Ships & Maritime Structures

• Splash-zone corrosion on hull plate, pilings, and structural members in the wet/dry tidal cycle.
• Ballast-tank coating breakdown from cyclic immersion and crevice corrosion.
• Hull plate pitting and pinholes from microbially influenced corrosion (MIC).
• Stern-tube and rudder cavitation from propeller wake disturbance.
• Pipework and deck-equipment corrosion from salt spray and wash-down.
• Bolted-joint and flange degradation on topside piping.

The marine repair window

Repair work on a vessel typically has to fit one of three windows: an in-service voyage repair, a port-call layby, or a planned dry-docking. Belzona is specified into the first two windows because the systems cure cold, do not require hot work, and tolerate a damp or oil-contaminated substrate.

Belzona product families used on marine assets

Surface-tolerant in-service repair

Belzona 1212 is a surface-tolerant epoxy composite engineered for application to damp, oil-contaminated, or underwater steel. Field uses include hull-plate pinhole sealing, ballast-tank patch repair, splash-zone rebuilding, rudder repair, and stern-tube work. The product is applied without removing the vessel from service for many of these scopes.

Splash-zone and immersion coatings

Belzona 5831 (ST-Barrier) is the splash-zone choice for tide-line and riser repairs, including corroded riser pipe rebuilding above the waterline. Belzona 5811 (Immersion Grade) handles long-term immersion above the splash zone and inside ballast tanks once the substrate is reasonably dry.

Cavitation and stern-tube assets

Stern-tube cavitation, propeller-shaft sleeves, rudder bearings, and bow-thruster housings are typical Belzona 1311 / 1321 / 1341 scopes; the elastomeric Belzona 2141 (or its successor in the 2000-series) is selected when the surface is required to absorb cavitation energy rather than resist it rigidly.

Approvals and class

Approvals (ABS, DNV, Lloyd's, NSF for potable-water service inside the vessel) attach to specific product codes, not to Belzona as a brand. Belzona Baton Rouge confirms the active approval and effective revision against the surveyor's requirement for the actual scope before specifying the product. We do not assert a blanket marine approval that the surveyor will then have to disprove.

Where in-service repair beats dry-docking

If the scope is a localized hull-plate pinhole, a ballast-tank patch, or a riser splash-zone rebuild, an in-service Belzona repair lets the vessel keep its schedule and defers dry-docking to the planned interval. We do not recommend in-service composite repair as a substitute for dry-docking when the underlying steel has lost code-allowable wall thickness; we ask for the latest UT thickness map first.