Safe and smooth through a shallow fairway

Since the ever growing dimensions of all vessel types coming to the Flemish harbours which started in the mid 80’s of last century, the research at Flanders Hydraulics Research, a laboratory belonging to the Flemish Government, concerning harbour infrastructure and fairways was shifting from structural based examinations to ship related examinations. The key question was and is: how can an existing or new-built ship access the shallow water areas in Belgium safely and smoothly? With the installation of the first ship manoeuvring simulator in 1989 and the Towing Tank for Manoeuvres in Shallow water (co-operation Flanders Hydraulics Research- Ghent University) in 1992 fundamental and applied research studies followed successively. In May 2008 this joint work resulted in the Knowledge Centre Manoeuvring in Shallow and Confined Water (www.shallowwater.be) established to fix, extend and provide the scientific know-how on the behaviour of vessels in shallow and confined navigation areas. The presentation will give an overview of the latest fundamental researches executed at FHR and UGent concerning the influence of shallow water manoeuvring, bank effects and ship-ship interaction. Based on model tests with scale models of about 4 m length forces have been measured and the influence of different test parameters have been examined. Combining these measurements with mathematical models incorporated in the simulators gives the opportunity to evaluate new situations together with the pilots of the Flemish Pilotage. This research has been used to evaluate the accessibility of the largest containerships (the E-type vessel of Maersk Sealand and the 366 m vessels of other shipping companies as MSC and CMA-CGM) to the port of Antwerp and the port of Zeebrugge and the largest LNG carriers to the LNG terminal in Zeebrugge. New limits have been examined for the West lock in Terneuzen for Kamsarmax vessels where the useful width of 38 m for the lock is compared with the vessel’s beam of 37 m. This high blockage introduces lock effects that determines the behaviour entering the lock

Estuary traffic: an alternative hinterland connection for coastal ports

In 2007, the Belgian Federal Authorities issued a Royal Decree concerning "inland vessels that can also be utilised for non-international sea voyages", allowing inland vessels to operate in coastal areas between the Belgian coastal harbours and the Belgian inland waterway network via the Western Scheldt, provided that – among other requirements – a risk analysis demonstrates that the probability of adverse events such as bottom slamming, overtaking of water on deck and ingress of water in open cargo holds is limited to an acceptable level. Several tankers and container vessels are nowadays operating in significant wave heights up to 1.90 m. The present paper intends to provide background into the present regulations, to describe the methodology used for performing risk analyses, and give an overview of the present and future research at Flanders Hydraulics Research and Ghent University on estuary container vessels

Synergy between theory and practice for ultra large container ships

In 2003 an accessibility study based on real-time simulations for the S-class container ships of Maersk Sealand was performed at Flanders Hydraulics Research in cooperation with all involved parties (public and port authorities, pilots, tug and shipping company). The regulation for the upstream and downstream navigation on the Western Scheldt did not accept the arrival of a ship with length over all greater than 340 m. The paper describes two main research studies executed to fill in the gap of knowledge about the manoeuvring behaviour of container ships in shallow and confined water: the accessibility of Ultra Large Container Ships with a maximum capacity of 14,000 TEU to the Western Scheldt and the accessibility of the Berendrecht Lock and Delwaide Dock located on the right bank of the port of Antwerp. An integrated simulation platform with mathematical models describing hydrodynamic (manoeuvrability, ship-bank and ship-ship interaction) and external (wind, current, tug assistance) forces and coupled ship manoeuvring simulators helped in evaluating the possibilities and limitations of head-on encounters, lock and turning manoeuvres. The combination of research and training has finally led to the arrival of the MSC Beatrice in April 2009. After a validation period of more than half a year, characterised by a constant adaptation of negotiated restrictions, a new regulation for the upstream and downstream navigation is being prepared

Where and when to inject low molecular weight heparin in hemodiafiltration? : a cross over randomised trial

Background and Objective : Low molecular weight heparins (LMWHs) are small enough to pass large pore dialysis membranes. Removal of LMWH if injected before the start of the session is possible during high-flux dialysis and hemodiafiltration. The aim of this study was to determine the optimal mode (place and time) of tinzaparin administration during postdilution hemodiafiltration. Study Design, Setting, Patients : In 13 chronic hemodiafiltration patients, 3 approaches of injection were compared in a randomised cross over trial: i) before the start of the session at the inlet blood line filled with rinsing solution (IN0), ii) 5 min after the start at the inlet line filled with blood (IN5) and iii) before the start of the session at the outlet blood line (OUT0). Anti-Xa activity, thrombin generation, visual clotting score and reduction ratios of urea and beta2microglobulin were measured. Results : Anti-Xa activity was lower with IN0 compared with IN5 and OUT0, and also more thrombin generation was observed with IN0. No differences were observed in visual clotting scores and no clinically relevant differences were observed in solute reduction ratio. An anti-Xa of 0.3 IU/mL was discriminative for thrombin generation. Anti-Xa levels below 0.3 IU/mL at the end of the session were associated with worse clotting scores and lower reduction ratio of urea and beta2microglobulin. Conclusions : Injection of tinzaparin at the inlet line before the start of postdilution hemodiafiltration is associated with loss of anticoagulant activity and can therefore not be recommended. Additionally, we found that an anti-Xa above 0.3 IU/mL at the end of the session is associated with less clotting and higher dialysis adequacy