National and international governmental bodies have set high goals for reduction of harmful emissions from ships. The International Maritime Organization (IMO) has established the Energy Efficiency Design Index (EEDI) as the major policy measure to reduce greenhouse gas (GHG) emissions from shipping. The EEDI restricts a given vessel to a maximum level of emitted grams of CO2 per ton-mile. The EEDI requirements could be achieved by simply reducing the installed engine power. Doing so leads to compromises in the ship's ability to maintain manoeuvrability and safety in adverse conditions, due to insufficient propulsive power and steering capabilities.
The ongoing international regulatory work prioritises emission performance in calm water, with a risk of "Green" vessels being sub-optimally designed. Hence, there is an urgent need for additional understanding of the effects on propulsion performance and manoeuvrability in waves. Ship designers need better tools to study these effects, to ensure that future ships are designed for safe operation in realistic sea conditions and with minimum emissions.
The SEAWORTHY project will address these needs by investigating - through interviews and workshops with operators, shipmasters and designers - operational challenges experienced with "Green" vessels. Specific needs for improved software tools, for various design phases and for ship operation, will be identified. Next, based on existing methods and software tools, new an improved tools will be developed and tested by the industry participants. Scale-model experiments and measurements onboard a real vessel in operation will be used to gain insight into relevant physical phenomena and for validation of the software tools.
Two vital problems have been identified through discussion with partners. These relate to sharpening the focus of ship owners and maritime administrations on fulfilling greenhouse gas (GHG) reductions, in line with national and international goals. Firstly, the typical approach of following EEDI guidelines promotes a specialised fleet of ships which are specifically designed to meet the guidelines themselves, while offering only marginal real GHG reductions. Secondly, the promotion of ships with smaller engines for the reduction of fuel consumption can achieve the opposite. Furthermore, underpowered vessels may not be sufficiently seaworthy in adverse weather conditions. This leads to poor manoeuvrability and seakeeping properties along with higher energy consumption in realistic seagoing conditions.
The project will test and develop numeric and experimental tools used in studying the operational challenges associated with unconventional low-emission vessel designs. Numerical methods will be further developed for use in design work for such vessels. Based on operational experience, gained by officers on ships designed for low GHG emissions, officers and researchers will collaborate to provide pilot versions of onboard decision support systems for improving situational awareness and operability.
An open benchmark vessel, developed by SINTEF Ocean, will be used as test case for comparison of numerical and experimental hydrodynamic methods to investigate operational performance parameters for new low-emission ship designs. Experimental work will apply captive and free-running model tests at the participating laboratories. The results will be used in validation studies and as part of PhD activities. For studies of operations in real seas and adverse conditions, operational data collected from Eidsvaag Pioner will be used for validation of numerical tools and for ensuring that selected motion parameters are satisfactorily represented in physical model tests.