A major milestone in the plan for subsea tunnels between the Shetland mainland and Yell and between Yell and Unst has been reached with the commissioning of sonar investigations and a report which will make recommendations for the seismic survey locations that will contribute to the determination of the alignments of the tunnels

read the rest at The Unst and Yell Tunnel Action Groups (UTAG & YTAG) website:

https://shetlandtunnels.co.uk/shetland-tunnels-major-step-forward/