Laminating a vintage wooden launch (traditional planking)

Restoring a wooden boat is a complex operation that requires both technical expertise and the use of suitable products. This article details the complete epoxy lamination process carried out on a 90-year-old hydrographic launch from the French Navy, built after World War II at the Belot shipyard in Cherbourg.

This vessel, named La Découverte, showed clear signs of ageing: the 22 mm mahogany planking, sanded and scraped many times over the years, had become fragile, and the corroded copper rivets were no longer able to ensure sufficient watertightness. The structural integrity of the boat was compromised, making its use at sea uncertain and risky.

To restore the vessel and give it a new lease of life, the owner chose to laminate the entire underwater hull with epoxy resin and fiberglass fabric. This solution not only restores the boat’s structural strength, but also ensures perfect watertightness and long-term protection against moisture and marine aggression. Below is a detailed breakdown of every step in the process, from material selection to final finishing.

Why laminate a wooden hull with epoxy resin?

Laminating a wooden boat involves reinforcing the structure by applying fiberglass fabrics impregnated with epoxy resin. This process allows you to:

• Improve the boat’s rigidity and structural stability

• Ensure perfect watertightness

• Significantly extend the lifespan of the hull

• Simplify future repairs and maintenance

In the case of La Découverte, lamination was essential to replace deteriorated caulking, reinforce the planking, and stop water ingress.

Materials and products used

Wood epoxy resin: WOODPOXY PLUS

• High impregnation capacity

• Good mechanical strength and moisture resistance

• Adjustable working time depending on the hardener used

  • WOODPOXY FAST PLUS: fast

  • WOODPOXY SLOW PLUS: slow

Fiberglass fabrics

• BX 450 g/m²: used for the rabbet, angles, and transom (in 100 mm and 200 mm strips)

• BX 600 g/m²: used for the rest of the hull (two crossed layers)

• Fabric orientation at 45° for improved structural strength

Epoxy fairing compound: Mixfill 10

• Lightweight and easy to sand

• Perfectly suited for filling wood irregularities

• Easy application with a smooth texture

Finishing primer: Epoxyguard IM409 (Map Yachting)

• Watertight barrier

• Adhesion base for antifouling

Lamination layout

The lamination was carried out in three phases:

• Phase 1: Transom

• Phase 2: Rabbet

• Phase 3: Remaining underwater hull (divided port / starboard)

For each phase, the method was similar.

Step 1: Hull preparation

The first stage involved carefully preparing the hull before lamination. The boat was stored ashore in a shed for two years, allowing the wood to dry properly until its moisture content dropped below 20%.

The hull was then completely sanded back to bare wood to remove all old varnish and paint layers. This process revealed the true condition of the wood and identified areas requiring structural repair. Thorough dust removal was carried out using an industrial vacuum cleaner to ensure a perfectly clean surface ready to receive the resin.

Step 2: Filling cavities

Once the hull was perfectly clean, structural repairs were carried out.

Corroded copper rivets were removed one by one and replaced with new copper rivets. Cracks and gaps between planks were filled with epoxy resin thickened with Mixfill 10.

To prepare the mixture, WOODPOXY PLUS resin was mixed with WOODPOXY MEDIUM PLUS hardener at a ratio of 2:1 by volume (or 100:42 by weight). Once the resin and hardener were blended, Mixfill 10 was gradually added in a fine, rain-like motion to achieve a smooth, homogeneous texture.

Step 3: Hull impregnation

After repairs, an impregnation coat was applied over the entire hull.

WOODPOXY PLUS resin mixed with WOODPOXY SLOW PLUS hardener was applied with a brush to fully saturate the wood. This step reinforces the wood deep down while improving adhesion of the fiberglass fabrics during lamination.

Step 4: Hull lamination

Once the hull was properly impregnated, lamination was carried out using fiberglass fabric impregnated with the WOODPOXY SLOW PLUS epoxy system.

The process began with the rabbet area (the junction between keel and planking), a zone subject to high mechanical stress. Two strips of BX 450 g/m² fiberglass were applied: one 100 mm wide strip followed by a 200 mm strip to ensure optimal coverage. The fabrics were generously impregnated with resin, and all air bubbles were removed using a laminating roller.

The hull bottom was then laminated with two layers of BX 600 g/m² fiberglass. The hull was divided into sections corresponding to the fabric roll width (1.25 m). Fabric placement was oriented at 90° to the keel axis to optimise structural strength.

The first layer was applied plank by plank, starting at the centreline. Once in place, a second layer was applied with staggered overlaps to ensure uniform coverage and avoid weak points. Resin was applied using rollers and brushes, ensuring the fabric was fully saturated.

Step 5: Application of the fairing compound

After lamination, the hull was coated with an epoxy fairing compound made using the WOODPOXY PLUS system and Mixfill 10.

The mixture was prepared at a precise ratio of 2:1 by volume (or 100:42 by weight), with Mixfill 10 gradually added while mixing carefully to prevent clumping.

The compound was applied with a wide spatula to obtain a perfectly smooth surface. This layer fills small irregularities and provides an immaculate finish before primer application.

Step 6: Application of epoxy primer

To reinforce watertightness and ensure proper adhesion of antifouling paint, two coats of Epoxyguard IM409 epoxy primer (Map Yachting) were applied with a roller.

The recommended drying time between coats was respected to allow full curing. This primer forms a watertight barrier and provides excellent adhesion for antifouling coatings.

Step 7: Antifouling application

The final step was the application of antifouling, essential for protecting the hull against marine organism growth.

A first coat of hard-matrix antifouling was applied to provide a solid, abrasion-resistant base. A second coat of erodible Teflon-based antifouling was then applied to improve water flow and limit fouling.

Practical tips for successful lamination

• Work in a stable temperature environment (ideally around 18°C).

• Plan a team of four people.

• If the resin is too fluid on vertical surfaces, add colloidal silica to increase thixotropy.

• If the open time is short, work in sections to prevent resin from curing before the next fabric layer is applied.

Why choose the WOODPOXY PLUS epoxy system?

The WOODPOXY PLUS system offers excellent wood impregnation, high mechanical strength, and ideal flexibility for marine applications. Combined with BX 600 g/m² fiberglass fabric, it creates a robust, stable, and perfectly watertight hull.

Conclusion

Laminating a wooden boat with a suitable epoxy resin not only reinforces the boat’s structure, but also extends its lifespan and improves its performance at sea. Thanks to the WOODPOXY PLUS system and high-quality BX fiberglass fabrics, your boat can regain a second youth and perfect watertightness.