Harbour works planned for remote Scottish islands

A second tendering process will go ahead for a new ferry and infrastructure at two harbours in the remote Scottish Shetland Islands.

Early information has been released for the harbour works at Grutness on the main island and North Haven on Fair Isle.

Both harbours will need to be dredged so the new ro-ro vessel can be accommodated, with a new quay built at Fair Isle.

Dredging needs to increase the water depth to 4.5 metres, with more than 5,000 tonnes of material removed, including 1,450m³ of rock. This will be done with a barge-mounted excavator, then deposited at a designated sea deposit site using the bottom-discharge method.

The new quay will add to the existing 80m quay and breakwater, and include a 14m linkspan for berthing the new vessel.

Once dredging has been completed, concrete foundations will be cast at the site with steel dowels inserted into the bedrock to create a level footing for pre-cast caissons to be installed on top.

A concrete mattress will be installed on the breakwater behind the caissons to prevent fine aggregate backfill being lost in the breakwater, instead using it to infill between breakwater and caissons. Concrete deck panels and block paving will be placed on top of the caissons and backfill aggregate.

A similar method will be used to install the linkspan, with jacking frame cylinders on top of the support structures with an A-frame to support.

A new slipway will replace the existing steel one, again to accommodate the larger ferry.

At Grutness, plans are in place for an extended pier and rock armour.

Costs estimated in November 2022 at €34.7 million have risen by almost €20 million to up to €53 million in January 2024. It will be part government funded.

The new ferry will replace Good Shepherd IV, which can carry 12 passengers between the main Shetland Island and Fair Isle, the most southern of the archipelago some 24 miles away, which has a population of 65.

“Shetland Islands Council will engage with potential contractors in the coming weeks to share outline plans for the project ahead of the formal retendering process,” says the local council. “The re-tendering process is expected to extend the contract award until early next year, for work to get under way in the spring of 2025.”