his product for hurricane mooring purposes. Mooring lines often give way when tide levels rise, he noted, but rope fuses can absorb changes in water levels.

"If you put a big MoorGuard fuse out there, it'll simply stretch as the water comes up," Fields said.

How Anti-Snapback Fuses Work

The stress placed on mooring lines by tides, winching operations and simple use over time leads to corrosion. This results in dangerous situations, since it's hard to gauge how much strength an older mooring line may have.

"Lines do not maintain their strength over time, they get weak. They get weak at very, very fast rates because the polymer breaks down or the line gets damaged when loaded to high levels," Fields said. "A 100-ton line that's been used for two years and loaded often to 60 percent of its break strength might only have 50 percent of its original strength left."

To make matters worse, he added, companies routinely ignore recommendations from mooring line manufacturers designed to prevent the lines from becoming overloaded.

MoorGuard rope fuses serve as attachments that can prevent a catastrophic snapback. Fields describes a typical MoorGuard fuse as a small grommet, or sling, featuring a piece of rope sliced back into itself, creating an endless circle. Made with special, proprietary fibers, each fuse runs about a meter or two long.

"Our fuse looks like an endless piece of rope," Fields said. "You just stick it on the end of your mooring line, and our fuse replaces your eye at the critical length between the line and the bollard."

As both Fields and Pelosi described, if the mooring line holding the ship to the dock becomes overloaded or stressed, the rope fuse will simply stretch. Pelosi likened the fuses to silly putty.

"It's not going to snap back, the fuse is going to dissipate, it's going to elongate," Pelosi said. "Picture a line that just all of a sudden gets to a certain pressure, and it just exchanges its capacity."

Fields got the idea for his product not by observing the maritime industry, but rather through his knowledge of electrical systems. Mooring lines, he said, don't have the sacrificial component that other systems, like circuits, have.

Electrical circuits contain fuses that absorb and dissipate fluctuations in the average flow of an electrical current, preventing damage to household appliances like TVs and stereos. There's no reason, according to Fields, that rope systems can't operate in a similar fashion.

He pointed out that mooring lines, just like circuits, have to absorb changes caused by environmental factors, while at the same time holding the ship safely to the dock. Although many line manufacturers make mooring lines with high degrees of stretch, this often isn't enough to prevent accidents, especially when considering how quickly lines corrode.

"The one thing that's missing in the systems that we're using today is the concept of a fuse. Something that releases at a very specific known point that is below or around the same working load of the rope so you don't overload the rope and therefore put it in a situation where it's subject to potential failure," Fields said.

Combating Fear of the Unknown

According to Fields, many of his clients in South America own bulk carriers that handle raw materials like coal and gravel, which tend to erode the binding in mooring lines over time. Loading and unloading these materials, he pointed out, also produces a lot of boat movement at the dock, which means extra strain on lines.

Ports in the Pacific Northwest handle many different raw materials, such as soda ash, petroleum coke and talc. Longview itself has eight marine terminals, half of which are devoted to bulk cargo handling.

But most ports aren't yet ready to adopt a technology they know little about. Speaking about anti-snapback in general, Kohlmann noted that cost is an upfront factor that ports and shipping companies must consider.

Fields believes the benefits over time outweigh these costs, however. MoorGuard fuses, he said, start at around $400 and increase in price depending on size. For most vessels, equipping all 12 mooring lines with fuses adds up to roughly the cost of one mooring line.

"Safety has always cost money, and the upfront investment was something that always stopped people," Fields said. Using rope fuses is "a very, very inexpensive way of solving the problem."

MoorGuard's OpenWater design, in use at a MARAD facility in Beaumont, Texas. Photo courtesy of MoorGuard.

In an effort to improve its product, MoorGuard is currently working with clients to determine what size fuse to put on mooring lines, which can have different breaking strengths. But Pelosi said that even if the fuse isn't the correct size, it will still prevent the line from snapping back.

"The line's going to part, but as soon as you get to whatever the tolerance of the fuse is, it will start to absorb energy," Pelosi said. "You'll never reach the point where the fuse itself will part."

Following his company's trial of the product, Pelosi doesn't have significant concerns about cost, either. For a shipping company like CSL, he said, it amounts to "peanuts," especially when compared with the cost of replacing a mooring line.

"These fuses are so inexpensive," he said. "I love the product, it's the greatest thing ever made."


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