Lightweight ice-class vessels offer the possibility of increasing the payload capacity while making them comparable in energy consumption with non-ice-class vessels during ice-free periods. We approach the development of a lightweight hull by dividing ice–hull interactions into quasi-static loading and impact loading phases. Then, investigative outcomes of lightweight concepts for each loading phase may be combined to develop a lightweight ice-going hull. In this study, we focus on the quasi-static loading phase characteristic of thin first-year ice in inland waterways. We investigate metal grillages, sandwich structures and stiffened sandwich structures parametrically using the finite element method. The model is validated using previous experimental studies. In total over 2000 cases are investigated for strength and stiffness with respect to mass. The stiffened sandwich was found to be the most favorable concept that offered both a light weight as well as high gross tonnage. Further, significant parameters and their interactions and material differences for the three structural concepts were investigated and their trends discussed. The outcomes result in the creation of a viable pool of lightweight variants that fulfill the quasi-static loading phase. Together with outcomes from the impact loading phase, a lightweight ice-going hull may be developed.

With increasing need to utilize inland waterways (IWW), the design of IWW vessels gains attention both from a transport efficiency and an emission control point of view. The primary challenge is to estimate the ice pressure acting on the ship hull for IWW. Ice information for Lake Mälaren is extracted and analyzed in this work. Since the ice properties have great influence on the impact load, they are studied based on empirical formulae and are calibrated by reference data. The ice impact is then predicted for an IWW barge. Probabilistic method is selected to derive the load based on available field test data. Several parent datasets are chosen, and different design strategies are implemented to evaluate the ice impact load and investigate the influence from exposure factors. The paper finds that the design curve of α=0.265a−0.57 can be used for Lake Mälaren. The approach itself introduces a possible way to investigate loads on ice-affected IWW.

Urban water transit is undergoing a small renaissance as cities contend with increasing land-based congestion issues and promote waterfront development (1, 2). In Sweden, the expansion of passenger and freight uses on inland waterways is of interest to address congestion issues, but also to facilitate a new environmentally efficient transport option to reduce urban pollution (3, 4). However, there exist challenges in creating city-wide water transit systems in cities such as Stockholm. A recent International Association of Public Transport (UITP) report has shown how advances in urban water transit are generating patronage in Gothenburg, Stockholm and other water-based cities around the world (5). But there is limited detail on how Swedish systems are performing over time in terms of either patronage growth or generation of ferry-oriented development (FOD). By comparison, greater research effort has been placed on key Australian and U.S. urban water transit systems (2, 6, 7), which can offer insights beneficial to developing systems such as in Sweden. The focus of this paper is to outline the current scope of water transit operations, system planning and land development in Sweden, and to explore its prospects. To consider these issues and illustrate relative performance of Swedish systems, we make limited comparisons with well-established compatriot water transit networks in Brisbane and Sydney. The paper has three inter-related aims:

Within waterborne public transportation (WPT), one often observes a mismatch between the operational requirements and ferry characteristics. A method to holistically evaluate ferries with respect to local requirements could lead to tailored procurement and targeted refurbishment of existing fleet. In this study, we develop a structure for operational requirements and use it as a basis for a ferry evaluation methodology. The requirements’ structure follows a three-level hierarchy starting from broad vessel design to mandatory requirements to performance requirements. The performance requirements are based on the three pillars of sustainability, aided by commuter surveys carried out in Stockholm ferries, interviews with public transport providers (PTP) and previous literature. The evaluation of the ferry is performed using analytic hierarchic process (AHP) to convert the PTP’s subjective preferences and ferry performance into a single dimensionless index. Rules for quantification of performance metrics including social performance are proposed. The uncertainties associated with AHP are addressed by employing fuzzy AHP based on extent analysis and fuzzy AHP in combination with particle swarm optimization. Two applications including performance assessment of existing ferries and assembly of a modular ferry are discussed. The method can lead to objective decision making in ferry evaluation, potentially leading to a more efficient WPT.

Background: Among the challenges for implementation of Waterborne public transportation (WPT) are the difficulties in procuring efficient ferries tailored towards local requirements. Fundamental questions on the ferry’s environmental impact, speed and procurement costs linger in the public transport (PTP) mind. Objective: In this paper, a methodology for adopting a platform architecture for ferries is illustrated by a modular design approach. Methods: For this, WPT operational profiles are categorized by three route types in a structure for operational requirements including sustainability performance. Generic parameters for size and speed of WPT ferries are defined. Using these parameters as a skeletal structure, a modular commuter ferry concept is proposed as a set of basic modules. As a combination of these functionally independent modules, a ferry can be tailored to fit the operational requirements. Results: The paper proposes standard sizes for waterborne commuter craft and shows that ferries are compatible with land-based public transport in terms of energy efficiency and speed. Suitable speed ranges for mono hulls and catamarans are investigated and the idea of modular design for rational procurement is explored and illustrated for the three type routes. Conclusions: The proposed concepts can make WPT more attractive for PTPs as a sustainable option to complement the existing network.