Copenhagen Subsea A/S is introducing a new standard for testing subsea thrusters
The new standard for testing subsea thrusters implemented by Copenhagen Subsea A/S dictates a remarkable 1,000 working hours of continuous operation at maximum power. Once tested and validated, the thruster must still maintain full functionality and unaffected performance.
When operating in open water, the cost of a failing subsea thruster is critical. Every malfunction, delay or maintenance-break related to the subsea exploration vessel will set back the entire operation. Imagine for a moment this critically expensive nightmare: the crew is standing idle on deck, looking out for the next ominous albatross to appear in the sky, while the mechanics work overtime to repair a defunct subsea thruster. Any responsible manager would go to great lengths to avoid this from happening on his watch.
At Copenhagen Subsea A/S, we realize that reliability is paramount when it comes to subsea thrusters. Right from the onset of our work, we have been striving to extend maintenance-free operating time well beyond 1,000 hours to secure optimal functionality for our customers.
Not only does the subsea industry demand extended operating time, our developmental process has also brought about green advantages: noiseless thrusters that operate 100 percent free from oil. At Copenhagen Subsea A/S, we realize that sustainability matters now and most certainly will matter in years to come.
Dedicated to Reliability
From an outside perspective, spending years on the constant development and improvement of an apparently finished product before even launching it may seem exaggerated. At Copenhagen Subsea A/S, however, we have chosen a focused and dedicated approach to improving the reliability and durability of our subsea thrusters. Right from the beginning of our development process, our mission has been to create a product that would change the way the entire industry thinks about subsea thrusters.
The reason behind this ambition is, in fact, simple: thruster breakdowns are extremely annoying and expensive, especially when operating in open water. Whole operations may suffer serious delays due to the malfunction of a single thruster. Furthermore, thruster downtime results in extremely high additional costs for ship-based operations – in fact, the costs of the ship, the crew and fuel by far exceed the costs of the underwater equipment: ROVs, manned submersibles and AUVs – all vessels dependent on reliable thrust.
To address this expensive and serious challenge inherently connected to subsea operations, we wanted to develop a thruster that would show a significant increase in durability. While the existing thrusters on the market show maintenance-free operating hours measured in the hundreds, we wanted to create a thruster that would yield optimal performance for at least one-thousand hours of continuous operation.
The 1,000 Hour Test
In our 10,000-liter test-tank located on our premises in Copenhagen, we perform a continuous test of our thrusters. 1,000 hours of operating time comprise 42 days during which the thruster operates 24/7 at maximum power. During this period, the thruster is constantly monitored for performance and energy consumption, and any deviance is registered.
When reaching the significant milestone of 1,000 operating hours, the thruster is carefully examined and, showing no signs of exhaustion or corrosion, allowed to continue operation in the test-tank where the thruster must maintain full functionality and unaffected performance.
The low margins in the oil and gas industry cause an increased focus on operational effectiveness. At Copenhagen Subsea A/S, we experience a strong demand for lower downtime at all levels of subsea operations. As part of this developing process that comprises the whole industry, we are determined to continuously improving the reliability and the performance of subsea thrusters.
Although our new 1,000 hour testing standard is still an unofficial one, the industry is clearly pressing for new and higher standards. With time, we expect the 1,000 hour test to become the valid standard for a new and updated certification of subsea thrusters. We are looking forward to such a certification and, following our results in this market, it is our ambition to lead subsea thruster performance and reliability to new highs.
Obsessed with Quality
At Copenhagen Subsea A/S, we are obsessed with the quality of our products. Based on several years of experience building vehicles to the subsea industry, we have too often felt the agony of low-reliability thrusters.
The thruster is just as critically important as any other component on board the subsea vehicle. For years, however, thrusters have suffered from having the lowest reliability factor among vessel components. Thus, the thrusters have become the weakest link in the chain of operation - with considerable maintenance costs as a result.
At Copenhagen Subsea A/S, we realized that this was a field open for a substantial rethinking and development process. In order to meet the industry’s new and higher demands for reliable thrusters and decreased operating costs, our solution was to construct our own new product-line of subsea thrusters. Utilizing the innovative ring thruster technology, we have been able to show a significant increase in reliability.
The strong focus on reliability quickly made it clear that conventional thruster technology could not be used. Conventional subsea thrusters use a fluid inside the thruster to compensate for the surrounding water pressure. This method has been refined over the years, but it is still far less robust than the goals we set for this project.
The process of starting from scratch and searching for a disruptive technology took a long time, but it has been worth the effort. Today, our products have reached a high level of reliability – they live up to a new standard, which is in fact in a league of its own. Based on empirical data from users and the thrusters we have tested in our 1,000 hour paradigm, our reliability rate is an order of magnitude better than that of conventional thrusters.
Positive Side Effects: The Green Advantage
Conventional thrusters use oil lubrication for mechanical parts and for pressure compensation in the cavity between the rotor and the housing. In contrast, our thrusters use only the surrounding seawater. Manufactured as a unit of two solid molded parts, there is no enclosed space or cavity in the thruster that needs pressure compensation. One of the advantages in relation to conventional thrusters, which use a fluid for pressure compensation, is of course that the new solution is 100 percent pollution-free and spillage will never occur.
What is even more surprising, however, is that water functions as good as, or even better, than oil in the permanent and necessary lubrication process in the operating thruster. In his groundbreaking article ‘Water lubricated bearings,’ S. Hother-Lushington concludes that: “Provided the bearing and its lubrication system are designed properly, the reliability of a water lubricated bearing should be as high as or higher than the more conventionally lubricated bearing (and seal) which it replaces” (Tribology International, volume 9, issue 6, 1976).
Reliability and sustainability – these are keywords at Copenhagen Subsea A/S.
The world has already seen its fair share of oil catastrophes. The images of BP’s burning Deepwater Horizon platform in the Mexican Gulf in April 2010 make it clear that the efforts to become greener must affect all industries.
As the world moves toward a greener future, we expect our customers to demand still more reliable and sustainable products. Accordingly, our mission is to develop and manufacture subsea thrusters that will lift the state of the art to unprecedented levels.
Copenhagen Subsea A/S has already had tremendous success with the market entry of their subsea thrusters. Our subsea thrusters were, after years of development and test, introduced to the market in October 2015. Beside the unique features of the powerful thrusters – such as low noise and no risk of entanglement – we have been overwhelmed with interest from customers wanting to increase the reliability of their vehicle propulsion system.
Customer applications in the subsea industry ranges from ROV, manned submersibles and AUV. The customers continue to return to us for discussions regarding robustness, maintenance and spare-part strategies.
These are all issues related to reliability, and they are indeed the most important concerns that our customers express. To us, these discussions confirm that we have applied a solid strategy when investing so much energy in developing reliable thrusters to meet the demands of an industry that is becoming increasingly aware of the efficiency of the thruster in subsea exploration.
Right from the beginning of our development process, we have been convinced that we needed to aim for ambitious goals. Goals that would distinguish us from all other manufacturers of subsea thrusters. By producing evidence that we have fulfilled this goal, we have reached an unprecedented and remarkable milestone in the process of improving reliability, sustainability and reducing maintenance costs in the subsea industry.