New eco-mooring may end anchor bans
Trials of a new kind of eco-mooring are underway in the South West which environmentalists believe could ease conflict over sailors anchoring in Marine Protected Areas (MPAS).
The National Marine Aquarium (NMA) has laid five Stirling Eco-moorings at Cawsand Bay in Cornwall as part of a joint project involving Princess Yachts and the Marine Conservation Society (MCS).
If successful, these types of moorings could be installed at other MPAS around the UK coast.
They differ from standard moorings by using a two-metre screw pile rather than a traditional concrete block to anchor to the sea bed, helping to reduce any damage to the sea floor. The NMA Stirling Eco Mooring, which is a chain, with small buoys attached along its length, is then connected to each pile, allowing the chain to be lifted to the larger buoy on the surface. The vertical uplift capacity of the screw pile is reported to be over nine tonnes, compared to one tonne if using a twotonne concrete block. This means the riser chain is not sweeping through vulnerable areas, like seagrass beds.
The MCS principal specialist on MPAS, Dr Jean-luc Solandt, said at Cawsand it is hoped the moorings will result in the recovery of damaged seagrass beds.
‘If the project is successful we hope it will lead to other areas using this cheap and practical technology where there has been animosity between local conservationists and boat owners over calls for anchor bans,’ he stressed. ‘These eco options offer a potential solution to future stand-offs,’ added Dr Solandt.
Seagrass meadows are a crucial part of the marine ecosystem, stabilising sea beds, and hosting larval and juvenile fish and seahorses.
The NMA has been testing prototypes of the Sterling Eco-mooring along Devon’s south coast for the last four years, and it is the funding from Princess Yachts that has allowed it to produce a finished design.
The trials are being welcomed by the community organisation, Boat Owners Response Group (BORG) which promotes rights of navigation, anchoring and mooring for boaters in the context of marine conservation zones and other legislation.
It is, however, calling for the new system to be ‘rigorously tested in real-life conditions’.
‘Does the system, with its multiple mini-catenaries suspended from floats, offer adequate shock protection from wave impact? Will the line of floats and chain get tangled up in heavy breaking seas?’ questioned BORG’S spokesman Michael Simons.
‘And while the six mini-floats shown in calm water are clustered close together, what happens in Force 4 or Force 6 conditions? Will the line of floats and chain get stretched out by the wind and waves to form a hard-tosee trip-wire (trip-chain) for passing vessels, snagging keels or destroying propellers? And if so, who is liable for the resulting damage?’
Jon Reed, also from BORG, outlined a number of technical issues with deploying environmentally-friendly moorings in UK waters including increased costs, and the fact they don’t work as a drying mooring.
BORG also believes that anchoring in eelgrass, ‘causes little disturbance, a view backed by many scientific papers and members’ observations.’
It said a 2018 study showed Dorset’s Studland Bay had the highest density of seagrass plants and most consistent seagrass meadow out of 13 eelgrass sites surveyed along the south coast, even though it is popular with boaters.
ABOVE: Each mooring is secured to the seabed by a two-metre screw pile, which has a vertical lift capacity of over nine tonnes
Subsurface buoys means the riser chain is lifted above the sea bed