This paper presents a comparative study of computational fluid dynamics (CFD) and analytical and semiempirical (ASE) methods applied to the prediction of the normal force and moment coefficients of an autonomous underwater vehicle (AUV). Both methods are applied to the bare hull of the vehicle and to the body-hydroplane combination. The results are validated through experiments in a towing tank. It is shown that the CFD approach allows for a good prediction of the coefficients over the range of angles of attack considered. In contrast with the traditional ASE formulations used in naval and aircraft fields, an improved methodology is introduced that takes advantage of the qualitative information obtained from CFD flow visualizations.

The shipping sector decarbonisation has attracted great attention due to the sector contribution to worldwide carbon emissions. This study aims at investigating the techno-economic–environmental performance of different ship power plants to identify sustainable solutions for a case study cargo ship. Four scenarios, considering conventional and hybrid power plants, the latter with installed batteries, both using marine gas oil and ammonia fuels, are analysed to estimate the pertinent lifetime key performance indicators characterising their economic and environmental performance. Additionally, taxation schemes of varying extent are considered, and a sensitivity analysis is carried out on the most uncertain input parameters, namely, fuel prices and capital cost. This study results demonstrate that the hybrid plant using ammonia exhibits the lowest environmental footprint associated with 66% carbon emission reduction, whilst increasing the lifetime cost by 40%. Taxation schemes close to 340 EUR per CO₂ tonne are required to render it economically viable whilst meeting the IMO targets for 2050 on CO₂ emissions reduction. The sensitivity analysis reveals that the economic parameters is highly sensitive to fuel price and the capital expenditure.

Several major initiatives have been undertaken worldwide towards the development and commercialisation of maritime autonomous surface ships (MASSs). This study aims at capturing the current understanding and perspectives of the maritime industry stakeholders pertinent to the challenges and requirements for the design and operation of MASSs. A methodological approach consisting of five steps is followed. A questionnaire is developed and employed to conduct two surveys among the identified maritime industry stakeholders. Subsequently, the acquired response results are analysed, whereas statistical metrics are calculated and comparatively assessed using the box plot method, to provide evidence for identifying the perspectives and gaps from the considered stakeholders’ groups. Recommendations are provided for addressing these gaps, whereas further initiatives required in the maritime industry are also highlighted. This study contributes to the better understanding on the perspectives of the maritime industry stakeholders, whereas the results can support the prioritisation of future initiatives towards addressing existing barriers and overcome misconceptions for the next-generation autonomous shipping.