Fulfilment of the progressive environmental normative involves a singular challenge for Short Sea Shipping (SSS), since it must maintain its competitiveness versus other transport alternatives. For this reason, over the last decade SSS vessels have been the subject of numerous analyses, in terms of operative research, and optimizations, from the marine engineering standpoint. Despite widespread awareness about the impact of a vessel’s resistance on environmental performance, many of the previous analyses were based on resistance prediction methods with low accuracy levels. This fact necessarily involves deviations regarding the expected sustainability of vessels. This paper attempts to quantify (in monetary terms) the environmental consequences due to this low level of accuracy. To meet this aim, it analyzes the environmental performance of an SSS feeder vessel, which was obtained from an optimization process based on standard resistance prediction techniques, when its propulsion power requirements for sailing at optimized speed were assessed through the Reynolds Averaged Navier–Stokes method in Computational Fluid Dynamic simulations. The findings show that standard resistance prediction methods without consideration of hull shape must be avoided, not only in the optimization process, but also for operative research, especially in free sailing analysis.

This paper introduces a mathematical model to assess the polluting impact of the decarbonization options for medium-sized High-Speed Crafts in the EU, and their consequences in terms of Market-Based Measure costs and Goal-Based Measure compliance under expected regulatory scenarios. This model is applied to a particular European High-Speed Craft operating in the Canary Islands. Considering slow steaming along with High Speed Craft’s retrofitting with alternative technologies for its electricity supply, we conclude that green H₂ fuel Cells provide the greatest environmental advantage by comparison with slow steaming alone, achieving a 6.96% improvement in emissions and savings under European Market-Based Measures of 39.76% by 2033. The expected regulative progression involves a 5.90% improvement in the Market-Based Measure costs’ convergence with the actual pollution impact of High-Speed Crafts. The findings warn about the pressing need to review the implementation of On-Shore Power Supply emissions into the Fuel EU fines, and about a concerning pull effect for the most polluting European High-Speed Crafts are moved towards the outermost regions of the EU due to their permanent exceptions from the application of the European Market-Based Measures.

The paper analyses Under-Water-Noise (URN) mitigations provided by strategies adopted by High-Speed Crafts (HSC) to meet Carbon Intensity Indicator (CII) in the EU. The paper introduces a mathematical model to quantify jointly the HSC pollutant impact by air emissions and URN in monetary terms. Parallelly, resulting EU Market-Based-Measures (EU-MBM) and URN taxes proposed by this paper, through ECHO program’s adaptations to Short-Sea-Shipping, are modelled. The suggested URN charging system offers proportionated taxes to the URN reductions. The model’s application to an HSC in the Canary Islands, provides URN contributions up to 35% on the total pollutant impact of the HSC. Additionally, replacing on-board generating sets by green H2 fuel cells along with slow teaming, URN mitigations up to 58% were achieved. However, these mitigations involve environmental benefits of 8.8% due to an insufficient knowledge about the marine mammals’ number affected by port operations and the thresholds for noise’s adverse effects.