Ship-bridge allision risk assessments often address either probability or consequence; integrations of both in a unified methodology are rare. This paper fills that gap by introducing Ship Traffic Allision Probability using Monte Carlo Simulations – consequence (STAPS-cons), a methodology where a mid-fidelity simulation methodology developed for probability assessment is used together with the results of Finite Element Analysis (FEA) simulations to include consequence assessments. Using Automatic Information System (AIS) data and the proposed methodology, a potential bridge over Norway’s Bjørnafjorden is analysed in a case study to determine the risk of structural collapse. The case study also illustrates how the risk is affected by different input parameters, both related to probability and consequence estimations. Five scenarios were analysed in this case study; three passed and two failed the Norwegian criterion for the probability of structural collapse, which is less frequent than 10−4 per year. A 20 % increase in the duration of a ship’s miss of turning point notably raised both the allision frequencies and the necessary levels of energy the bridge must withstand. In another scenario, where a less stiff bridge structure was analysed, the demand on the global structure decreased. In conclusion, the STAPS-cons methodology represents a significant advancement in the field of ship-bridge allision risk assessment. By integrating probability and consequence assessments, this methodology offers a more robust and comprehensive tool for managing the risks associated with increased shipping traffic and bridge construction in navigational waters.

The advances in civil engineering with novel bridge designs between islands and across fjords with long spans, increasing ship traffic density and larger ships in coastal areas, have resulted in an increased frequency of ship-bridge allision accidents worldwide. It is thus essential to have reliable models and methods for engineers to create safe designs of these new bridges to simulate and analyse early pro-active mitigation measures. This study presents a new ship traffic allision probabilistic simulation mid fidelity model (STAPS), which includes a ship's manoeuvrability and motion physics and uses the Monte Carlo simulation method in the probabilistic calculations. It is compared with the low fidelity model IWRAP Mk2, which is used to analyse the risk of ship allisions with structures. Two case studies with ship-allision scenarios are presented to compare how the model fidelity levels of STAPS and IWRAP Mk2 affect the calculated probability levels of ship-bridge allision events. On a general level, the results show that IWRAP Mk2 overestimates the accident probability, for example IWRAP Mk2 predicts a 4.5 times higher probability of allisions compared to STAPS in the base case, and that the failure's duration and route layouts significantly influence both models. The study concludes that IWRAP Mk2 is preferred in the early phase of bridge design and STAPS is preferred in later stages.

Wind propulsion systems (WPS) are major investments and the decision to install them requires careful consideration of many complex questions. In this paper we present a systematic, scientific methodology to assess the benefits and drawbacks of such systems at the early concept stage of a vessel. The purpose is to provide guidance for shipowners and operators and help them make informed decisions. The proposed method was developed into a Software tool called ‘SEAMAN Winds’ and has been correlated to full scale results. The program draws on our large database of model tests, and CFD of hulls and wind propulsion technologies. It uses the intended trading routes of the vessel as an important input, typical output data are: a) performance values (ship speed, power requirements etc.) b) environmental parameters (CO2 avoided, EEDI and EEXI reduction, carbon intensity indicator) c) financial metrics (bunker savings, payback time for installation of WPS) Potential applications of the method include making the business case for one particular WPS or investigating in how far certain systems are more suited for a specific route than others.

Designing sailing vessels for world-wide cargo transportation requires that the trade route and weather conditions are taken into consideration in the design process. This work studies various strategies for representing the weather distribution related to the expected operational profile. The balance between accuracy and design work efficiency for the different methods is discussed and demonstrated for a wind powered car carrier concept. © HPYD 2021.All right reserved.

Wind propulsion systems (WPS) are one of the most promising technologies for ship propulsion that can radically reduce greenhouse gas emissions. However, attention must be paid to the additional transversal forces and yaw moments connected to a wind propulsion system, as it can affect the manoeuvring and seakeeping performance of a ship. This paper demonstrates how time-domain simulations can be utilised to assess the manoeuvrability of a wind powered vessel to support the decision making, from the early design stage, all the way to testing the control systems, design of Human Machine Interface (HMI) and developing crew guidelines and training. The manoeuvre simulations are carried out with SSPA’s six degree of freedom inhouse code, SEAMAN-Winds. We present firstly a validation against manoeuvring model tests of a wind powered ship, where the wind propulsion units are represented by pulling fans. VPP calculations, which are commonly used in the early design phase, can predict the rudder angle required to balance the side force and yaw moment from the wind propulsion system. However, such steady-state computations provide no information on how robust this balance is when dynamic effects are present (e.g., wind gusts) and whether the balance can be regained if it has been momentarily lost. Therefore, time-domain simulations are shown to be useful to assess whether a ship can sail safely close to the limits of its VPP polars. Furthermore, it is demonstrated how mariners operating a real-time manoeuvre simulation tool can be utilised to increase the proof-of-concept, assess the HMI design, and for crew training.