Yamarin Cross concept boat: Exploring flax fiber and recycled materials in boat manufacturing

As part of a collaboration between Inha Works Ltd, manufacturer of Yamarin, Yamarin Cross, and Buster boats, and EKA Composite, the company responsible for lamination and assembling of the boats, tests more sustainable materials in this concept boat. The model is based on the popular Yamarin Cross 62 BR, and its structure incorporates:

•  Recycled aluminum 
•  Flax fiber as a structural reinforcement 
•  Recycled PET plastic from used bottles

"Together with EKA Composite, we want to demonstrate that natural fibers and recycled materials can be used in boat manufacturing not only in an economically viable way but also to create stylish, high-quality boats," says Artturi Niittynen, Sales & Marketing Director at Inha Works.

The deck, manufactured with 100% Flax fibers instead of traditional fiberglass, for the Yamarin Cross 62 BR Concept Boat are manufactured in Finland by EKA Composite, while the aluminum hull is produced at Buster Boats' factory. Depending on the batch, 30–70% of the aluminum plates used in the boats come from recycled material.

• The concept boat will be on display at the Helsinki International Boat Show from February 7–16 at Booth 6 d 48.

Niittynen emphasizes that researching new materials and production methods is a key part of the company's development work. Yamaha Motor Corporation, the parent company of Inha Works Ltd, has committed to achieving carbon-neutral production by 2035, and these advancements support that goal.

"During this decade, we are working towards that target by minimizing energy consumption and transitioning to carbon-neutral and renewable energy sources," Niittynen explains.

The Inha Works Ltd and EKA Composite project will continue, with further details to be shared in spring and summer. The new materials will be tested during the upcoming boating season, and a commercial launch decision will be made based on testing and market feedback.

Flax Fiber Replaces Fiberglass in the Concept Boat

Traditional fiberglass boats are made using a composite structure, where fiberglass reinforcement is bonded together with polyester resin. In this concept boat, flax fiber fabric replaces the fiberglass reinforcement, significantly reducing environmental impact.

• 55% lower CO₂ emissions compared to fiberglass manufacturing (Source: Saertex)
• Lighter weight – Flax fiber composite weighs 1.5 g/cm³, compared to 2.54 g/cm³ for fiberglass
• Excellent mechanical strength – Long flax fibers (up to 90 cm) ensure high durability

"A portion of the boat's deck has been painted with a clear see-through gelcoat to highlight the beautiful, natural texture of the flax fiber," says Henna Forsström, Procurement Manager at EKA Composite.

Flax fiber not only enhances the boat’s aesthetics but also reduces weight. As a natural material, flax fiber has not yet been widely used in serial production of boats, but it has significant potential to partially or even completely replace fiberglass.

"Flax fiber is comfortable to handle in production and technically well-suited for boat components. The long fibers give it excellent mechanical properties, making it suitable for demanding applications," Forsström adds.

Recycled PET bottles as core material

In standard fiberglass boat construction, PVC foam boards are commonly used as core stiffeners for flat surfaces, forming rigid sandwich structures in floors and decks. The concept boat replaces PVC foam with PET foam, a material made entirely from recycled PET plastic bottles.

Additionally, the polyester resin used in the boat’s structure incorporates 22% recycled PET, further reducing the use of virgin fossil-based materials.

Lowering VOC Eemissions with advanced gelcoat

The gelcoat, which forms the outermost protective layer of the boat, is another area where improvements are being made. The Maxguard NP gelcoat, used in the concept boat, offers: 

• Up to 50% reduction in volatile organic compound (VOC) emissions
•  10–15% material savings compared to traditional gelcoats
• Increased durability, high UV resistance, and excellent blister resistance

"The new gelcoat not only reduces emissions but also provides an exceptionally hard, stylish surface with superior resistance to marine conditions," Forsström explains.

Vacuum Infusion: Reducing waste and emissions

Beyond sustainable materials, the concept boat's production efficiency has been improved through vacuum infusion technology. This manufacturing method: 

• Uses less material, creating a lighter and stiffer structure
• Eliminates styrene emissions during resin infusion
• Ensures better quality control and precision in boat building

“While deck lamination is just one part of manufacturing for Yamarin Cross, for us at EKA Composite, lamination is a core process that we continuously strive to improve in quality and environmental impact,” says Mikael Strand, CEO of EKA Composite.

The concept boat also includes Cork flooring – A renewable, non-slip, and comfortable material underfoot and Spradling Linetex fabric for upholstery – Produced by a carbon-neutral and ISO 14001-certified manufacturer using a closed water loop system

Industry collaboration for a sustainable future

Inha Works Ltd is also participating in the FurBio project, led by the University of Oulu, which explores the use of furfural, a byproduct of industrial side streams, as a raw material in resin production.

Furthermore, the EKA Composite concept boat project is part of the “Green Transition of Vacuum Infusion Process” project led by EKA Composite, which has received support from Finland’s ELY Centre and partial EU funding.

Towards carbon-neutral boat manufacturing

This project is part of a broader strategy within Yamaha Motor Corporation to achieve carbon-neutral production by 2035. Over the next decade, Inha Works Ltd will:  Reduce energy consumption  Transition to carbon-neutral and renewable energy sources

The initiative represents a step forward in sustainable boat building, and real-world testing during the 2025 boating season will determine the potential for commercial production.