In today’s economic climate, ports need to maximise their efficiency while ensuring safety of passage. As vessels increase in size, the dilemma facing many ports is that their existing static underkeel clearance (UKC) rules are inflexible, thus deeper vessels cannot transit without compromising safety. As static rules do not change with the environmental conditions, the actual clearance and the potential of vessel grounding varies on any given day; for this reason static rules need to be conservative. In contrast, dynamic UKC systems, calculate the required UKC depending on the prevailing environmental and vessel conditions; this ensures every transit satisfies appropriate risk standards.

With safety assured, economic and efficiency benefits are realised when conditions allow deeper draughts and/or extended tidal windows. This dynamic information can now be relayed to the pilot, via a chart overlay, to provide real-time 3D displays of the safe navigational areas, thereby ensuring continued safety of navigation.

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The Columbia River Bar (USA) is one of the most dangerous and challenging navigated stretches of water in the world. However, successful passage grants access to several inland ports and waterways through which transportation between the US Pacific Northwest and the world averages 40 million tons of cargo valued at $20 billion each year. During 2011 and 2012 OMC International performed under-keel clearance (UKC) modelling and detailed validation studies for the Columbia River Bar Pilots including measurement and analysis of the motion of 24 vessels crossing the Columbia River Bar in moderate to high seas. Measurements and detailed UKC modelling reveal that UKC needs to be carefully managed on the Columbia River Bar. Conditions under which touch bottom events might occur vary greatly with vessel class and transit direction such that no clear “rules of thumb” can be established to ensure risky transits are avoided. A web-based demonstration DUKC® system has since been established and this has been used by the Columbia River Bar Pilots to predict and/or analyse the UKC of more than 130 deep-draft transits.

Click here to read the full article: https://wpstaging.omcinternational.com/wp-content/uploads/2010/06/Coasts-Ports-2013-Under-keel-Clearance-at-the-Columbia-River-Bar.pdf

Dynamic Under Keel Clearance (DUKC®) is a proprietary under keel clearance (UKC) management system (installed at 19 ports world wide) that predicts the UKC of vessels, accounting for the latest environmental, vessel and transit information. Historically, DUKC® Systems have been recognised for the enormous economic benefits which are usually provided to waterway owners and users. However, increasing international recognition is being given to the significant benefits which dynamic determination of under keel clearance provides as a risk mitigation tool. While OMC has pioneered this tool for 17 years, leading international bodies such as PIANC and IALA are now developing guidelines and standards around dynamic UKC determination.

Risk mitigation has been the primary motivation for the recent DUKC® implementation into the Port of Melbourne, Australasia’s largest and one of the world’s top 50 container ports. The entrance to the Port is considered one of the most difficult pilotage and technical modelling challenges anywhere on earth. To manage these conditions, DUKC® technology has been integrated onto Portable Pilot Units (PPU)s and into the VTS Centre to enable vessel speed and predicted under keel clearance to be monitored onboard and ashore. While primarily a risk mitigation tool in the Port’s challenging waters, the full DUKC® suite has been installed to also deliver efficiency benefits to port users.

This implementation process of DUKC® at the Port of Melbourne involved PoMC installing the latest state of the art instruments to provide near real-time environmental data of the highest quality. Intensive modelling studies were undertaken of wave/current interaction effects on vessel motions, including full-scale vessel motion measurements, in order to validate DUKC® predictions for use in this challenging stretch of water. In addition, PoMC commissioned two independent risk assessment studies.

This presentation summarises 3 key pre-implementation studies undertaken by the Port of Melbourne which concluded that the DUKC® system was capable of delivering improved safety and efficiency benefits to port users in comparison to existing static rules. It also details OMC’s experience in installing real time In-Transit DUKC® for the Port of Melbourne, with the main challenge being the reliable delivery of data from ship to shore. The presentation concludes with a brief introduction to DUKC Series V, the most recent adaptation, which is web-based.

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OMC International is the sole provider of Dynamic Underkeel Clearance (DUKC®) systems. OMC’s systems predict and manage underkeel clearance for vessels travelling along depth restricted waterways. These systems have now advanced to a level where users, such as pilots and VTS officers, can monitor the vessel progress and underkeel clearance (UKC) in real-time and assess how changes in vessel speed can optimise vessel squat and trim. This paper describes the how squat predictions are used in operational conditions and how realtime speed control is used to optimise vessel squat and trim for underkeel clearance purposes. Three case studies of operational systems are presented.

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Port Adelaide channel is affected by tidal streams. Therefore, Flinders Ports currently imposes sailing restrictions while the tide is rising or falling faster than a specified threshold due to concerns about reduced manoeuvrability at these times. A manoeuvrability study, with a specific focus on bank effects on large PostPanamax container vessels, was undertaken in order to confirm the suitability of sailing restrictions based on tide rate of change, and to determine other factors that contribute to bank effects and thus reduced manoeuvrability. Two complimentary investigative approaches were used.

The first approach was an analysis of vessel tracks for 6 months of supplied AIS data. Situations where vessels approached the channel boundaries were investigated for correlation to environmental conditions, such as tidal streams and wind forces, and other conditions such as under-keel clearance (UKC) and vessel speed. The results of this analysis found that tide rate of change showed no correlation with vessels approaching the channel boundaries. A correlation was observed between increased vessel speed and a higher chance of approaching the channel boundaries.

The second approach was a desktop simulator study, to identify which transit factors induce a higher risk of approaching the channel boundaries. For this study, a design vessel was designated by Flinders Ports as a Post-Panamax container vessel with 300m LOA, 40m beam, and 13m static draft. While a vessel maintains a centreline track, bank effects tend to balance out. However, once a vessel deviates from this track, the various factors contributing to bank effects can very quickly have a large impact on vessel manoeuvrability. The approach of combining theoretical simulation with actual measured vessel behaviour proved a useful method to investigate the underlying factors influencing vessel behaviour at Port Adelaide.

Click here to read the full article: https://wpstaging.omcinternational.com/wp-content/uploads/2019/09/Coasts-Ports-2019-An-investigation-of-bank-effects-by-means-of-vessel-track-analysis.pdf