Restoring the Historic Dunoon Victorian Pier

Introduction

In May 2015, Shearwater Marine Services was tasked with the vital repair and replacement of various timber elements of the Dunoon Victorian Pier. The project was a challenging blend of surface and underwater works that required specialised tooling and a diverse set of skills.

Challenge

The pier, an important historic structure, required urgent replacement of its deteriorating timber piles, splice boxes, timber bracing, waling beams, and the timber deck. The challenge was to complete these extensive repairs within a 12-week timeline, requiring both surface and underwater operations, and utilising a variety of specialised equipment such as spider cranes, barges, mobile pontoons, hydraulic chainsaws, and underwater tooling.

Solution

Collaborating with George Leslie Ltd and A&B Council, Shearwater developed an effective work plan. Timber piles were replaced by fitting a lifting arrangement at the pile top, removing all bolts and metal fixings, and cutting the pile at the new splice box level. New piles were then installed in a similar process. Bracing members were replaced using chain hoists slung from the timber deck, allowing old braces to be lowered onto a waiting barge below and replaced efficiently. To offer additional protection to the piles at their base, scour protection in the form of grout bags was installed. A trench was airlifted around the pile base, the grout bags were pinned to the seabed, and additional layers were added and pinned to ensure they would set together and remain immobile.

Results

Despite the complexity of the project, Shearwater Marine Services successfully completed the Dunoon Victorian Pier repair within the given timeline. The pier was reopened on schedule with significantly increased lifespan and capacity, thanks to the extensive repair works. All work was carried out without incident, and the final result was deemed a success by all stakeholders.

Conclusion

The Dunoon Victorian Pier Repair is a testament to Shearwater Marine Services' expertise in tackling challenging underwater engineering projects. By successfully replacing the pier's vital elements within the required timeline, Shearwater demonstrated its commitment to delivering high-quality, efficient services that preserve and enhance vital infrastructure. This case study exemplifies Shearwater's dedication to engineering excellence, timely delivery, and innovative solutions in complex environments.

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