Alicat Workboats Delivers Thames Spirit Catamaran for London Spill Response

Thames Spirit, the Port of London Authority's new oil-spill response and dive-support catamaran, was built by Great Yarmouth specialist Alicat Workboats around a brief that asked for contradictory things simultaneously: get there fast, then work in barely a metre of water.

Chartwell Marine handled the naval architecture, centering the design on twin Scania DI13 engines driving Kongsberg Maritime S36 waterjets. That combination gives Thames Spirit a cruising speed of 20 knots and a sprint capability of 24 knots, which matters because rapid arrival is the first requirement of any effective spill-response operation. The waterjet drives also allow maneuvering in water as shallow as one metre, eliminating the shaft and rudder exposure that would ground a conventionally propelled vessel in the same estuarine conditions.

The 17.0 m × 6.7 m hull is built around a 16 m² moonpool integrated with a pump recovery system for spill operations. Centralizing that machinery within the hull rather than at the deck edge keeps it away from tidal current and shares the structural provision with the dive-support role. IMO Tier III machinery underpins both functions, and the vessel is fully compatible with HVO and other low-carbon fuel alternatives.

Thames Spirit will be operated by the PLA from Gravesend, covering the tidal Thames from the densely populated inner stretches through to the outer estuary. That operational geography shaped every tradeoff in the brief. Chartwell Marine's Andy Page and Alicat Director Simon Coote both prioritized compact footprint alongside payload capacity for specialist spill-response equipment and shallow-water clearance, three requirements that can quickly pull a design in incompatible directions on a workboat this size.

Beyond spill response and dive work, Thames Spirit is available for general environmental protection and support tasks, which gives the PLA flexibility across a river where operational demands do not wait for ideal conditions. For other European port authorities working through the same shallow-water response calculation, the vessel now exists as a built, tested, and delivered answer rather than a theoretical specification.