A North of England precision engineering firm, Accu, has provided crucial components for the development of the world’s first underwater seagrass harvester, a groundbreaking marine conservation innovation.

Based in Yorkshire, Accu collaborated with Tandem Ventures, a science and conservation technology specialist, and marine organisation Project Seagrass, on the project. The new machine is designed to rapidly harvest seedpods, a vital step in efforts to restore damaged seagrass meadows globally.

Seagrass is widely known as a critical ocean habitat, providing sanctuary for juvenile fish and stabilising coastal sediments. These 'ocean meadows' are also an essential tool in the fight against climate change, capturing carbon up to 30 times faster than tropical rainforests. However, conservation groups estimate that the UK has lost as much as 90% of its seagrass beds, spurring the urgent need for scalable replanting solutions.

The Tandem Ventures team designed a towable underwater harvester capable of delicately trimming the seagrass blades, collecting the seedpods, and filtering them to the surface. The design required materials that were robust enough for the harsh marine environment, yet precise and non-damaging to the surrounding wildlife.

Accu supplied marine-grade A4 stainless steel fasteners to secure the structure. These components, which included M6 Torx screws for the frame and 3mm Polyfix screws for the onboard datalogger, were chosen for their corrosion resistance and ability to maintain joint stability under high-pressure underwater operation. Testing showed they maintained integrity even after prolonged submersion.

Patrick Faulkner, Lead Engineer at Accu, explains: “The quality of the fasteners was crucial to the project’s success. We recommended our marine-grade stainless steel fasteners due to their exceptional resistance to saltwater oxidation, plus their proven strength in mechanical assemblies exposed to extreme conditions. The result was a system that performed exactly as designed; being watertight, resilient and easily maintainable by divers and engineers alike.”

He added: “We are extremely proud to have played our part in this innovative project that is set to solve an important environmental challenge. Our components are designed for durability, accuracy and performance and it is very satisfying to see them being used on a project to like this. This isn’t the first time we have partnered with Tandem Ventures and these innovations are truly pioneering in meeting crucial environmental needs.”

The prototype, nicknamed 'Thunderbird 4', was successfully trialled in North Wales, proving effective at collecting seedpods via its twin-barrel filter system. The design has since been upgraded with features like reinforced adjustable legs for precise cutting height and a blade guard to shield wildlife.

The harvester is reported to be up to 100 times quicker than manual collection methods, which is set to revolutionise the scale of global seagrass restoration efforts.

Edwin Towler, Design Engineer & Wildlife Presenter at Tandem Ventures, said: “We would like to thank Accu for their support in making this project possible. The result is a seagrass harvester that is up to 100 times faster than manual collection, with huge implications for restoring seagrass meadows in the seas around the UK and throughout the world.”

This marks another conservation collaboration between the two organisations. Earlier this year, Accu supplied fasteners, including high-performance PEEK polymer bolts, for a Tandem Ventures project with WhaleWise. The lighter polymer bolts replaced heavier stainless-steel alternatives, significantly increasing drone flight times for monitoring humpback whales.