Project details
Mid Channel Rock Beacon is located at the mouth of Milford Haven, and is in a position that is exposed to both aggressive weather and sea conditions. The beacon was constructed in 1966, and has been in constant use ever since to safely navigate ships into the Port of Milford Haven. The beacon structure is rock bolted onto the sea bed, culminating in a single tube running up to 23m above CD. In addition to housing a navigational light, the structure also holds meteorological and wave monitoring equipment. The project involved the refurbishment and strengthening of this navigational structure.
Initial works included the completion of a comprehensive survey of the structure to determine its exact condition, and to ensure the work scope was clearly defined. Given the location of the beacon, an 850T Jack Up barge was required to access and complete the works. The barge was loaded out with all plant and equipment including a 200T Crawler Crane, and transported from the Port of Milford Haven.
Upon accessing the structure, the site team removed the tower house complete with all fixings. The tower house was then transported back to the port and refurbished. The access ladders and fendering were then removed from the structure, with divers used to assist when removing low level fixings. The dive team were then responsible for the completion of repairs to the existing concrete foundations. Once placed on the Jack Up Barge, the ladders and fenders were then cut into sections ready for disposal. The shaft of the beacon structure was then cleaned of all marine growth and corrosion. A preassembled steel sleeve complete with ladders and fendering was then lifted into position, with the site team confirming orientation of the access ladders prior to lowering the steelwork over the existing beacon. Once in position, divers were used to confirm that the sleeve was equally spaced. A grout plug was then formed at the base of the sleeve to secure the structure. Using predrilled holes, grout was then pumped into the annulus between the existing structure and new sleeve, before being allowed to cure. Using a multi-cat, the refurbished tower house was then transported back to the beacon before being loaded onto the barge and lifted into position. The jack up barge was then transported back to the port and demobilised.
Given the remote location of the beacon, approximately 4.5 nautical mile from the Port of Milford Haven, significant pre planning was required to identify and maximise suitable weather conditions. In order to access the structure, daily crew vessel transfers were required. Due to the location of the structure, the site team were required to undertake specialist offshore safety training.
