International Journal of Maritime Engineering

Ship Collision Avoidance Decision-Making Using an Improved Black Widow Optimization Algorithm

Dongxing Xu, Jianchuan Yin — Mon, 07 Sep 2026 00:00:00 +0100

In order to enhance intelligence and acquire the effective avoidance angles of the ship collision avoidance system, an improved decision-making scheme for ship collision avoidance is proposed by using an improved swarm optimization algorithm and random linear weighting method. Firstly, the key ship avoidance strategy is employed for analyzing the factors involved in ship collision risk. Then, taking the Convention on the International Regulations for Preventing Collisions at Sea (COLREGs), the risk of ship collision, and voyage loss into consideration, a multi-objective function optimization technique based on a random linear weighting method is proposed to overcome the influence of subjective weight assignment. Finally, an improved black widow optimization algorithm with novel position strategies is employed to determine the optimal course alteration for ship collision avoidance. The feasibility and effectiveness of the proposed ship collision avoidance scheme are demonstrated by the ship's intelligent collision avoidance platform. The proposed collision avoidance scheme may provide a reasonable avoidance angle as a reference for the officer on watch in the practice of navigation.

Water Injection System for Exhaust Gas Cooling of Warships

Khagesh Kumar Choudhary, Dr. P K Sharma, Capt. AVSN Murty, Dr. D Radha Krishna — Mon, 07 Sep 2026 00:00:00 +0100

Warships are increasingly susceptible to detection and engagement by infrared-guided missile systems, necessitating effectivesuppression of exhaust-related thermal signatures. Conventional infrared suppression systems (IRSS) primarily rely on atmospheric air entrainment to reduce exhaust gas temperature; however, advancements in sensor technologies have limited their effectiveness in achieving higher levels of suppression.To overcome this limitation, water injection in the form of fine droplets is introduced into the exhaust stream, enabling enhanced heat extraction through both sensible cooling and latent heat absorption during evaporation.

This study presents an integrated design methodology for a water injection system (WIS) for marine platforms, incorporating nozzle selection criteria, computational fluid dynamics (CFD)-based thermal analysis, and experimental validation. The approach enables systematic optimization of exhaust cooling performance and provides a practical framework for achieving advanced infrared signature suppression.

Effects of Mooring Line Loads on the Stability of Floating Offshore Wind Turbine Structures

Hoi Sang Chan — Mon, 07 Sep 2026 00:00:00 +0100

Consideration of catenary, semi-taut or taut mooring systems in the stability assessments of floating offshore wind turbine structures (FOWTs) required by various rules and regulations of government authorities and classification societies is reviewed. This consideration is categorised into four different levels of mooring line load effects on floating stability from Level 0 as no mooring effect to Level 4 as full mooring effects. Since no commercial ship stability software considers performing stability calculations for a floating body attached to a mooring system, two newly developed stability calculation algorithms are presented to deal with intact and damage stability of FOWTs with catenary/semi-taut/taut mooring systems for stationary or transient design load cases respectively. The results of intact and damage stability analyses for a FOWT in a power production, emergency shutdown and parked conditions show that detrimental effects of mooring system occur at Level 2 or Level 3 with some partial effects, while Level 4 with full effects provides a favourable positive impact.

Exploratory-Level Prediction of the Hydrodynamics of Victorian-Era Steamships

Dr P Loscombe — Mon, 07 Sep 2026 00:00:00 +0100

While computational fluid dynamics or large-scale testing of bespoke models probably offer the most accurate ways of determining the resistance characteristics of historic ships, the long-established semi-empirical method, which dates back to the 1870’s, may still have an important part to play. It could be argued that many aspects of historical ship research are primary concerned with comparative studies rather than establishing absolute values which are the main concern of today’s naval architects. These comparative studies could take the form of testing out a series of “what-if” scenarios which in turn implies a large number of input variables many of which – outside of a few well-documented museum ships – are likely to be far less well-defined than would be acceptable in a modern design office. Large-scale model tests and Computational Fluid Dynamics (CFD) analyses tend to be “resource-hungry”. What can be processed in seconds using spreadsheets or similar level software – albeit at the cost of some loss in accuracy – may take many hours or even days using more advanced methods.

The characteristics of late 19^th Century ships fit reasonably well within available semi-empirical envelopes. This paper attempts to validate two such semi-empirical methods using trial data, published CFD results and model tests for three steamships: HMS Leviathan (1900), HMS Warrior (1860) and the Steamship Great Britain (1843). One Victorian-era sailing ship, the Cutty Sark (1869) and one Georgian-era warship, HMS Victory (1758- ) are also considered as part of this evaluation exercise.

Numerical Investigation of SAVER-BOX for Container Loss Mitigation Under Parametric Rolling on Ultra-Large Container Vessels

J S Park, D Lee, J G Park, Jung Kwan Seo — Mon, 07 Sep 2026 00:00:00 +0100

This study examined the failure behaviour of container securing systems on ULCVs under parametric rolling. Although considerable efforts have been made to mitigate parametric rolling through improved ship design, operational guidance, and classification rules such as Roll Design Assessment, the complete elimination of extreme roll motions cannot always be guaranteed. Complementary structural mitigation strategies are therefore still needed to reduce container loss during such extreme events. An explicit FE model was used to simulate the sequential failure of twistlocks, lashing rods, sockets, and corner castings under a severe roll condition. A mechanical device, the SAVER-Box, was introduced to redistribute inertial loads and delay progressive structural collapse. Container loss was reduced from 93% to 20% when the device was applied. Stress and strain results indicated ductile performance within the assumed rupture limit. A new metric, PCL, was proposed, showing that isolated reinforcement shifted failure locations whereas system-level design improved overall resilience.

An Overview of Emissions Monitoring and Inventory Techniques for Shipping Operations

Marzieh Asadnia Fard Jahromi, Kasra Kafashian, Rouzbeh Abbassi, Fatemeh Salehi — Mon, 07 Sep 2026 00:00:00 +0100

Ship pollution contributes to global anthropogenic emissions, and they have a significant impact on human health as
well as climate change. Thus, this paper aims to review recent studies that used various methodologies to measure and estimate ship emissions. It provides a comprehensive review of different techniques for monitoring ship emissions, including measurement and estimation methods, to identify each technique’s features, strengths and limitations. Three main methodologies for ship emission measurement are investigated, including the on-board measurement, the in-situ measurement for sniffer method, and optical remote-sensing techniques such as Differential Optical Absorption Spectroscopy (DOAS), Light Detection and Ranging (LiDAR), and UV-CAM-based monitoring. Direct measurements are not always possible due to time and human resource restrictions, and the difficulty of installing measurement devices. Therefore, emission inventories are the most commonly applied method to estimate ship emissions. Estimation methods, including inventory approaches and the application of machine learning techniques, are also reviewed here. Among the reviewed approaches, direct measurements provide high accuracy but may be costly and operationally challenging, whereas inventory and data-driven methods offer broader applicability for large-scale assessments. Future work should focus on integrating measurement, inventory, and machine-learning approaches to improve reliability, scalability, and standardization in ship-emission monitoring.