Plugging & Blanking

Nereus Subsea Services specializes in the fabrication of blanks, and plugs designed to restrict water ingression and enable safe internal repairs. Our repair services cover a wide range of needs, from valve replacement to internal pipeline overhauling. This can help a vessel avoid dry docking, resulting in significant savings in time and money. Blanking of sea chests/plugging of intakes or overboard discharges to assist with inboard repairs is one of our specialties.

Nereus subsea's plugging and blanking system is simple and easy to use, and can be fitted by our experienced divers. Our design incorporates an adequate safety factor, and all plugs and blanks are quality checked to the highest standard. Many of the underwater blanking systems also carry class approval from the major classification societies. The system is designed so that it can be easily installed and operated by our divers, and is also able to withstand the high pressures that are often found in subsea environments. This makes it an ideal solution for a wide range of applications, including sealing off leaky pipes and preventing the ingress of water into sensitive equipment

Underwater ship plugging

Underwater discharges, such as seawater and oil, are essential for the safety of ships and offshore facilities. To prevent costly delays or unscheduled dry-dockings, underwater blanking and plugging operations can be performed. Blanking technology is also suitable for semi-submersible installations and other offshore structures that cannot easily be brought to a docking facility. FPSOs that are on station for 10 to 25 years rely on blanking technology to remain in service and remain in class. The blanking method is typically used for smaller repairs that can be carried out quickly and efficiently. However, more extensive repairs may still require the ship to be drydocked in order to complete them.

Underwater ship blanking

If you are considering blanking of sea chests or plugging of intakes or overboard discharges as part of your onboard repair strategy, it is important to keep in mind that Nereus Subsea offers blanking of Seachest repairs and underwater plugging services which is a very cost-effective method of changing defective valves and repairing sea chests plating, while afloat during normal ship operations.

Our diver technicians will remove defective valves, piping, or plating from your overboard or sea chests. The ship’s crew will then remove any steel pieces that need repairs and make any necessary repairs to the vessel.


When replacing a valve the following information are important:

  • Sort of valve; butterfly, globe, gate, ball etc.

  • Face-to-face dimensions

  • Flange diameter, bolt circle, the quantity of bolts

  • Material and trim material.

  • Rating and connection, JIS, DIN or ANSI standards.
Sip plugging and blanking


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