Painting in challenging conditions

Tallink’s passenger ferry Star I was in drydock in early February at Turku Repair Yard in Naantali where the vessel’s hull and sides were repainted in challenging conditions using Jotun products supplied by Nor-Maali. The seven-day docking took place outdoors, posing challenges to the progress of the work.

Star I returned to Tallink’s service after a two-year break. As part of this, significant changes were made to the vessel’s exterior, including colour update and the addition of company logos.

Since the drydocking was conducted outdoors, weather conditions presented some challenging conditions to the work schedule. During the repainting of Star I, temperatures ranged between -4°C and +5°C, with humidity occasionally reaching nearly 80%. Although precipitation was avoided, the cold temperatures and winds from the sea made painting more difficult.

In such challenging conditions, epoxy coatings are particularly susceptible to amine blush, which can weaken adhesion and affect the quality of the paint surface. Additionally, polyurethane coatings may lose gloss in cold temperatures. For this reason, products that can be painted at low temperatures and that enable quick overcoating were chosen for docking.

Tallink’s Star I before it was repainted

Thorough surface preparation in challenging conditions

Before painting, the treated areas were high-pressure washed (min. 220bar) to remove water-soluble salts and other contaminants. After washing, the damaged areas were blast cleaned to Sa 2½. In addition, edges of existing paint were feathered in order to have the best possible corrosion protection at the overlap of old and new paint.

Due to temperatures fluctuating above and below freezing in the challenging conditions, blasting dust adhered tightly to the painted surfaces and had to be removed before overcoating. During this docking, freezing conditions prevented the outer surfaces from being washed with water, so they were cleaned with cloth rags before applying the topcoat.

Five-day completion in challenging conditions

The drydocking focused on the maintenance painting of the vessel’s exterior. The products used included the epoxy primer Jotacote Universal N10, the vinyl epoxy tie coat Safeguard Universal ES, the antifouling coating SeaQuantum Classic S, and the polyurethane topcoat Hardtop XPF. Jotacote Universal N10 was used for touch-up, while the other products were applied as full coat.

Star I received a new antifouling coating on its hull and a fresh topcoat on its sides. The flat bottom, side bottom, and boot top were painted with SeaQuantum Classic S. Before antifouling, the side bottom and boot top were first treated with Jotacote Universal N10, followed by Safeguard Universal ES. The topside was painted with Jotacote Universal N10 and Hardtop XPF.

Due to the tight schedule, coatings were selected that could perform in cold conditions and be quickly overcoated. The painting work in challenging conditions was completed in five days, after which the vessel was ready to resume service.

Tallink’s passenger ferry Star I after repainted was completed