The SPAN project has achieved all the objectives. It provides a sound basis for planning safe passage at high speed in shallow water and a real time aid for navigation for fast twin hulled vessels. Software tools have been developed to optimise waterjet design, based upon new proven data, providing great improvements in shallow water. A computer model has been developed through which operational limits in shallow water could be realistically examined to ensure safe passage. An onboard model-based predictive system for collision/grounding avoidance in shallow waters has also been developed, to maintain "safe navigation."
A new more efficient and low wash hullform has been developed. An ultra low wash hullform has also been designed for use when wash is the very most important factor.
A new design for waterjets will result in lower weights of the craft and improved manoeuvrability. The excellent CFD results in comparision with the full scale trials have provided the consortium with a strong tool to further optimise the inlets for shallow water effects.
The navigational aid developed under the SPAN project exceeds the original objectives of the project proposal. As far as the consortium is aware there is nothing remotely as sophisticated available outside the military aerospace industry.
Objectives and content
The market for fast ferries in deep water is well established. SPAN will extend this market by developing fast passenger ferries capable of operating in restricted and shallow waterways. In areas of high population density surrounding estuarine or wide river systems fast ferries provide an alternative to road transport giving economic and environmental benefits, by giving people better access to work and reducing road traffic congestion with associated fume emissions. For example, the Transtejo ferry service run in Portugal has a carrying capacity of 100,000 to 150,000 commuters per day. Much of the passage running is in shallow waters where excessive wash is also a problem.
It is known that vessel performance in shallow waters is different to that in deep water. Single hull vessel characteristics have been well researched but verified reliable data has not been developed to a sufficient extent for twin hulled water jet propelled ferries which now offer superior performance. Therefore, increased use of high speed twin hulled vessels in these conditions is handicapped by the absence of independent verified hydrodynamic data to predict their behaviour, particularly in shallow waters.
Once this data becomes available, enhanced controls can be developed to provide safe manoeuvring in busy waterways.
Without unreasonably impeding the use of this beneficial form of transport, Regulatory Authorities have a serious problem in interpreting IMO Code of Practice for High Speed Craft, in the absence of sound data upon which to base their licensing decisions.
The objective of SPAN is to provide a sound-basis for planning the safe passage at high speed in shallow water and to provide a real time aid for navigation for fast twin hulled vessels by :
- Providing software tools to optimize design, based upon new proven data, enabling shallow water jet performance to be within 48% of deep water, compared with the present 10-20%.
- Creating a computer model by which operational limits in shallow water can be realistically examined to ensure "safe passage."
- Building an on board model-based predictive system for collision/grounding avoidance in shallow waters, to maintain "safe navigation."
SPAN will provide safe passage for ferries in the range of 150 - 180 tonnes laden displacement carrying 350 - 500 passengers running at 25-30 knots in only 2 - 5m of water at drafts of 1.2 - 1.5m restricting wash to 30 cm. To achieve these results, the work will develop 5 main sets of deliverables in the following areas :
- hull design, including CFD (computational fluid dynamics) modelling, water tank testing and sea trials.
- water jet design, taking into account the effects of water intake interaction with the hull
- an intelligent software system encoding the results of the modelling in the form of guidelines on safe operating criteria, implemented using a combination of Al and conventional techniques. Particular attention will be given to "squat" behaviour, the effects of wave action and safe manoeuvrability - wash limits, environmental and safety considerations on permissible wash height.
- aids to navigation which will integrate the safe operating criteria with conventional navigational instruments (e.g. radar) to provide a pilot advisor.
SPAN is an end-user driven project. The demand for the results of the project comes from Transtejo Transportes Tejo (PT), which operates a ferry service across the Tagus river in Lisbon. The industrial partners seeking to meet these needs are FBM Marine (GB) a shipbuilder which already designs and builds high-speed, twin hulled passenger ferries, and LIPS (NL) which manufactures marine propulsion and control systems. These industrial companies are assisted in the project by British Maritime Technology (GB) with extensive experience of physical hydrodynamic modelling, and of adding intelligence to industrial software, the Unit for Marine Technology and Engineering of the Instituto Superior Tecnico (PT) in Lisbon and CETENA (IT) which is a subsidiary of Fincantieri, Italy's principal shipbuilder, and which is principally interested in developing three dimensional CFD techniques needed for SPAN.
Funding SchemeCSC - Cost-sharing contracts
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