Steelpaint has delivered a decisive breakthrough in the renewal of Wilhelmshaven’s Great Sea Lock, applying corrosion protection to some 26,000m2 of steel on one of the world’s largest sluice gates.

At 60m long, 20m high, and with a depth of 10m, the 1700t gate provides access to Germany’s only deep-water port for naval vessels, commercial ships and energy carriers. The completion of the main coating work marks a significant step forward in a challenging project that started in 2018.

Steelpaint’s Stelpant coating system was selected after a two-component epoxy system from another supplier was found to be incompatible with an autumn/winter application, when freezing temperatures and near-saturated humidity can make epoxy coatings unusable.

Muehlhan Germany GmbH, which worked together with Hermann Maschinenbau GmbH in a working-group for port authority WNA Hannover & WSA Weser-Jade-Nordsee, opted for Steelpaint’s single-component polyurethane system Stelpant, which can cure at temperatures down to -5°C with a relative humidity up to 98%. Its use allowed the coating application work to continue through winter, ensuring the gate could be floated back into position and reinstalled for interim use.

The coating package consisted of a 75µm zinc-rich-primer of Stelpant-PU-Zinc followed by two 225µm coats of Stelpant-PU-Combination 300. Together, the layers provide advanced corrosion protection against saltwater, abrasion and mechanical stress in one of Europe’s harshest marine environments.

The zinc primer provides cathodic protection and excellent adhesion, while the polyurethane intermediate and top coat delivers abrasion resistance, flexibility and durability even under aggressive marine exposure. The system is certified by the Federal Waterways Engineering and Research Institute in Karlsruhe for use in hydraulic steel structures and for environments from Im1 to Im3 under DIN EN ISO 12944-5.

“This was one of the largest and toughest projects we have been involved in the last few years, but it showed exactly what our technology can do,” said Fynn Baumfalk, Key Account Manager at Steelpaint. “The schedule slipped again and again and even now some areas remain unfinished, yet our coatings went on when and where they were needed and performed exactly as intended.” Our market presence in Wilhelmshaven is growing more and more. First the Jade-Weser-Port, now the gate refurbishment and currently in progress is the refurbishment of sluice “Hooksiel”.

The main corrosion protection on the refurbished gate is complete, though minor rework is required and some hot work also needs to be redone before recoats.

Baumfalk confirmed that the Stelpant coating system will also be used in these areas, with full commissioning of the gate expected in 2026.

The Wilhelmshaven Sea Lock sits at the mouth of the Jade, where the river meets the North Sea. Its location exposes it to salt corrosion, tidal erosion and abrasive silt, demanding the highest levels of protection.

The lock regulates water levels in Wilhelmshaven’s inner harbour, strengthens flood defences and provides safe access for both naval and merchant fleets. The port handles a major share of Germany’s crude oil, coal and LNG imports, while JadeWeserPort is the country’s only deep-water container terminal and the German Navy’s principal North Sea base. It has a natural depth of about 18m and can accommodate ships with an loa of up to 430m and a 16.5 m draught.

The success of the Stelpant coating could see Steelpaint selected for further phases of JadeWeserPort dock’s wider renewal. Three entirely new dock gates are being discussed for commissioning towards the end of the decade. A feasibility study updated in 2019 confirmed the economic viability of a second container terminal 2km north of the existing one.