Ship design for the Midway Alignment project has now reached an intensive phase. The Initial Design of the ferry was completed in April, and it is now followed by a more extensive and detailed chapter, the so-called Basic Design phase. Substantial parts of the ship’s concept have now been determined with the completion of this milestone. These are, for example, the vessel’s physical measurements, interfaces and other arrangements. As a result, the Initial Design phase forms a common baseline for further work with regards to the ship’s design as well as the land infrastructure’s planning and design.
– Low energy consumption is an important characteristic of the new ferry. In order to achieve this, a certain kind of comprehensive view is required. This applies particularly to the choice of components and the recovery of energy generated by, for example, waste heat from the engines or residual cooling from the evaporation of the onboard LNG, according to Mr Torvald Hvistendahl, Naval Architect at SSPA.
– However, the energy consumption is dominated by the ship’s propulsion. In order to minimize this aspect, we must optimize the hull form and the propulsion arrangements according to the ship’s specific operational profile. The maritime route between Vaasa and Umeå is full of challenges: the shallow waters, the necessity to be able to drive at different speeds so as to create an attractive timetable, the great variations in weather and wind conditions throughout the year, the occasional extreme ice situations, the numerous restrictions in the ports, and the varying loading conditions, Hvistendahl continues.
First tests in the Hull Optimization Programme were performed during week 19 in the open waters of SSPA’s towing tank in Gothenburg, Sweden. The tests were carried out with a seven-metre model dragged at various speeds, while the resistance was simultaneously registered with advanced measuring equipment.
A unique environment burdened with many challenges
The new ferry must operate in a rather unique environment, all in all. There are no standard solutions for an environment like this and, therefore, the project has chosen to implement a Hull Optimization Programme. This is a three-phase programme: the first phase involves the verification of the hull form created in the Initial Design phase, followed by an optimization accompanied with computations that will be subjected to a second round of tests. Based on this test data, the new ferry’s performance in its realistic operating environment and under harsh conditions (like strong winds) will be tested in “full mission simulations” concerning the arrival and departure to and from the ports.
– The first tests were performed during week 19 in the open waters of SSPA’s towing tank in Gothenburg, Sweden. The tests were carried out with a seven-metre model dragged at various speeds, while the resistance was simultaneously registered with advanced measuring equipment. The results were then proportioned to the actual ship with the help of standardized methods. This provides important input for further ship design and for the next phase in the Hull Optimization Programme, says Hvistendahl.
Potential for improvement and more tests in an ice basin in June
The first preliminary results indicate a somewhat lower power demand compared to the first estimates. The tests also reveal a number of details in the hull design that carry potential for improvement. In other words, it is still possible to improve the hull. Improvements surmounting to even a few per cents can lead to great economic and environmental savings.
The next phase in the Hull Optimization Programme involves similar tests with the same model in an ice basin. These tests will be carried out at Aker Arctic’s laboratory in Helsinki, Finland, in early June. We will be sure to tell our readers more about this in our next newsletters.