Belzona Repairs Scupper on a Navy Vessel

KHIA ID: 10287
Industry: Military (MILI)
Application: FPA-Floor Problem Areas (FPA)
Substrate: Carbon steel
Customer Location: Devonport, New Zealand
Application Date: April 2026
Products: Belzona 5831 (ST-Barrier)
Problem: The scupper aboard this particular vessel is exposed to salt water and had become badly corroded, if the corrosion had been allowed to progress further then the scupper may have begun to leak and salt water could have penetrated into the lower decks of the ship causing structural damage which would have necessitated time consuming and expensive repairs

The original condition of the scupper

After surface preparation with a power file

Two coats of Belzona 5831 (ST-Barrier)

Condition of the scupper after 1 month in service

Application Situation
Tight confines and geometries made surface preparation and salt removal particularly challenging, A power file was used to remove the majority of the corrosion to a best effort basis. Belzona 5831 (ST-Barrier) was selected for its exceptional tolerance higher salt levels, and adhesion to poorly prepared substrates. Belzona 5831 (ST-Barrier) was applied as a two-coat system to an approximation of WFT specified (due to the tight nature of the drain it was not possible to accurately test this)
Application Method
A power file and abrasive paper was used to reach inside the scupper and remove as much of the corrosion as was possible. This was then vacuumed out. Solvent was used to wash the prepared substrate to remove any dust / oil or grease that may have remained.

Belzona 5831 (ST-Barrier) was mixed and applied using a radiator brush and a mirror to ensure that the entire scupper was coated. The first coat was scrubbed into the prepared surface with a circular scrubbing motion to ensure the best possible adhesion. The second coat was applied with care to ensure that there would be no pinholes or thin DFTs and that the finish would be aesthetically pleasing.
Belzona Facts
To cut out and replace a scupper would have necessitated an extended stay in dry dock at great expense, the Belzona alternative was carried out in 8 locations over two days, at a greatly reduced cost and successfully offset future degradation of the asset.
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