One of a pair of simple but safe, attractive and economical aluminium electric catamaran ferries for inland waterways in the Netherlands, Altena VI is proudly innovative in many respects.
The 35-metre, shallow draught vessels are endlessly manoeuvrable and can be operated by one person. They are designed to comfortably and safely carry 100 passengers, each accompanied by a bicycle.
"Other shipyards and consultants had advised shipowner Riveer that it was not possible to satisfy the requirement for emission-free operation and that LNG propulsion was more viable than all-electric propulsion," CoCo Yachts told Baird Maritime. "However, after thorough research, we showed that fully-electric sailings were possible with the aid of batteries. There are no diesel generators or diesel heaters whatsoever on the ferries; the power from the batteries would suffice for both the main propulsion and the auxiliaries."
CoCo Yachts conducted studies on the optimum hull design using CFD software. For Altena VI, the company also had to consider shallow waters. The outcome during river speed trials validated the design team's calculations, thus proving that CFD tools are effective when used properly.
"We also needed to convince the owner that the optimum length of each ferry was at least 35 metres to achieve the best efficiency when sailing at the required service speed in shallow waters," the designer said. "The ferries are reasonably long for only 100 passengers and 100 bicycles, but making the vessels shorter would increase their energy consumption as well as their cost."
Commenting on present trends in naval architecture, CoCo Yachts said hybrid and electric propulsion systems are becoming popular for use by medium-speed ferries. However, shipowners must realise that travel schedules may need to be adjusted to allow for battery charging or swapping, and that a few minutes' difference can lead to savings on investment as well as lower life-time costs.
"Classification societies, and especially flag states and European rules, need to adapt in order to accommodate the latest products and solutions," the designer told Baird Maritime. "This is because in some cases, the rules don't fit the product."
CoCo Yachts had a busy year in 2023, thanks to a number of fast ferry and tourism newbuilding orders from the Far East. Some projects are even scheduled for completion in the middle of 2024, and the company is considering hiring additional staff in anticipation of this.
"The trends for the coming years will be emission-free propulsion systems for slow- and medium-speed ferries. The challenge therefore is in setting the ideal price for those products, which are otherwise rather costly due to the complexities associated with electrical installation work. We believe that as soon as these technologies can be made simpler and more cost-effective, diesel engines will be phased out earlier."
The designer clarified that being emission-free also covers noise. Electric ferries produce less noise, which makes them ideal for passengers, crew, and the environment.
"The Dutch workboat industry meanwhile needs to catch up with new production methods," CoCo Yachts told Baird Maritime. "Aluminium, carbon fibre, and other lightweight materials need to become standard for ferries, even for low-speed vessels. Maintaining weight is important, and steel is not the right material to use."
The designer added that aluminium has advantages with regard to energy consumption. When local Dutch industry can make this kind of product at competitive prices, it will become a preferred option over steel.
"This also applies for all materials used on board vessels. The industry should be focused on saving weight, and in most cases, this will help reduce overall cost."
