Marine fouling on a vessel’s submerged surfaces increases hull roughness and hydrodynamic resistance. Slime, algae, barnacles and other deposits may reduce speed, increase fuel consumption and place additional load on the main engine. For vessels trading to Northern Vietnam, professional underwater hull cleaning at Hai Phong Port can restore a smoother underwater surface without waiting for the next dry-docking.

Bacviet Shiprepair provides 24/7 commercial diving services for bulk carriers, container ships, tankers, general cargo vessels and offshore units. Our scope can combine hull cleaning with an underwater hull survey, in-water survey support, propeller polishing, sea chest cleaning and photographic reporting. The work is planned around the vessel’s schedule and carried out at a permitted berth or anchorage, subject to local approval and operating conditions

Why Underwater Hull Cleaning Matters

Fouling develops according to water temperature, salinity, coating condition, vessel speed and idle time. Even moderate growth can disturb water flow along the hull. Cleaning may improve propulsion efficiency, reduce unnecessary fuel consumption and help the technical manager assess the condition of coating, anodes and underwater fittings.

• Removal of slime, algae, barnacles and other marine growth
• Improved hull and propeller surface condition
• Reduced resistance and more stable propulsion performance
• Cleaning around sea chests, gratings, rudder and thruster areas
• Early identification of coating damage or visible underwater defects

The cleaning method is selected after reviewing the coating specification and actual fouling. Divers use suitable brushes or cleaning tools and avoid unnecessary pressure on intact antifouling paint. Any exposed steel, loose coating or abnormal condition is reported before work continues in the affected area.

Underwater Hull Survey Before and After Cleaning

An underwater hull survey provides a documented visual assessment of accessible submerged areas. Before cleaning, divers can record the distribution and severity of fouling. After cleaning, the same areas can be reinspected so the Owner, vessel and attending surveyor can evaluate the cleaned condition and any findings that were previously hidden.

The typical survey coverage includes the vertical side shell, flat bottom, bow and bulbous bow, stern, rudder, propeller, bilge keels, sea chest gratings, overboard openings, draft marks and visible sacrificial anodes. Clear underwater photographs and continuous or sectional video are provided according to the agreed inspection plan.

In-Water Survey and Class-Approved Attendance

When the vessel requires an in-water survey in lieu of dry-docking, the inspection scope must follow the requirements of the vessel’s Classification Society. Bacviet Shiprepair can support an in-water survey under the attendance and direction of the appointed Class surveyor. The diving team follows the agreed survey plan, identifies hull locations and supplies real-time or recorded video, photographs and measurements when requested.

Class approval applies to the agreed company, diving personnel, procedures, equipment and/or individual attendance as required by the relevant society. It should not be understood as a general approval for every underwater cleaning operation. Before mobilization, the Owner should provide the vessel’s Class, survey status and specific instructions so that approvals and documentation can be verified.

Subject to the surveyor’s requirements, the inspection may cover shell plating, sea connections, rudder and steering components, propeller, shaft and stern-seal areas, thrusters, anodes, weld seams and previously reported damage. Any suspected defect can be marked, photographed and reported for further assessment. Thickness measurement, non-destructive testing or repair is quoted separately when required and technically feasible.

Where an inspection identifies damage requiring repair, Bacviet Shiprepair can propose underwater hull welding, doubler-plate installation, crack control or other underwater repair methods. Such work is performed only after technical review and, where applicable, approval of the repair procedure by the vessel’s Classification Society. Final acceptance remains subject to inspection and testing by the attending Class surveyor.

Underwater Cleaning Scope

Hull cleaning

The agreed hull area is cleaned section by section so progress can be monitored. The scope may cover vertical sides, flat bottom, boot-top area, bow, stern and appendages. Cleaning standards and excluded areas are confirmed with the vessel before diving begins.

Propeller polishing

Deposits and surface roughness on propeller blades can reduce efficiency. Divers clean and polish accessible blade surfaces and the hub to the agreed finish. They also check for ropes, fishing nets, edge damage, dents or other visible abnormalities around the propeller and rope guard.

Sea chest inspection before cleaning in Haiphong Port

Sea chest inspection after cleaning in Haiphong Port

Sea chest, rudder and thruster cleaning

Marine growth around sea chest gratings may restrict cooling-water flow. Divers can clean high and low sea chest gratings, overboard openings and accessible intake areas. The rudder, stern frame, bow-thruster tunnel, blades and gratings can also be cleaned and visually inspected. Loose or missing grating parts and damaged anodes are documented for the vessel.

Typical Working Procedure

1. Review vessel particulars, underwater drawings, Class requirements and requested scope.
2. Confirm berth or anchorage, schedule, agent coordination and local permissions.
3. Prepare the diving plan, risk assessment, equipment and communication arrangements.
4. Conduct a toolbox meeting and verify vessel-side isolation before diving.
5. Perform the initial underwater hull survey and record pre-cleaning condition.
6. Clean the agreed hull sections and complete propeller or sea chest work.
7. Carry out the final inspection with Class attendance when applicable.
8. Submit the service report, photographs, videos and recommendations.

Safety and Local Permission

Underwater work is coordinated with the Master, Chief Engineer, local agent, terminal and relevant authorities. Before diving, the main engine and shaft movement must be secured, thrusters isolated and potentially hazardous sea suctions or overboard discharges controlled. Diving signals are displayed, communication is maintained and current, visibility and weather are monitored throughout the operation.

Permission for hull cleaning, underwater hull survey or in-water survey depends on the exact location and local environmental rules. Some terminals may restrict diving or in-water cleaning; in that case, the job can be proposed at a suitable approved anchorage. Early confirmation of the working location reduces delay and allows the correct permits to be arranged.

Service Areas in Hai Phong

Subject to permission and site conditions, our teams can support vessels at Hai Phong Port, Lach Huyen and HICT, Tan Vu, Chua Ve, Dinh Vu, Nam Dinh Vu, Hoang Dieu, nearby shipyards and Hai Phong anchorages. We also mobilize commercial diving teams to other ports and anchorages throughout Vietnam.

Reporting and Deliverables

The final report identifies the vessel, IMO number, date, location, diving team and completed scope. It records the areas inspected and cleaned, the observed condition before and after work, and details of propeller, rudder, sea chest, thruster and anode findings. Photographs are labelled by location, while video files are organized for review by the Owner, vessel and Class surveyor.

Visible damage, coating breakdown, missing anodes, loose gratings, ropes or other abnormal findings are clearly stated. For a Class-attended in-water survey, documentation is prepared in accordance with the agreed instructions; final survey acceptance remains subject to the attending Classification Society surveyor.

Please provide the vessel name and IMO number, type, LOA, beam, draft, Class, expected location, ETA/ETD, underwater drawings, last dry-docking or cleaning date, estimated fouling condition, required cleaning areas and reporting standard. For an in-water survey, also send the Class instructions, survey due date and surveyor’s contact details. State whether propeller polishing, sea chest cleaning, thruster cleaning, measurements or real-time video are required.

Why Choose Bacviet Shiprepair?

• Fast 24/7 mobilization in Hai Phong and throughout Vietnam
• Trained commercial divers with many years of practical marine experience
• Modern, well-maintained diving, communication and safety equipment
• Coverage at ports, terminals and anchorages throughout Vietnam
• Class-approved inspection support when required and confirmed
• Combined hull cleaning, propeller polishing and survey attendance
• English technical reports with labelled photographs and video records
• Coordination with vessel, agent, terminal, authority and Class surveyor

Bacviet Shiprepair also provides rope removal, underwater damage assessment, anode renewal, underwater welding and other underwater ship repair services, subject to technical feasibility and approval requirements.

Contact Bacviet Shiprepair

If your vessel requires underwater hull cleaning, an underwater hull survey or a Class-attended in-water survey at Hai Phong Port, send us the vessel’s particulars, schedule, location and required scope. Our team will review the operating conditions and submit a suitable technical and commercial proposal.

24/7 UNDERWATER HULL CLEANING • UNDERWATER SURVEY • IN-WATER SURVEY SUPPORT

Service Areas: Hai Phong | Phu My | Dung Quat | Nghi Son | Cam Pha | Nationwide

8.1. Head Office

No. 25/6/302 Van Cao Street, Hai An District, Haiphong City

Mobile/WhatsApp/WeChat: +84 904 125 520

Email: bacviet@haiphongshiprepair.com

8.2. Ho Chi Minh City (Saigon) Branch

No. 66 Dragon Village, Phu Long, Phu Huu Ward, District 9, Ho Chi Minh City

Mobile/WhatsApp/WeChat: +84 904 125 520

Email: bacviet@haiphongshiprepair.com / Bacviettechco@gmail.com

8.3. Da Nang City Branch

No. 1109 AZURA Building, 339B Tran Hung Dao Street, Son Tra District, Da Nang City

Mobile/WhatsApp/WeChat: +84 904 125 520

Email: quangtrungpr@gmail.com

Updated: August 2026 by Mr. Khanh – Bacviet Technical Dept.

Copyright of this article belongs to Bacviet Ship Repair Company.