VESSEL REVIEW | Trym – Compact suction dredger ensures navigation safety at UK's Bristol Port

The Bristol Port Company (BPC) in the UK has taken delivery of a new cutter suction dredger (CSD).

Purpose-built to meet the unique dredging needs of the Port of Bristol, the 34-metre (110-foot) Trym has already begun maintaining safe navigation depths in the docks, ensuring that the port remains open and accessible for trade.

The acquisition of the new dredger is in line with BPC’s expansion plans, which include the development of an offshore floating wind terminal targeted for full operation by 2030.

Equipped with a rotating cutter head, the CSD is highly efficient at breaking through seabed mud, churning it up, and redistributing it back into the estuary. According to BPC, she is capable of moving over a million cubic metres (35 million cubic feet) of mud from the docks.

The vessel's swing arm configuration enables precise, high-torque cutting through dense seabed sediment, particularly the silty mud prevalent in the Bristol Channel.

Laid out for greater operational flexibility

The design is ideal for operation in confined dock areas, where manoeuvrability is essential. By allowing the cutter head to be articulated independent of the main hull, this approach reduces the need for vessel repositioning during operations.

The optimised cutter ladder and spud system have been engineered for the tidal variations and soft soils of the Severn Estuary.

The rotating cutter head is powered by a high-capacity hydraulic drive, allowing it to churn up material efficiently, while reinforced dredging hoses handle high-volume sediment transport without excessive wear.

Trym operates with a hybrid propulsion system consisting of engines that run on biofuel, a lower-emission alternative to traditional diesel. Additionally, she utilises environmentally friendly hydraulic oils.

The design has also been made to allow for future low-emission technologies to be incorporated and upgraded to continuously improve the vessel’s systems and support the Port of Bristol’s environmental goals. For instance, modular engine bays were incorporated into the design from the outset in order to facilitate retrofits for battery storage.

Built for year-round operation in port waters

Trym is being operated within the Port of Bristol’s 30 kilometres (19 miles) of maintained waterways, including the Royal Portbury and Avonmouth docks. These areas handle over 15 million tonnes of cargo annually, necessitating year-round dredging to counter siltation from the River Avon and tidal currents.

The vessel's swing arm allows for stationary dredging in narrow basins, minimising disturbance to berthed ships and enhancing safety during peak traffic periods.

Beyond performing routine maintenance dredging, Trym can also support capital dredging projects such as berth deepening for larger windfarm support vessels.

The CSD’s high-volume hoses and discharge flexibility enable efficient material relocation to designated spoil grounds, reducing environmental impact.