Make the working position recognisable from the vessel
A barge arriving at a foundation needs a recognisable working reference. A tug approaching a construction area needs to identify the agreed access and avoid underwater work. SVC installs marker buoys against a numbered position schedule so the vessel crew, marine coordinator and diving team use consistent references.
Define whether each buoy marks a working point, boundary, temporary obstruction or an identified underwater item. The position schedule should show the coordinate system, drawing revision, identification and required visibility arrangement. Official navigation marks follow the approved marine arrangement and competent authority’s requirements.
Distinguish marking from holding a vessel
A construction marker is not automatically a mooring point. Its attachment may be designed only to keep that marker in position. A vessel mooring must account for the particular vessel, environmental loads, seabed and mooring geometry through a suitable engineering design.
SVC’s diving work covers the specified underwater connections, inspection and installation attendance. If the client requires a barge mooring, include the design, load-rated components, installation checks and acceptance requirements in a separate scope. Do not attach a tug or barge to a marker merely because it has a visible lifting or connection eye.
Prepare the buoy, attachment and seabed information together
Provide the buoy specification and the intended anchor or sinker arrangement, with chain or rope, shackles, swivels and connection drawings. State who supplies each component and who verifies compatibility. Component identification and available certificates are checked against the installation schedule before dispatch.
The design needs local water levels, currents, wave exposure and seabed information. Chain length, anchor or sinker size and the allowable movement area are selected for that arrangement. The service scope includes identifying any nearby cables, structures or prohibited anchor areas before the underwater installation starts.
Installation and position verification
SVC coordinates the underwater attendance with the lifting and vessel teams. The agreed method identifies the equipment to be lowered, the connection points to be checked and the point at which personnel may approach. Divers inspect or make the specified underwater connections after the relevant lifting and vessel hazards have been controlled.
Record the buoy’s observed surface position separately from the installed anchor or sinker position. Wind, current and tide can move a buoy within its designed watch circle. A GNSS position at the buoy alone does not prove the exact position of its seabed attachment. Agree the survey method and the positional tolerances for the task before installation.
Maintenance for chains, shackles and buoy condition
SVC checks the accessible underwater attachment, chain wear, loose or damaged fittings, entanglement and movement affecting the buoy’s function. Surface checks can include the buoy body, identification and specified lighting equipment. Cleaning and component replacement follow the agreed maintenance scope and handling plan.
Keep the original component sizes and acceptance limits available when assessing wear. A photograph documents visible condition; a wear measurement needs the stated measurement locations and suitable equipment. Record replaced components and the resulting configuration so later inspection compares the right parts.
Check after storms, vessel contact or changed construction stages
A missing, displaced or damaged marker needs prompt attention from the marine coordinator. Advise the site team of the affected identification and position, then inspect the arrangement under an agreed work plan. The revised position schedule and vessel briefing must reflect any relocation.
SVC also retrieves temporary markers and underwater fittings when the construction stage finishes. Define recovery quantities, lifting arrangements, disposal or return of components and the final condition of the work area. Periodic underwater maintenance can retain the records for markers that remain in service.
What does a buoy installation handover contain?
A practical handover identifies each buoy and its purpose, drawing revision, installed components, position records, underwater photographs or video, completed checks and outstanding items. Where the buoy includes a light, keep its test record with the surface equipment check. Engineered moorings also need the specified engineering acceptance documents.
What should SVC receive before mobilisation?
Email [email protected] the buoy schedule, coordinates and datum, design drawings, supplied materials, seabed and water-level information, vessel plan and installation window. Identify who approves positioning and who controls marine traffic. For the wider work programme, see wind farm diving in Ky Anh.