Cat over shallow water

A high-speed catamaran capable of travelling over shallow water could be used to transport cargo on Europe’s rivers, reducing road congestion, its UK developers claim.

The vessel consists of the twin rigid side hulls of a catamaran, with a pressurised cushion of air in between. The air cushion is generated by a system of lift fans, and is contained by the side hulls and seals at the front and rear of the vessel.

The PACSCAT (Partial Air Cushion Supported Catamaran) is being developed by a European consortium, led by the University of Southampton, with project management by UK-based Marinetech South and technical co-ordination by Independent Maritime Assessment Associates (IMAA).

The catamaran will have a capacity of around 2,000 tonnes – the equivalent of 45 truck loads – and will be able to travel at around 25 miles an hour, around twice the speed of conventional freight barges, said Dr Jonathan Williams, project co-ordinator at Marinetech South.’Fuel costs will be higher than a conventional barge, but these should be offset by the increased freight capacity of operating at higher speed,’ he said.

Unlike conventional barges, the catamaran will be able to travel over sections of very shallow water, meaning it will continue operating in summer when water levels are low. This will be made possible by built-in over-capacity within the lift fan system of the diesel-powered vessel. So by simply opening up the throttle the fan pressure can be increased, allowing the catamaran to ride over the shallow stretches of river, before going back to normal operation once it is in deeper water again.

‘In summer you can get very much reduced water levels. In a conventional barge, if the water drops below a certain level you simply can’t operate the service. Clearly if you’re trying to run a regular and reliable service to meet just-in-time logistics requirements, that is pretty unacceptable,’ said Williams.

The project is being funded with a grant of almost e1m from the EU’s Framework Programme. The team has already completed most of the modelling work, and is now involved in the detailed design phase, which is due to end next May. Williams said the concept is now ‘shaping up attractively’.

The project partners hope the vessel will be a realistic alternative to road transport for those who do not want their goods stuck in traffic jams on Europe’s congested roads. ‘If you have got high-value goods, and what you want is a highly reliable long-distance transit mode, then PACSCATs may well be ideal, because they will be operating to a timetable and will have high immunity from weather upsets and congestion,’ he said.

The project is focusing initially on transport along the Rhine and Danube, but the team hopes to extend its use to a number of other waterways. ‘We have identified some routes on the Rhine and Danube where you could offer a service that is twice as frequent as existing services, for the same number of vessels, simply because you can get from one end of the route to the other in half the time,’ said Williams.

The UK does not have the size of inland waterways or inland ports of other European countries, so it will not be an initial target for the consortium. But outside the remit of the EU-funded project the team is also investigating the possibility of creating PACSCAT variants for use in short sea shipping, and has already done some initial work to ‘rough’ out the design.

Hybrid catamaran air cushion vessels have also been considered as cargo carriers for both the UK and US navies.

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