The Crinan Canal extends between Crinan and Ardrishaig in Argyll and Bute in the west of Scotland and is operated by Scottish Canals. The full Crinan Canal has been prioritised for gate replacement by Scottish Canals as part of their asset management programme for all lock gates in Scotland. The upgrade and replacement of the gates along the canal is vital to maintain the navigation of the historic waterway.

The first phase of the gate replacement is between Locks 1 and 4, located in Ardrishaig. The main contractor for the replacement works is AMCO Giffen.

MHB were commissioned by AMCO Giffen to undertake permanent and temporary civils design for various elements associated with the replacement of the gates at Locks 1-4. The main works included the design of new actuator pits which would house the hydraulic rams used to open and close the gates at Lock 1. These gates are termed the ‘sea gates’ due to their location at Loch Gilp, and are significantly larger than most along the canal.

Given the complex nature of the works and various interfaces, MHB were required to liaise with others to ensure the designs satisfied each requirement and could be completed without creating issues elsewhere in the works.

As part of the temporary works, we carried out the design of crane foundations to facilitate the removal of the existing gates and installation of the new lock gates at four locks on the Crinan Canal.

Permanent and temporary civils design of the following elements from Locks 1-4 on the Crinan Canal:

  • New actuator pits at Lock 1 which house the hydraulic rams, used to open and close the new lock gates
  • Pintle and quoin liner fixing details
  • Cill details
  • Cable duct routes and equipment plinths
  • Conversion of an existing toilet block and shower facility into equipment housing and plant room
  • Design of crane foundations
  • CAT 3 checks of temporary sheet piles

Works completed April 2021, with exception of the actuator pits which are expected to be completed by the end of May 2021.


Crinan Temporary works (photos courtesy of AmcoGiffen)


On the Caledonian Canal we carried out a CAT 3 check of the temporary sheet piles to allow the works to be carried out at Gairlochy, this allowed the gates to be held in their closed position while adjustments were made to the seals prior to casting the new cills, ensuring a water tight fit.

  • Inspection of Gairlochy stop log grooves to review their condition and identify defects which may be repaired prior to watering the lock.


Gairlochy Stop Log Groove Inspections (photos MHB Consultants)