VESSEL REVIEW | Electric-powered buoy maintenance craft for Scotland’s Loch Lomond National Park

Liverpool-based boat builder Water Witch has delivered a new catamaran workboat to the Loch Lomond National Park Authority for maintenance and other support roles in the waters of Loch Lomond near Glasgow in Scotland.

The workboat has an LOA of eight metres, a beam of 2.58 metres including the fendering, and a displacement of 1.4 tonnes. The custom-built craft is powered entirely by electricity and is being used primarily for the maintenance of hazard buoys across the loch. The choice of electrical power for the vessel’s propulsion is in line with current park policy requiring vessels to generate reduced emissions while operating within the fragile waters.

The workboat is fitted with a large work deck capable of accommodating 1.5 tonnes of assorted cargo, perimeter guardrails with storage hooks/clips, a recessed storage under deck, an electric windlass, and a lifting frame for handling buoys using a pontoon configuration to provide a spacious and well functioning work platform. A shallow draught means that the craft can operate in areas of Loch Lomond that cannot be accessed by larger vessels.

A customised road trailer was also supplied to allow the vessel to be easily deployed to different sites, and the A-frame is removable to ensure ease of transportation.

The vessel’s hull is made from 100 per cent recyclable aluminium. A modified bow section guarantees improved performance while underway and for buoy lifting. Five separate watertight compartments provide improved stability. The wheelhouse, which is also made of aluminium, offers excellent all-round visibility with safety glass windows set in rubber.

Power is provided by a Torqeedo setup that includes four lithium batteries and a 12kW electric outboard. The vessel’s electric controls feature a built-in GPS, an on-board computer and display for information such as speed and input power, state of charge and remaining range, and even an advanced communication system that links users’ Bluetooth and App technology to the complete system. Charging of the batteries is done with the aid of a shore power cable and can be completed within 10 hours. The batteries also have integrated protection to prevent overcharging.

The electric outboard can propel the craft to a speed of seven knots, and to do so with significantly reduced noise compared to the diesel engines installed on the park’s earlier maintenance boats. Also, tests showed that a single full charge of the batteries can enable the craft to sail for up to 32 kilometres.

Even with its compact size, the workboat is highly versatile, being equipped to handle a variety of tasks besides the maintenance of buoys. These include the towing of vessels, personnel transport, rescue missions, and oil spill response. This multi-functional capability translates into a significantly reduced need for greater numbers of single-use-only vessels. Maintenance and other support activities can therefore still be effectively performed throughout the loch by fewer vessels, and this means noise and pollution in the famed national park – which is visited by about four million people each year – being reduced even further.

Click here for the latest news, vessel reviews, and features for this month’s Naval Architecture Week.