Figure - available via license: Creative Commons Attribution 4.0 International
Content may be subject to copyright.
Relationship between the length of a ship and the shortest stopping distance for a fully loaded VLCC under sail at 12 knots.
Source publication
Recently, the importance of safety-monitoring systems was highlighted by the unprecedented collision between a ship and a jetty in Yeosu. Accordingly, in this study, we introduce the concept of risk based area and develop a methodology for a jetty safety-monitoring system. By calculating the risk based areas for a ship and a jetty, the risk of coll...
Context in source publication
Context 1
... Knight's equation calculates the distance through a test of the shortest stopping distance of the ship, Akira's equation-which can calculate the shortest stopping distance using the current velocity-was used in this study. Table 1 shows an example of the shortest stopping distance when a fully loaded very large crude carrier (VLCC) went full astern during navigation at a normal harbor speed of 12 knots. The shortest stopping distance is calculated using Akira's equation. ...Citations
... The ship's stopping ability as measured by the crash stop manoeuvre can be used to prevent collisions [7]. Nam [8] used the shortest stopping distance during the crash stop manoeuvre to calculate the riskbased area. However, the approach used by Nam still uses a simple estimate. ...
Ship collisions often occur alongside the traffic lanes. In some cases, the main issue is related to the ship's stopping ability. This study performs evaluation of ship stopping ability using computer simulation program developed in Matlab Simulink platfotm employing Dynamic Thrust Generation Model (DTGM). The propeller thrust and torque coefficient exerted in the DTGM algorithm were obtained using computational fluid dynamics (CFD) method. Accuracy of the coefficients checked via triangulation method against the standard polynomial-based data and result of model test indicates a relatively small error. The simulated crash stopping manoeuvre using the coefficients comply the IMO Manoeuvring Standards criteria and has a good agreement to model test-based result.
... The ship's stopping ability as measured by the crash stop manoeuvre can be used to prevent collisions [7]. Nam [8] used the shortest stopping distance during the crash stop manoeuvre to calculate the riskbased area. However, the approach used by Nam still uses a simple estimate. ...
Ship collisions often occur alongside the traffic lanes. In some cases, the main issue is related to the ship's stopping ability. This study performs evaluation of ship stopping ability using computer simulation program developed in Matlab Simulink platfotm employing Dynamic Thrust Generation Model (DTGM). The propeller thrust and torque coefficient exerted in the DTGM algorithm were obtained using computational fluid dynamics (CFD) method. Accuracy of the coefficients checked via triangulation method against the standard polynomial-based data and result of model test indicates a relatively small error. The simulated crash stopping manoeuvre using the coefficients comply the IMO Manoeuvring Standards criteria and has a good agreement to model test-based result.
... spring mass system. However, case histories (Chenna et al., 2017, Goulburn-Murray Water, 2012, Nam, 2015, Ramancharla, 2014 suggests that, adverse climatic conditions, such as: cyclones or tidal variations may bring significant damages on jetties and its nearby structures due to the unspecified lateral impacts from the sea wave actions. This makes the jetties vulnerable to further applied lateral loads due to the ship impacts. ...
The current study presents a detailed assessment of an existing jetty in the Chittagong Dockyard through the 'non-destructive' and 'visual-inspection' method. The damaged structural elements were classified into four different grades namely very severe, severe, moderate and acceptable (i.e. Grade A to Grade D). It was observed that the damaged structural elements were mainly the girders, secondary beams, fender piles and springs. 51% of girders and 44% of secondary beams were severely damaged. The most probable causes of the damage of different structural elements were mainly due to inadequate clear cover and harsh environment resulted in corrosion of reinforcement. However, the main piles, floor beams (pre-cast unit) and deck slab were in better condition in comparison with the girders and secondary beams. The findings of this study will facilitate the authority to take quick decisions on repairing, retrofitting or replacement of the damaged structural elements based on its level of severity.
... In other words, how to identify them effectively becomes an important issue related to safety. Meanwhile, ship crews and vessel traffic service (VTS) supervisors also have to identify banks, shoals, rocks and channel structures in order for them to avoid possible grounding and collision incidents with harbour facilities (Mazaheri et al., 2012;Nam et al., 2015). ...
This research proposes a Bayesian Network-based methodology to extract moving vessels from a plethora of blips captured in frame-by-frame radar images. First of all, the inter-frame differences or graph characteristics of blips, such as velocity, direction, and shape, are quantified and selected as nodes to construct a Directed Acyclic Graph (DAG), which is used for reasoning the probability of a blip being a moving vessel. Particularly, an unequal-distance discretisation method is proposed to reduce the intervals of a blip's characteristics for avoiding the combinatorial explosion problem. Then, the undetermined DAG structure and parameters are learned from manually verified data samples. Finally, based on the probabilities reasoned by the DAG, judgments on blips being moving vessels are determined by an appropriate threshold on a Receiver Operating Characteristic (ROC) curve. The unique strength of the proposed methodology includes laying the foundation of targets extraction on original radar images and verified records without making any unrealistic assumptions on objects' states. A real case study has been conducted to validate the effectiveness and accuracy of the proposed methodology.
