Blog Summary:
- 80% of unexpected challenges and delays in marine projects is cable failure.
- Cable failure creates risks for losing expensive subsea equipment.
- Full-strength underwater cable terminations prevent cable failure during deployment and retrieval of subsea equipment.
- Unlike other helical terminations, PMI’s grips are built to hold your subsea cable to the full-rated breaking strength
- A benefit of the helical wire design permits easy installation of the termination anywhere along the length of the cable and does not require access to the cable end.
- Can be easy installation anywhere along the length of the cable and anywhere in the field.
- Do not require tools or cable preparation.
More subsea projects are happening than ever before, and ROVs, side-scan sonars, and other offshore equipment are almost always an element within them.
When equipment like ROVs and side-scan sonars are deployed or received, the twisting and bending of the cable at the termination point is common. Side-scan sonars and ROVs need these cables to stay intact and be able to bear the weight of the equipment. If these cables can’t keep up, it will cost serious delay and expense to projects.
Cable failure is the cause of 80% of unexpected challenges and delays.
The most common instance happens when subsea equipment is deployed from a vessel or retrieved from the sea and fails due to an extreme amount of tension being placed on the attached subsea cables. If these delicate cables are not terminated properly, they experience damage from strumming and snap loading. At this point, your crew can find themselves spending a good day starting over with installing a brand new termination – costing your project valuable time and money.
Without a proper underwater cable termination or grip, all of the stress and tension is concentrated along the cable where it is attached to the equipment. This is a ton of localized stress on what is usually a very expensive mechanical, electrical, or optical cable. Without a full-rated strength termination, you could be creating a recipe for disaster – cable damage, or worse, a cable break that results in the loss of expensive equipment.
How Helical Terminations Prevent Cable Damage
Helical terminations are designed to function similarly to a Chinese finger trap — a childhood toy that is a woven paper tube letting you place a finger into each end, and then, as you try to pull your fingers out, the tube tightens around your fingers. The harder you try to pull, the tighter the tube grasps your fingers, creating a secure hold.
Helical terminations work the same way. Helical rods are wrapped around the subsea cable at the termination location of the undersea equipment. With a helical termination, all of the stresses that would occur at one localized point on the cable are spread out over the length of the cable wrapped with the helical rods; therefore, greatly reducing the stress on any specific location of the cable.
To be technical, axial loading, a force that passes through the center of an object, causes elongation of the helix (or cable) and results in radial contraction. This compressive force gives the helical rods its ability to hold force. If you hold one end of the helical rod and attempt to pull the cable out, you transfer the load from the cable to the helical rods.
If at any point the load increases, the holding force increases. This mechanism provides a gradual transition of the load from the cable into the helical rod until the helical rods carry the full axial load.
Creating Reliable Attachment Points
A benefit of the helical wire design permits easy installation of the termination anywhere along the length of the cable and does not require access to the cable end. Many times attachment points are needed along the length of the cable. A good example of this is for creating an attachment point for the cable to be lifted from the seabed.
Why PMI’s Helical CABLE-GRIP™ and STOPPER-GRIP™ Terminations are a Preferred Choice
Unlike other helical terminations, PMI’s grips are built to hold your subsea cable to the full-rated breaking strength. When you are working with some of the most advanced and extremely expensive machinery in the industry, you can be confident that PMI’s equipment protects yours better than any cable hardware on the market today.
PMI’s Helical Terminations:
- Generate full-rated breaking strength.
- Permit easy installation anywhere along the length of the cable and anywhere in the field.
- Do not require tools or cable preparation.
- Come furnished in galvanized steel. Other materials, such as stainless steel, are available upon request.
- Work with many jacketed and synthetic strength members.
Invest in your project’s future
PMI’s Cable Grip and Stopper Grip Terminations are an inexpensive investment for preventing damaged cables or replacing a lost piece of expensive robotics. PMI underwater cable terminations have been used on cables for over 50 years, preventing subsea cable damage and maintaining cable integrity.
Check out our Full Rated Strength Terminations:
PMI offers Cable-Grip, Stopper-Grip, and EverGrip Terminations that all utilize Helical Rods.
Not sure what your project needs or have more questions about our helical terminations? Ask one of our experts today to help.
The Oceanology International conference covers such a wide range of industries, all with the common mission of measuring, developing, protecting, or operating in the world’s oceans, providing lots of room for potential collaborations and idea sharing among market leaders.
Being a conference with numerous offshore/subsea market leaders in attendance, it provides an opportunity for attendees to become inspired by new advancements within the industry and develop new customer relationships. Of particular interest to our team were new equipment and companies that acquire, transfer, and store data and analytics technologies.
We also noticed many oil spill company leaders were in attendance, which was interesting to see the continuing developing partnerships and collaborations between the marine technology companies and the oil and gas sector.
Through the bustling exhibit halls and between sessions, we had the opportunity to talk with multiple attendees about the economic status of some of these new markets. One thing most sector leaders agree on is that the market will eventually bounce back—but the one unanswered question is still a matter of when.
Much of the conference buzz also surrounded themes around autonomous unmanned vehicles (AUVs,) oil spill equipment, remote operated vehicles (ROVs), and various new software opportunities pertaining to data management.
The ever-growing capabilities of unmanned vehicles, along with industry applications, communications, and data are driving further advances in the ways that we collect information and work within the oceans.
With nearly 500 exhibitors from dozens of countries around the world, Oceanology International gives PMI a unique opportunity to meet with companies and discover their innovative solutions to today’s marine technology challenges. It also provides a great opportunity to share about our innovative subsea cable technologies and to create new partnerships and collaborations.
PMI is positioned well within this field given the application of various cable solutions such as our no tool or prep required cable strain relief systems (BSRs), synthetic cable terminations, and 3rd party cable testing capabilities which provide much needed services to the a wide range of markets who are associated with ocean work. Our custom cable subsea systems and deep subsea cable expertise explain why companies around the world count on PMI. When you’ve got a lot of ocean in front of you, you need PMI behind you.
See you back in London for Oceanology International 2020!
PMI certainly enjoyed the always educational environment at Subsea Expo 2018 in Aberdeen! It was a pleasure to meet with so many energetic and skilled specialists working within the industry.
The innovative solutions our industry develops continue to amaze and inspire us within the promising direction of the offshore energy market.
From the Awards Dinner, State of Sector/Industry Overview Keynote Session presented by Subsea UK Chief Executive Neil Gordon, to the breakout sessions, panel talks, and networking events, Subsea 2018 was surely an event not to be soon forgotten.
Breeding Ground for Innovation
The conference offers a unique environment attended by Subsea operators, supply chain engineers, CEOs, sales marketers, developers, IRM companies, cable suppliers, and more. The expo is a breeding ground for innovative solutions and partnerships to further evolve today’s subsea industry.
Through our many conversations with game-changers in the industry, a few common themes emerged that we wanted to share with you as our conference takeaways.
New Cable-free ROV Solutions
Much of the current market buzz seems to revolve around the possibilities surrounding AUV & ROVs. The implementation of remote subsea junction charging boxes for AUVs would eliminate the costly need for traditional subsea cables. Instead, the vehicle would plug into a charging station on the sea floor. This opens up a multitude of new opportunities surrounding sea floor connections, potential cost benefits, and the need for specialized remote subsea junction box cables.
Mentoring Future Leaders
In addition, reiterated throughout the event was a strong emphasis of the need to educate and train the next generation of subsea market leaders for an exciting, yet challenging industry.
This was also evident throughout the exhibit hall with opportunities for pupils to experience various facets of the subsea industry, from operating machinery with virtual reality, to Subsea UK and OPITO’s “Energise Your Future” campaign.
It was not uncommon to run into multiple local high school pupils attending the expo and looking to absorb all the knowledge and information they could.
While these young, future leaders may currently not hold the answers for commonly shared frustrations around market conditions, lead times, costs, and CAPEX restrictions, it was a friendly reminder that within years, a fresh pair of eyes may be able to revolutionize the markets we’ve all taken part in growing to the high level which it is at today.
Ice hasn’t necessarily put a chill on the development of offshore wind in the Great Lakes of North America, but it does pose a significant challenge — both in the design of offshore wind turbines and the maintenance of subsea power transmission cables.
Winter is a wildcard for the Great Lakes because the offshore wind industry has traditionally avoided ice-prone regions. Most new oceanic wind farms can tap decades of knowledge gleaned from the maturation of Northern Europe’s offshore wind industry.
That’s not exactly the case for projects in water that freezes every year. The first wind farm designed specifically to cope with ice opened off the west coast of Finland in the autumn of 2017. The 42-megawatt Tahkoluoto wind farm relies on gravity-based foundations that are tapered at water level to resist friction with ice.
Ice and subsea cables
Reports on the Finnish wind farm have mentioned the tower base design but haven’t delved into the implications for subsea cables. We’re not privy to the technical specifications of the project’s subsea cables, but we can offer a few insights based on our decades of experience with subsea cables in harsh environments:
- The extreme weight and mass of ice place relentless pressure on anything in its way. Wind farms on the Great Lakes have to be designed with these risks in mind, laying cables strategically to keep them away from ice flows and buildups. The inherently unpredictable nature of weather and the motion of ice could conceivably surprise wind farm developers.
- Winter repairs will be extremely complicated. It’s difficult enough to send a ship to the site of a cable break in the open sea — it can take weeks or months to get a crew to the site, fetch the cable, repair it, and return it to the seabed. Imagine attempting repairs in the winter in the Great Lakes where variable weather changes the ice thickness constantly.
Engineers can design for the most likely scenarios for subsea cables, but there’s nothing like real life to teach us lessons we couldn’t foresee with ice and wind farms.
The value of wind farms in icy locales
The abundance of strong winds across the Great Lakes creates opportunities to develop new technologies and engineer novel solutions to icy problems. As ice resides along Arctic coastlines, wind farm developments could bring clean power to remote communities that otherwise depend on fossil fuels for heating and light.
However, we can only figure out so much of what is on the drawing board. To understand the depth of the challenges of ice in offshore wind, people need to build wind farms and learn the lessons nature inevitably provides.
At PMI, we look forward to engineering rugged, high-performance subsea cable accessories that will be critical to the success of wind power in the Great Lakes and beyond.
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The corrosive effects of saltwater on subsea cables and accessories are well known.
Freshwater doesn’t have quite the same impact, but it still raises a range of issues for offshore wind developers. The saltwater vs. freshwater comparisons are becoming more relevant as offshore windfarm projects along the Great Lakes of North America — the largest expanse of freshwater on Earth — inch closer to reality.
Why the Great Lakes? Anybody who ever felt a summer gust from Lake Michigan in Chicago’s Loop or an icy blast from Lake Erie in downtown Cleveland understands. The vast open spaces of the Great Lakes allow strong Midwest winds to blow unimpeded.
Is it only a matter of time until the windfarms dotting the plains of North America extend to the Great Lakes? Perhaps, provided developers can apply the lessons of saltwater windfarms to the distinct needs of freshwater environments.
Saltwater challenges for subsea cables and accessories
Saltwater environments have specific impacts on subsea cables and accessories:
- Oxidation: Saltwater can corrode the surface of any metal. Carbon steel, for instance, is strong and cost-effective, but requires treatment to resist oxidation.
- Anodic corrosion: Because saltwater is an electrolyte, it triggers an electrochemical process at the contact points of dissimilar metals, such as cooper, magnesium, and carbon steel, that leads to corrosion.
- Live current: Subsea cables carrying current can generate electromagnetic fields of varying magnitudes. When the flow of water is perpendicular to the axis of the cable, the magnetic field begins interacting with seawater, or a charged object. There are variables which impact the intensity of the field which in turn impacts the amount of damage that can occur. Depending on the speed of saltwater passing over the cable, the diameter of the cable, and the amount of current, some high-velocity tidal areas can cause corrosion.
- Aquatic species: Barnacles, in particular, attach themselves to everything that goes in seawater. Once they attach themselves, they are extremely difficult to remove.
Freshwater challenges for subsea cables and offshore wind projects
Though freshwater is not nearly as corrosive as saltwater, it can be problematic in three ways:
- Ice: Each year, a significant portion of the Great Lakes is covered with ice, which complicates the construction offshore wind projects. During the winter of 2013-2014, 92% of the Great Lakes were frozen over. Companies in Scandinavia have figured out how to build towers in lakes that freeze, so ice need not be a deal-breaker in the Great Lakes.
- Pollution or foreign substances: Pollutants are wildcards in the construction of windfarms because it’s difficult to predict future pollution levels. Thus, engineering subsea cables and accessories to resist the impact of pollutants is imperfect at best.
- Human uses: The Great Lakes are busy shipping routes and recreational areas, and any offshore wind farm project would have to keep those factors in mind. Ships hauling goods and raw materials could potentially damage or threaten the electrical cables from freshwater windfarms. Boundaries would also have to be set up to prevent contact with boats and the people in them.
The power is there — the question is how we use it
The winds over the Great Lakes average 16 mph, according to the Natural Resources Defense Council. And governing bodies along the U.S. side of the Great Lakes are looking toward a future that includes windfarms, the Sierra Club notes on its website.
We mention these advocacy groups because they cautiously support windfarm development in the Great Lakes. Offshore windfarms attract well-deserved environmental scrutiny, but they still represent sources of clean, renewable energy sources for densely populated areas. The continued support of environmental groups will be key to the rise of offshore wind in the Great Lakes.
Power draw makes a case too. Summer months require more energy for climate control which can cause major outages when the grid is not prepared. Having an additional energy supplement will help prevent outages and make grids more reliable.
As we’ve noted many times in our blog, PMI is committed to supplying the rugged, long-lasting subsea cable accessories that windfarms need to defend their power lines against the subsea dangers.
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Synthetic cable is stronger than steel on a strength-to-weight basis, which makes it an attractive option in marine environments. The key challenge of synthetic cable is what you do about the attachment points, or terminations.
Terminations can cut the tensile strength of synthetic cable by more than 50 percent, potentially defeating the purpose of going with synthetic to begin with. However, a well-designed and properly installed termination can preserve more than 75 percent of the cable’s strength.
The termination must be installed by the manufacturer of the termination. It can’t be installed like a traditional steel termination can. That means if you’re ordering a volume of synthetic fiber cable, you need to ship it to your cable accessory supplier and have them cut your cable to length and attach the terminations.
Once the termination is in place, it’s there permanently. It cannot be removed. Hence it pays to be careful about your choice of synthetic cable termination provider.
Getting it Right with Synthetic Cable Terminations
Synthetic cables have a vast range of uses in subsea environments. They can do high-tech jobs like protecting fiber optic cables that transmit data around the world. Or they can do more mundane tasks like holding floating platforms in place.
Each of these jobs require terminations and other accessories that are engineered specifically to get the most performance out of the cable and preserve its strength at the attachment point.
At PMI, we’ve worked with clients in the subsea cable sector for decades, so we know exactly how to apply the right termination for each application. We have the specialized equipment required to perform synthetic terminations, and we have people trained to make sure the attachment is done properly.
And, of course, we supply some of the world’s best subsea cable terminations for all these varied applications.
Synthetic cables are less prone to corrosion and much more flexible and easy to use in chaotic marine environments. Many of them even float. But their unique chemical composition requires extra care at the termination point. Ignoring this risk could easily undo your entire investment in synthetic cables.
A trade association representing the subsea cable industry in the United Kingdom widened its focus in March 2016 to cover all of Europe.
The new European Subsea Cables Association (ESCA) takes the place of Subsea Cables UK. The trade group provides a forum for people who own, manage or service subsea telecommunication and power cables or serve the subsea cable industry in Europe and its surrounding waters.
ESCA’s prime goal is to encourage marine safety and help protect subsea cables from hazards such as fish nets, ship anchors and submarine landslides. The group also will defend the rights of operators to install and maintain underwater cable solutions.
“The requirement to form this new association has come from our membership and it was the logical evolution of the organization,” said Peter Jamieson of Virgin Media, chairman of the European Subsea Cables Association. “Close to 50 percent of the old UK association members were non-UK. Therefore, we can better serve our members by becoming a more regional association. ”
ESCA Executive Committee member Colin Rayman of Red Penguin Associates said that creation of the Europe-wide association will make it easer to confer with European maritime and fishing industry officials and government regulators “to move closer to attaining mutual understanding of our industries, sharing the seabed safely and maintaining the integrity of assets.”
The association will give its members advice and technical papers that will help everybody in the sector go about their business. Members of ESCA are experts in all phases of the subsea cable industry. They’ll convene bi-annually to share ideas and information.
If you’re in the submarine cable business, whether you’re an owner, operator, consultant, or subsea cable hardware supplier, you’re welcome to stop by the organization’s website at www.escaeu.org and download an application to join.
At PMI, we’re glad to see these people coming together to foster the health of the subsea cable industry across the European continent. Developments like tidal power and subsea power grids need consensus among business people and regulators to develop standards and hone technical expertise vital to the sector’s future.
As a premier provider of subsea cable hardware, we’re also on the front lines of Europe’s efforts to switch more of its energy consumption to renewable sources like wind power.
The offshore wind industry has fresh guidance on using reliable standards to determine the best depth for burying offshore wind farm cables.
In February 2016, the Offshore Wind Accelerator based in the U.K. published advice to offshore wind farm operators to help them ensure they are burying their power cables at a safe depth. This is a serious concern because power cable damage is one of the most common costs that threaten the success of offshore wind farms.
The advice is in the “Application Guide for the Specification of the Depth of Lowering using CBRA.” CBRA means “Cable Burial Risk Assessment Guidance” — which uses predictive modeling to help offshore wind operators get a greater handle on the risks of offshore cable burial. The hope is that CBRA will help the entire industry thrive by addressing the need for reliable, consistent cable-burial practices that are the standard across the industry.
Standardized offshore cable burial also can help fishing fleets, shipping lines and offshore oil developers reduce the risk that their operations will damage the cables tethered to offshore wind farms. Read more on the promise of new CBRA guidance in this update from Maritime Journal.
As a leading provider of subsea equipment, PMI is helping the offshore wind power industry address its cable safety concerns. Contact us for the facts on offshore wind cable hardware designed to withstand the rigors of the deep sea.
Have questions about your offshore wind power cables? Need tips on how to extend the life of your subsea cables? PMI has the answers – check out our free guide to Extending the life of you subsea power cables:
Whether they are lifting oil from deep below the seabed or experimenting with data centers on the ocean floor, anybody getting work done below sea level lives in perpetual fear of subsea equipment failures.
This is especially true as oil-development machinery equipment installed decades ago reaches the end of its projected operating life. What do you do with 20-year-old machinery that was built to last 20 years? Replace it now or wait for it to fail?
Either way, it will not be cheap. How can companies mitigate the risk of subsea equipment failures? A few tactics spring to mind:
Dive deeper into predictive maintenance
With today’s high-powered computers, databases, and networks, it’s getting much easier to collect data that will provide authoritative data on the likely expiration of subsea equipment. Of course this requires sensors that measure the conditions of equipment, and cabling to convey all that data to the surface.
It’s not an easy or a quick fix, but it should be built into any process of replacing or upgrading any new equipment being installed now. Forward-thinking drillers who do this today will reap far more benefits when oil prices inevitably recover.
Invest in more in-depth training
Subsea equipment fails for highly specific reasons that might be invisible to people who make routine checks and are trained to look for only a few data points. The key is to amass the knowledge of your most senior technicians and develop protocols to pass their advanced knowledge onto your junior technical staff.
Again, the oil market downturn can be a boon to advanced training because you can provide more in-depth training to smaller technical staffs. When repair and maintenance crews have to be ramped up in a year or two, you can implement your advanced training regimen to a wider audience.
Broaden your approach to integrity management
Integrity management has three anchors: inspection, maintenance and repair (IMR). You want to address all three holistically so that any change in one anchor is reflected in the others.
Deep-sea inspections can be logistically difficult and repairs can be disastrously expensive. That’s why so many companies are turning to data to help them understand the likelihood of failure so they can get every last minute out of a piece of subsea machinery but replace it before it actually fails and causes massive downtime or, worse yet, an environmental disaster.
There’s no question that all phases of IMR are costly, but the consequences of neglecting IMR are far worse. There will always be a temptation to cut corners on the quality of your subsea equipment, but these short-term savings can get extremely expensive if the equipment fails unexpectedly, endangering investments, ecosystems and people’s lives.
As a leading underwater engineering company, PMI has more than four decades of experience in creating subsea hardware for the oil and gas industry. Our track record of providing world-class cable hardware also can be a huge advantage companies in the emerging fields of offshore wind and tidal energy.
Want to learn more about deep-sea hazards? Download our Free Guide – the 6 types of corrosion that concern underwater engineering companies.
The island nation of Iceland has more renewable energy than it needs. Great Britain wants to use more power from renewable sources. A 1,000-kilometer submarine power cable could conceivably help Iceland export its surplus renewable power and help Great Britain meet its renewables goals.
All this is possible because of the advantages of high-voltage direct current (HVDC), which makes it more practical to transmit power over long distances via submarine power cables. Electrical grids around the world generally use alternating current (AC) because it’s more economical over short distances.
The problem with AC is it becomes less practical the farther the power has to be transmitted. When power has to be transmitted distances in measuring in the hundreds of kilometers or more, it becomes much more sensible to use high-voltage direct current.
Using HVDC to move lots of power over long distances is extremely helpful in developing nations like China that have rapidly emerging energy demands. But another of the great opportunities for HVDC lies deep below the ocean with subsea power cables.
Long-distance subsea power cables have a host of applications:
- Windfarms located far offshore. Wind is more abundant far away from shore, and many near-shore sites have already been developed. Submarine power cables using HVDC make these remote windfarms practical.
- Subsea electrical grids. Electrical grids beneath the ocean are being developed to improve the productivity of off-shore drilling operations. HVDC could allow them to be powered by production facilities on dry land.
- Metro areas where it’s impractical to build new power plants. In the San Francisco Bay Area, for instance, subsea power cables can extend power across the bay and avoid the need to build new power generating capacity.
This potential sounds awesome until you hear the statistics on how long it takes to repair a damaged submarine power cable. It can be days, weeks or months depending on the location and the severity of the damage.
The rugged reality of deep-ocean engineering is that it only takes one fishing trawler or cargo ship anchor to foul up a deep-sea power transmission plan. That’s why subsea cable protection is so important.
Providing that kind of protection has kept PMI in business for more than four decades, engineering rugged, durable ocean hardware for companies and projects around the globe.
Our deep ocean engineering experience helps enable the world-changing potential of renewable power. No matter how breathtaking the advances in technology, if the power has to be sent through subsea cables, those cables need extra protection that our ocean hardware provides.
Our guide, 6 Ways to Extend Your Subsea Power Cable Life, can provide more insight into increasing the longevity of your subsea cables. Download the free guide today:
