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Infrastructure Upgrade

Briggs Marine Contractors was asked to carry out the removal of temporary works installed by the main contractor, which allowed them to carry out there contract works of widening the dock gates for the new Aircraft Carriers. The temporary works to be removed included a rock bund, steel sheet piles, steel tube piles, steel tube bracing and a reinforced concrete anchor wall. These items together had to provide a protective outer cofferdam from the Firth of Forth from which the permanent works were carried out in the dry.

Our Work

The works had to be carried out progressively with the rock bund being removed first using a long reach excavator located on a barge with the material being shipped via carrier barges to an offloading facility within the naval base. The sheet and tubular piles were removed next using a crane barge by divers cutting them at bed level, loading them onto the barge and unloading them at the same off loading facility.

To complete the works the reinforced concrete had to be broken up by a long reach excavator with hydraulic breaker on the barge with the demolished material once again being removed using carrier barges to the offloading facility.

  • 11000t 75mm rock
  • 200t steel sheet piles
  • 50t steel tubes and bracing
  • 1200m reinforced concrete


Works were carried out in an operational naval base and on a tidal basis. We also managed dive teams for exothermic cutting and underwater breaking


  • Clark Avon spud leg barge
  • Harry McGill Crane barge
  • BC6099 & Forth Quarrier 1 carrier barges
  • CAT 330 & CAT345 long reach excavators
  • 2.5t Hydraulic Breakers
  • Multicats
  • Hydraulic Grab
  • Divers
  • Underwater cutting Equipment