From Ship to Ship to floating wind

Continuous improvement, innovation and safety lie at the heart of Ampelmann. Though ship to ship (S2S) operations – from one moving vessel to another – have long since been part of the company’s remit, it has become more relevant than ever. Driven by the desire to better serve the FPSO market on the one hand, and the emerging floating wind market on the other, providing safe and reliable access between two floating objects has become a core focus point of the company. Today, Ampelmann is rigorously trialling its motion compensated systems to prepare for an increasing number of S2S work scopes.

Ship to Ship

Yonna Welschen joined Ampelmann over seven years ago as a mechanical engineer and is now Team Lead of the Improvements department at Ampelmann, a role she created herself. In her own words, “I ensure that projects are prioritised and that the right people are on those projects. We receive improvement requests for the existing fleet from all over the company and make sure that we provide the necessary maintenance documentation and operational support.”

Having fulfilled multiple roles during her career at Ampelmann, including as Project Manager for Special Projects, member of the Operation Control Centre (OCC) and Project Manager at Innovations, she has been consistently involved in modifying and enhancing the company’s gangways. For the last four years, one her responsibilities has been improving the S2S capabilities of the systems, with specific focus on the L-type - Ampelmann’s electric gangway system designed for continuous crew change operations that require quick and flexible mobilisation.

S2S operations are technically challenging because in addition to motion compensating for unpredictable wave conditions, the divergent motions of two moving objects need to be offset in order to guarantee safe and consistent access to personnel and cargo. “Over the years,” says Yonna, “the technology has changed, but we’ve always received a lot of requests about our S2S capabilities. I’ve been involved in this since the day I started to work for Ampelmann, but when I moved to Improvements, I became especially entangled with the technical side of it.”

Most of Ampelmann’s gangways have the capacity to carry out operations that require the transfer of personnel or cargo from one floating object to another. For many years, the company has enabled operations between vessels as well as larger floating objects such as FPSOs, Spars, semi-submersibles, single point moored buoys (SPM) and, since early 2020, floating wind turbines. Anticipating the growth of these markets, Ampelmann is examining and improving upon the S2S capabilities of its gangway systems.

“Because we work from project to project,” Yonna continues, “our improvements are driven by our clients’ wishes, as much as they are by our desire to innovate and to provide safe offshore access. Over the years, we have made adaptations to our gangways, among which are newly designed landing zones and gangway tips that we developed to enhance the performance of our systems during S2S operations. For our A- and E-types, we developed the V-shape, a landing zone that is installed on the receiving vessel. As it locks the gangway’s tip into place whenever it wants to move, it helps to counteract the excessive motions of two moving objects or vessels.”

Improving the L-type

Following the trend to trial and enhance each system, Yonna has devoted special attention to improving and testing the S2S capabilities of the L-type. As she explains: “We received a lot of requests regarding its capacity to transfer personnel between two floating objects. We decided to put this to the test and examine and trial the gangway to determine under which conditions it is capable to perform such operations. Theoretically, there is no major difference between the S2S operations of the L-type and our other systems that we had previously tested in Portugal. Rather, this project was more about determining the exact conditions in which we can operate, measuring whether our predictions were correct and finetuning our operational guidelines.”

The trials were completed on 14 May 2023 and the data has now been fully analysed and evaluated. “We started this project to establish that the L-type can handle the speeds and accelerations during S2S operations," says Yonna. “Because a vessel with a mobilised L-type makes a pitching motion while the receiving one makes a rolling motion, the accelerations that the gangway must be able to handle for telescoping and luffing are much higher than if one of the two is stationary. As the L-type is much smaller than our other systems compensating for the relative motions between two moving objects is much more challenging. Now that we have analysed the data, we have proven that the gangway is able to function accordingly on such operations and, as we expected, these were very successful trials.”

“From a technical perspective, we did not need to make major adaptations, neither to the hydraulics, mechanics, nor the software, as our gangways can already handle a lot on their own. Instead, we gained valuable insights about the required specifications and ideal positioning of the vessels, as much as a better understanding under which conditions the L-type can perform S2S operations. As such, we know how to optimise the safety and efficiency of these operations.”

Nevertheless, Yonna and her team made several key innovations to the design and operation of the gangway to further enhance its performance during S2S operations.

“We implemented alarms that go off whenever high speeds and accelerations are reached, like we did for the A-, E- and S-type. In addition, we developed a new landing zone for the L-type to reduce the vibrations caused by the divergent motions of two moving objects and our trials have shown that this greatly decreases the residual motions caused by localised sea conditions.”

Floating wind and Ship to Ship

Yonna expects such technology to be increasingly relevant in the years to come, adding that continuous development and close cooperation will be necessary in order to serve the changing needs of the emergent floating wind market. Like S2S operations, floating wind scopes require access solutions that can safely and reliably facilitate offshore operations in spite of weather conditions and constraints imposed by the divergent motions of vessel and floaters.

Yonna points out that there are many similarities between S2S operations and those between vessels and floaters, but there are also some key differences.

“An FPSO, for example, can be relatively stationary because of its size and bulkiness. However, the flotations of these turbines are akin to those of a duckling at sea. There are a lot more movements that need to be taken into account and, of course, you can’t communicate with a turbine like you can with another vessel. Usually, we perform S2S operations while landing our gangways on the leeward side of a floating structure which means we mainly have to compensate for rolling motions. Yet, because floating wind turbines have different, and frequently irregular, shapes, the motions are far more unpredictable and require a different approach. It also really depends on the type of floater and the mooring system. Tension leg turbines are very different from those that are attached to the seabed with slack catenary lines. Not only are the motions different, but the access points to the floater differ. These are especially important because they determine how and where we can land, and from what angle the turbine can be approached.”

Such additional challenges will require close cooperation between all the stakeholders, particularly when it comes to offshore access. Ampelmann has been involved in the floating wind sector since 2020, and more recently during the world’s first commercial construction project at Hywind Tampen. As Yonna emphasises: “Not only do we find it important to be involved in the early stages of this expanding market, but we need to let potential clients know that we find it equally important to think along as it develops. Because we train our own operators and have a large rental fleet, we are closely involved with the projects we carry out. We thought along during the development of ordinary bottom-founded turbines and our landing zone designs, for example, see much use in the offshore wind sector. We are already thinking about new innovations that can help make accessing floating wind turbines as easy as crossing the street.”