Anchoring the future for high-energy aquaculture

Tidal energy technology specialist Sustainable Marine Energy Ltd, the University of Dundee, marine equipment supplier Gael Force Group and the Scottish Aquaculture Innovation Centre (SAIC) are exploring the development of a ‘groutless’ anchoring approach, derived from techniques currently used in marine energy sites.

While concrete or steel anchors are suitable for existing sites, the technology will enhance the options available for high-energy locations with solid rock on the seabed, SAIC said in a press release.

Ground lock

The new approach involves drilling holes into the rock for screw-type anchors and is focused on reducing the cost, weight, and environmental impact of anchoring. It will use much lighter anchors which form a mechanical ground lock without the need for resin or grout – similar in concept to plasterwork screws that come with a wall plug already attached. The lighter weight of the anchors allows operators to use more modestly-sized, readily available vessels for deployment.

Using a remotely-operated drilling rig positioned from a workboat also enables operators to be more precise with installation in deep-water, high-energy sites. The use of low-noise rotational drilling will minimise disturbance to the marine ecosystem and damage to the seabed, while the anchors would be fully removable and potentially re-usable.

Strong Scottish team

Andy Hunt, chief engineer for anchoring and connectivity at Sustainable Marine Energy, said: “For some time we have seen applications in other sectors that would benefit from adaptations to our rock anchoring technology.

“This project brings together a very strong Scottish team of project partners with the appropriate skill set and experience to develop the right rock anchoring solution for the aquaculture market. Together, we can quickly begin to unlock the sector’s latent potential, by opening up areas hitherto unsuitable for aquaculture farms.”

Michael Brown, Reader at the University of Dundee’s Geotechnical Engineering Research Group, said: “While it is easy to design a heavy and expensive rock anchor that works well in all scenarios, we need to refine the anchoring system specifically for aquaculture application.

Scale-model testing

“To achieve this, we will use both scale-model testing and calibrated numerical simulation of the rock anchor systems under realistic operational conditions. This is a specialist area of expertise at the University of Dundee, currently being used to develop foundation and anchoring systems for tidal stream generators and future floating wind farms.”

Locating operations in deeper, higher energy waters could potentially reduce gill health issues, sea lice problems and disease risk for salmon farming. It could also lead to an increase in the industry’s capacity, by allowing the development of larger farms.

Polly Douglas, aquaculture innovation manager at SAIC, said the anchor development “builds on many of our previous projects around the prevention of sea lice, gill health, and environmental impact by adopting approaches taken in other sectors and applying them to aquaculture”.

The total project cost is £91,000.