Bute Dry Dock Repairs

Bute Dock lies in Cardiff Bay and is a former operational dry dock, part of the extensive wider dockland that formed the largest coal exporting port in the world during the late 19th and early 20th centuries. Constructed in 1884, it comprises a mass mortared stone dry basin and is connected to the larger Roath Basin/Roath Lock to the north. Water levels in the dock were controlled via a series of sluices, pumps and valves with a floatable steel caisson forming the dock gate, allowing ships to enter the dock when water levels were equalised and maintaining the water level difference between the two when the Bute Dock was emptied. Bute Dock has long since been disused, but the structure is largely intact and both the dock walls and the dock gate caisson are deemed to be of historic value and are consequently Grade II listed by Cadw. The dock is owned by the Welsh Government and is part of it’s wider land holding in the Cardiff Bay Area. Today, Bute Dock is hydraulically ‘open’ to the impounded Cardiff Bay and has a permanent similar water level. Although the dock gate caisson is an historic structure, it continues to form an important function by maintaining the higher water level in Roath Basin/Roath Lock and prevents water leakage into the lower impounded bay. Welsh Government has commissioned a number of condition surveys of the structure which confirms the caisson to be in fair to poor overall condition with numerous defects noted. Scope of Works To safeguard the caisson in the short to medium term, Welsh Government is seeking an experienced specialist marine contractor to design and implement a series of repairs in accordance with the recommendations of the condition survey reports and under the terms and conditions of a Listed Building Consent, which is currently being sought. The repairs are likely to comprise cutting damaged and perforated sections of the caisson and/or welding of new steel ‘patches’, generally at or above the water line but which may extend below the water line. Working from temporary pontoons may be necessary and a specialised team with approved welding certificates will be required. Heavy cranes are expected to be needed to lift materials into place. The objective is to undertake sufficient refurbishment/repair work to safeguard the structure for the next 10 to 20 years in which time it is anticipated a permanent solution for the management and development of the historic dock will be implemented. Requirements The successful contractor will have extensive experience of planning, designing and undertaking similar repair and refurbishment work on historic dock structures and will have an impressive track record of managing health and safety in such challenging environments. A specialist labour team will be required with approved welding certificates and divers may also be needed.