VESSEL REVIEW | Silver Raven – Woods Tours welcomes electric catamaran to River Thames sightseeing fleet
UK-based family-owned tour company Woods Tours has taken delivery of a new sightseeing vessel for operation in the River Thames in London.
The all-electric Silver Raven will be deployed on Woods Tours’ new Tower of London river tour service. Design work on the 39- by 10-metre (130- by 32-foot) vessel was provided by One2Three Naval Architects of Australia while construction took place at Pendennis Shipyard in Cornwall.
The design work complied with Lloyd’s Register and UK Maritime and Coastguard Agency requirements.
“Silver Raven will be the UK’s first fully electric sightseeing vessel, carrying 250 passengers for a 40-minute loop tour of the River Thames,” One2Three told Baird Maritime. “She has a minimalistic aesthetic and contemporary design, boasting large glass windows on her roof and sides to offer panoramic views of the London skyline.”
Electric propulsion configured for heavy-duty daily use
The designer said the client required a catamaran vessel capable of carrying 250 passengers for a tourist loop of the main sights on the Thames, and also to be used for charters of up to 299 passengers.
The design needed to be high quality and reliable, in order to keep a regular timetable of up to eight return cruises a day and be zero-emissions capable, especially once the shoreside infrastructure is completed.
“The vessel’s design was required to be clean and contemporary, whilst still echoing the prime of Thames cruising and showing design influence from the 1920s and the 1930s,” said One2Three.
The newbuild boasts lightweight aluminium construction and a draught of only 1.5 metres (4.9 feet). The indoor and outdoor seating areas offer a total of 316 seats.
The vessel features General Energies Electric Ship’s general control system that ensures quiet operation. This includes two Danfoss 165kW liquid-cooled electric motors, two 360kWh EST-Floattech batteries, two 125kW generators for extending the vessel's range as well as for emergency use, two 50kVA transformers, AC and DC fast charging systems, an energy management system, and a propulsion control system.
The Danfoss motors drive a five-bladed, fixed-pitch propeller (FPP) via a DMT1110A gearbox. The propeller’s diameter of 955 mm provides the lateral manoeuvrability necessary for navigating the busier portions of the Thames.
“The hybrid electric motor driving the FPP propulsion system is entirely new,” One2Three told Baird Maritime. “Two twisted flow rudders steer the vessel, and should lead to reduced cavitation and erosion risk over time.”
The electrical integration was completed by Vulkan UK. The vessel has a central main deck switchboard room, which contains the electrical control panels and switchboards. The batteries are located down in the hull to maximise the deck space for passengers and keep the vessel’s centre of gravity as low as possible.
“The amount of cabling for an electric vessel is substantial,” the designer remarked. “This had to be kept to a minimum where possible to not have a detrimental effect on vessel performance. The space underneath the deck between the hulls was utilised for cable runs between the e-motor room, main deck switchboard and hull batteries in order to keep the weight centred as low as possible and out of the passenger space.”
Ensuring luxurious spaces without impacting overall displacement
Twelve mooring bollards will facilitate easy docking and secure the vessel for ease of passenger embarkation and disembarkation. The exterior forward deck is cambered to assist drainage in the event of heavy rain and prevent water pooling on deck, thus allowing for operation even in inclement weather. The interior deck is flat for ease of attaching seat tracks and fitout equipment.
The onboard facilities include a saloon bar that also serves alcoholic drinks. Also inside are a bespoke wool carpet, leather seating, and wheelchair-accessible spaces.
The interior styling work was done by Kate Woods, Design and Development Director at Woods Tours’ luxury river cruise division Woods’ Silver Fleet.
“The biggest design challenge was minimising weight whilst maintaining the luxury fitout and passenger experience,” said One2Three. “Weight increases lead to a larger battery capacity required to run the operational 10-knot speed as well as exceeds the route’s shallow draught restrictions.
“Shoreside charging capabilities in London were not known at the start of the design, and so the decision was made to install two generators to provide the power required to charge the batteries for a full day of tours. Wash sensitivity is a focal point so the hull was optimised in length to ensure the vessel’s wash is significantly less so as not to affect the local environment.”
The amount and size of equipment required for the battery control system evolved throughout the design, which all needed to be separated from the passenger space. The weight was substantial and so it was positioned as close to the centre of the vessel as possible.
“The range of loading conditions is large due to passengers having a broad variety of areas to sit (from the aft bar to the expansive forward exterior deck),” One2Three told Baird Maritime. “These trim conditions all needed to be designed within the capability of the vessel.”
The designer said the client was involved and focused on the aesthetic design in order to ensure that the vessel was novel but also tied into their existing fleet. Regular meetings were held to ensure collaboration and to find the best outcome for the vessel whilst not losing sight of the requirement to be lightweight.
“This design was the first time working with Vulkan UK as the electrical integrator, so new communication lines and understanding of processes had to be established. Many lessons were also learned with regard to the electrical propulsion system and battery integration.”
Can accommodate multiple tour loops in one day
Silver Raven will be operated daily year-round by Woods’ Silver Fleet in partnership with Historic Royal Palaces. The vessel’s regular route will bring her to a number of famed London attractions including Southwark Cathedral, St Paul’s Cathedral, the London Eye, Tower Bridge, and HMS Belfast.
The vessel will run up to eight daily tourist loop tours of the main sights on the Thames even during periods of inclement weather. A single return loop will take approximately 45 minutes at a speed of 10 knots.
“The vessel will reduce the current energy costs for the owners compared to their traditional diesel vessels, and will allow them to carry more passengers per day,” said One2Three. “It will also reduce vessel emissions to close to zero once the charging infrastructure is installed.”
