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. In this paper, a methodology for adopting a platform architecture for ferries is illustrated by a modular design approach. 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. 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. The proposed concepts can make WPT more attractive for PTPs as a sustainable option to complement the existing network.

The current study focuses on the impact loading phase characteristic of thin first year ice in inland waterways. We investigate metal grillages, fibre reinforced plastic (FRP) composites and nature-inspired composites using LS Dyna. The impact mode is modelled as (a) simplified impact model with a rigid-body impactor and (b) an experimentally validated ice model represented by cohesive zone elements. The structural concepts are investigated parametrically for strength and stiffness using the simplified model, and an aluminium alloy grillage is analysed with the ice model. The metal–FRP composite was found to be the most favourable concept that offered impact protection as well as being light weight. By weight, FRP composites with a Bouligand ply arrangement were the most favourable but prone to impact damage. Further, aluminium grillage was found to be a significant contender for a range of ice impact velocities. While the ice model is experimentally validated, a drawback of the simplified model is the lack of experimental data. We overcame this by limiting the scope to low velocity impact and investigating only relative structural performance. By doing so, the study identifies significant parameters and parametric trends along with material differences for all structural concepts. The outcomes result in the creation of a viable pool of lightweight variants that fulfil the impact loading phase. Together with outcomes from quasi-static loading phase, it is possible to develop a lightweight ice-going hull concept.

Waterborne public transportation (WPT) is slowly increasing in importance as an active component of public transportation networks in cities. City planners are looking at WPT to overcome urban congestion and pollution. However, prevalent challenges like ferry procurement, poor state of existing ferry fleets and technical challenges like the presence of ice, have created reluctance in the minds of public transport providers (PTPs).  While contemporary research shows ferries can be economical and environmentally friendly, there are some fundamental challenges that need to be addressed before PTPs can feel confident.

In this regard, deterrents from PTP’s perspective are identified and solutions are investigated, starting with a systematic characterization of WPT. A definite structure for operational requirements is proposed in an objective manner. Using these as basis, two standard ferry sizes that could fulfil multiple WPT roles in majority of cities are introduced. For establishing city-wise tailoring, platform-architecture based modularization of ferries is proposed. The ferry modules are tailored with respect to operational requirements in a clear and objective manner through the introduction of an evaluation methodology. The method incorporates economic, social, environmental, and regulatory stakeholders. These proposed solutions are aimed at improving PTP’s confidence in WPT and provides solutions for the marine industry to produce quick, cost efficient and tailored ferries. 

Next, the scope is focused towards investigating sustainable operations in freshwater ice conditions, typically found in the Stockholm region in Sweden. The ice going ferries today operate with ice strengthened heavy hulls. While they work well in ice, they perform poorly in comparison with non-ice going ferries during ice free months. Correspondingly, solutions towards lightweight ice going hulls are investigated. 

This investigation starts with understanding ice-hull interaction mechanisms. Then, techniques to estimate the ice loads are investigated. We adopt a probabilistic approach to tackle the limitations due to the stochastic nature of ice and a lack of experimental data. The resulting load cases are used for evaluating lightweight structural concepts. 

The investigation is approached by dividing ice-hull interaction into quasi-static, dynamic and abrasive loading phases. Several candidates corresponding to the first two loading phases are investigated parametrically. The range of structural concepts include metal grillages, bio-inspired composites, and sandwich structures. Realistic loading models for quasi-static and impact mechanisms are developed and validated with experiments. The winning candidates for each loading phase are combined to propose a tri-layer lightweight structural concept. Three candidates for the concept are evaluated and compared.

The thesis answers several questions that riddle WPT today. But at the same time, it raises new questions. Several directions for future work are identified. With continued development, it would be possible to see modularly tailored ferries operating with lightweight hulls in WPT systems around the world.

Vattenburen kollektivtrafik ökar i betydelse som en aktiv komponent i kollektivtrafiknätverk i städer. När trängsel och föroreningar ökar i städerna, börjar stadsplanerare se på vattenvägarna. Men utmaningar när det gäller färjeanskaffning, nergångna befintliga färjeflottor och tekniska utmaningar som is på vintern, har skapat motvilja hos kollektivtrafikleverantörer. Forskning visar att färjor kan vara både ekonomiska och miljövänliga. Inte desto mindre finns det grundläggande utmaningar som måste hanteras innan kollektivtrafikleverantörerna känner tillförsikt. För att möta detta identifieras de avskräckande utmaningarna och lösningar undersöks inledningsvis med att systematiskt karakterisera den vattenburna kollektivtrafiken. En bestämd struktur för verksamhetskrav föreslås med objektiva mått. Med dessa som grund introduceras två standardfärjestorlekar som skulle kunna fylla flera transportroller i städer med vattenvägar. För att möjliggöra skräddarsydda lösningar i olika städer, etableras en mudulariserad plattformsarkitektur för färjorna. Färjemodulerna skräddarsys med hänsyn till operativa krav och granskas objektivt med hjälp av en utvecklad utvärderingsmetodik. Metoden omfattar ekonomiska, sociala, miljömässiga och regelverksaspekter. Metodiken syftar till att förbättra kollektivtrafikleverantörernas förtroende för vattenburen kollektivtrafik och föreslår också lösningar för den marina industrin för snabb produktion av kostnadseffektiva, skräddarsydda färjor.

I nästa steg studeras frågan om hållbar sjötrafik vintertid. Fokus är sötvattenis typisk för Stockholmsregionen i Sverige. De isgående färjorna i trafik idag har isförstärkta tunga skrov. Även om det fungerar bra när det är is, presterar de dåligt i jämförelse med icke-isgående färjor under de isfria månaderna. Detta motiverar utveckling av lätta isgående färjor. Undersökningen inleds med studier av interaktionsmekanismerna mellan is och skrov. Därefter undersöks metoder för att uppskatta isbelastningarna. Här hanteras flera begränsningar, kopplade till brist på experimentell data och isens stokastiska natur, med hjälp av en probabilistisk metod. Metoden tillämpas för att generera designlastfall för undersökning av olika lätta konstruktionskoncept. Undersökningen delar upp is-skrovinteraktionen i kvasistatiska, dynamiska och abrasiva belastningsfaser. Flera kandidater för de två första faserna undersöks parametriskt. Valet av strukturkoncept omfattar metallstrukturer, komposit- och sandwichstrukturer. De är valda utifrån nuvarande designpraxis och med varianter inspirerade från naturen. Realistiska modeller för kvasistatiska- och stötbelastningar utvecklas och valideras med experimentdata. De bästa strukturvarianterna för respektive belastningsfas kombineras till förslag av lättviktskonstruktion i tre lager. Tre sådana strukturvarianter utvärderas och jämförs.

Avhandlingen svarar på flera frågor som idag hämmar vattenburen kollektivtrafik. Den väcker samtidigt nya frågor och flera riktningar för framtida studier identifieras. Slutsatserna belyser möjligheten för modulärt skräddarsydda färjor med lättviktsskrov att operera i den vattenburna kollektivtrafiken runt om i världen.

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.

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.

There has been a recent surge in interest in waterborne public transportation (WPT). Publictransport providers (PTP) are seeing its potential in complementing the existing transportnetwork and alleviating urban traffic congestion and pollution. But the adoption of WPTtoday is challenging due to a series of technical and implementation challenges. Thesechallenges include ferry procurement practices, local legislation and policies andenvironmental factors like winter ice. Several of these challenges can be alleviated if efficientferries can be made accessible off-the-shelf with a low manufacturing time and cost. Thethesis focuses on developing such a ferry concept based on modular design whose overalldimensions are standardized and internal arrangement is customizable towards operationalrequirements, with a focus towards sustainable and safe operations in ice.Starting with the characterization of WPT, ferry routes are broadly classified into three types.These routes are described with an operational requirements framework considering allrelevant stakeholder expectations. Then, overall dimensions of vessels representative ofWPT are deduced. Using these dimensions to standardize the overall dimensions, a modularferry concept is developed as an assembly of modules and submodules. The modules arepresented as standardized units having fixed dimensions and interfaces whose internalarrangements can be tailored to meet operational requirements. Design standardizationlowers costs and manufacturing time while internal customization favours tailoring the ferryconcept. One challenge associated with this for the PTP is the difficulty in choosingappropriate modules among multiple alternatives. This is overcome through thedevelopment of a ranking and selection method which benchmarks competing designs andhelps in decision making.In terms of technical challenges for the developed ferry concept, cities like Stockholmexperience freezing of water bodies during winter months. For reliable year-roundoperations that are safe and sustainable in terms of economy and environment, there is aneed for the development of lightweight and robust ice going hulls. This thesis lays thefoundation for the development of such hulls by studying the prevalent ice data and proposesa probabilistic method for estimating the design ice pressures.One must rely on probabilistic methods since most experimental studies are based on seaice whose mechanical properties are different from freshwater ice, which is typical for WPT.Traditionally, classification society rules like the Finnish Swedish Ice Class Rules are usedfor first year light ice conditions which were developed for the Baltic Sea consideringicebreaker vessels. They work well in ensuring a safe design, but their performance forfreshwater ice, applied to commuter ferries have not been tested. Therefore, a probabilisticapproach is adopted where the unknown parameters are incorporated as random variables.The probabilistic method reduces the hull-ice interaction to a pressure and contact-arearelationship. With arctic datasets that closely match WPT conditions as the parent dataset,the probabilistic method is calibrated with exposure conditions for WPT to give the designpressure-area curve. The different uncertainties arising from operations in ice are studied using a statistical tool and the leading source of uncertainty is attributed to ice-loadprediction methods. This establishes the need for more robust methods for prediction of iceloads so that a lightweight, yet robust hull may be designed which is efficient in terms of fueleconomy and emissions.WPT presents a tremendous opportunity in complementing the existing transport network.With careful design and development of the modular ferry concept and its technicalchallenges, it would be easier for PTPs to adopt WPT globally.

De senaste decenniet har intresset ökat för kollektivtrafik på vatten (WPT).Kollektivtrafikleverantörer ser potential att minska trängsel och utsläpp och tillförakapacitet genom att utnyttja de urbana vattenvägarna. Men realiseringen har utmaningar,så väl tekniska som relaterade till regelverk och systempraxis. Dessa omfattar inköp av färjoroch upphandling av vattenburen trafik, lokal lagstiftning och policyer, miljöfaktorer ochdessutom isen vintertid. Flera av dessa utmaningar kan hanteras om effektiva färjor kangöras lättillgängliga med kort tillverkningstid till ett pris i paritet med övrig kollektivtrafik.Avhandlingen fokuserar på att utveckla ett färjekoncept baserat på modulär design medövergripande, standardiserade, dimensioner och med möjlighet att anpassa inredningenefter operativa krav.Efter karaktäriseringen av WPT klassificeras färjerutter i tre kategorier. Dessa rutterbeskrivs i ett operativt ramverk som beaktar relevanta intressenters förväntningar. Därefterbestäms de övergripande dimensionerna för WPT fartyg. Baserat på dessa utvecklas ettmodulärt färjekoncept som en sammansättning av moduler och delmoduler. Modulerna harstandarddimensioner och gränssnitt så att arrangemang kan skräddarsys för att uppfyllaaktuella operativa krav. En utmaning med det modulära färjekonceptet är svårigheten attbedöma vilken kombination av moduler som är bäst när det finns många möjligakombinationer som uppfyller en kravprofil. För att hantera detta utvecklas en rankningsochurvalsmetod för att kunna jämföra konkurrerande lösningar och därmed ge stöd i valetav design.En teknisk utmaning i städer som Stockholm är isen vintertid. För tillförlitlig trafik, åretrunt, som är både säker och hållbar, ekonomiskt och miljömässigt, finns det ett behov avutveckling av lätta och starka skrov som tål att operera i is. Avhandlingen närmar sigutvecklingen av sådana skrov genom att föreslå lämpliga isdata och en sannolikhetsbaseradmetod för att uppskatta dimensionerande isbelastningar.Is för nordiska WPT förhållanden är vanligtvis sötvattensis, vars mekaniska egenskaperskiljer sig från havsis. De flesta studier som beskriver isegenskaper är experimentella ochbaserade på havsis där man måste förlita sig på probabilistiska metoder för att ta hänsyn tillosäkerheter. Traditionellt används regler från klassificeringssällskap, som de finsk-svenskaisklassreglerna FSICR för första års isförhållanden vilket utvecklats för Östersjön ochisbrytande fartyg. Reglerna fungerar för att säkerställa en säker konstruktion men hur välde är anpassade för att dimensionera effektiva pendelfärjor i sötvattenis har inte utretts. Iavhandlingen antas ett probabilistiskt tillvägagångssätt där de okända parametrarna antassom slumpmässiga variabler. Den probabilistiska metoden förenklar interaktionen mellanskrov och is till ett förhållande mellan tryck och kontaktyta. Med publicerad data, som näramatchar WPT-förhållanden, som bas, kalibreras den probabilistiska metoden tillexponeringsförhållanden för WPT för att formulera den dimensionerande tryck-kurvan. Deolika osäkerhetsfaktorerna vid operation i is studeras med statistisk analys som visar att denfrämsta källan till osäkerhet är just förutsägelsen av isbelastningen. Detta fastställer behovet av mer robusta metoder för förutsägelse av isbelastningar så att ett lätt, men ändå starktskrov kan utformas som är effektivt med avseende på bränsleekonomi och utsläpp.WPT ger stora möjligheter att komplettera ett befintligt kollektivtrafik nätverk. Mednoggrann design och tillämpning av det modulära färjekonceptet kan det bli enklare att tatillvara möjligheterna runt om i världen.

For ships running on ice-covered waters, the ice impact load on ship structure shall be carefully considered. This paper proposes an analytical model which takes two most important ice failure modes, localized crushing and bending breaking, into consideration. The energy method is introduced to estimate the crushing force and the indentation displacement for different scenarios. Ice bending breaking scenario is simplified as a semi-infinite plate under a distributed load resting on an elastic foundation. The two ice failure modes are assumed to share the same contact area. This model is useful to predict the ice impact load and creates a bridge between design parameters (ice properties and ship geometry) and structure loads. 

There has been an increased awareness of the benefits of utilizing inland waterways (IWW) from a transport efficiency and an emission control point of view. However, due to presence of ice in water bodies, vessels designed for non-ice river operations cannot operate during the winter months. This paper analyses a grillage representative of barge’s bow region using non-linear finite element analysis (NL FEA) and assesses survivability in comparison with load limits prescribed by latest Finnish Swedish Ice Class Rules (FSICR) 2017 rules, International Association of Classification Societies (IACS) Polar Cass 6 (PC6) rules and simplified plastic collapse limit states calculated by Daley (2002). The NLFEA study included strength contributions from strain hardening and membrane stress and it was found that the limit state described by rupture stress was significantly larger. It was found that allowance for plasticity can reduce structural scantling requirements for fresh water ice operating vessels. The study also validated latest FSIRCR 2017 requirements.

Increased urban congestion in cities has led to suggestions for the greater use of inland waterways for passenger transit. However, there has been relatively little exploration of how water transit differs in terms of passenger service attributes compared to other transport modes and how passenger attitudes toward water transit service factors may affect overall satisfaction. The present study attempts to address this gap in knowledge in a study of water transport users in Stockholm, Sweden in order understand how water transit fares compared to other modes. Building on the literature of attitudinal studies for other transit modes, a survey was conducted in the Stockholm metropolitan area of water transit users on the primary inner-city water transit route. Details on trip characteristics, demographic and passenger's attitudes toward service attributes and their satisfaction was collected. After factor analysis, a structural equation model is proposed to explore the impact of service characteristics on global customer satisfaction. The results indicate that the latent factor comfort, including indicators such as cleanliness of vessel and environmental and scenic factors were more significant in explaining overall passenger satisfaction, above service issues such as network size and frequency. The finding supports the growing body of research highlighting the importance of such experiential factors in explaining customer satisfaction within public transport. Greater incorporation of such non-traditional service attributes can therefore give a better picture of transit user mode choice behavior and aid in future service planning ongoing policy development of the water transit network in Stockholm.

With increasing need to utilize inland waterways (IWW), the design for IWW vessels gains attention both from a transport efficiency and an emission control point of view. The primarily issue is to estimate the ice pressure acting on the ship hull for inland waterways. Ice information for Lake Malaren is extracted and analysed 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 inland water 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 influences from exposure factors. The paper finds that the design curve of alpha = 0.265a(-0.57) can be used for Lake Malaren. The approach itself introduces a possible way to investigate loads on ice affected IWW.