Innovations in Sustainable Yacht Propulsion

An experimental hydrofoil boat featuring a CFRP hull and propelled by hydrogen and solar power will be sailing the waters off the coast of Monte Carlo this July. The Sao Gabriel 01 (SG01) will participate in the Monaco Energy Boat Challenge, which fosters development of sustainable propulsion technologies that could speed up yachting’s transition to non-fossil fuels.

The SG01 is included in the Challenge’s SeaLab Class, which is focused on zero-emission propulsion systems or green methanol with carbon capture. During the event, the boat will take part in a speed test and an endurance race.

“The hydrofoil design is almost a must for boats in this class, as it dramatically reduces drag and allows the team to be as efficient as possible with their zero-emission drive systems,” says Eduard Galofre, CEO of Mel Composites in Spain. “The vessels must be lightweight, stiff and strong, which means carbon fiber construction is a key enabler.”

The Energy Boat Challenge is intended to be a learning experience for participants, with teams of students, universities, technical colleges and industry professionals working together throughout the year on their entries. The 26.2-foot long SG01 was built by Portugal-based Técnico Solar Boat (TSB), a student-led team from Instituto Superior Técnico. Mel Composites provided materials and served as technical adviser for the boat’s hull.

“The TSB team created the design and then we advised on materials and helped them create a foolproof infusion strategy,” says Galofre. The hull features Sicomin InfuGreen 810 low-viscosity epoxy resin, which is formulated with 38% bio-based carbons.

“The client was very keen to minimize the impact of the entire vessel, so a sustainable, bio-based epoxy was definitely important to work alongside the clean energy sources like solar and hydrogen,” says Galofre.

Using material test samples produced by Mel Composites, the TSB team performed tensile, compression and flexural testing in the laboratory to verify them against the hull’s design data. Mel then worked alongside and advised TSB on the infusion process.It ensured the mold surface was in excellent condition, that it sealed perfectly and that it provided an air-tight surface for the infusion.

“We make sure all materials and consumables have been fully tested and perform well in the exact laminate we are building,” says Galofre. “Doing this, and using a standard set of consumables from Compoflex, allows us to reduce lay-up time and minimize wastage throughout the build.” 

After coating the mold with a release agent, the team applied the outer carbon fiber skin in the mold before placing the foam core layers on top. They added the inner skin, then a top layer that combines peel ply, perforated film and infusion mesh in a single product. They placed resin distribution channels and spiral tubes to ensure the resin would flow consistently. The final step was sealing the vacuum bag on top of the laminate stack. The SG01 hull was infused in less than an hour.

“By carefully controlling the resin process, we ensured that we minimize resin content and created perfect quality laminates with no excess weight added,” says Galofre.

Lightweighting was not the only consideration for the hull design. “It was important for the TSB team to ensure that the internal structure is well bonded and that foil bearings are well supported,” says Galofre. Although the loads are not as high once a boat is up and foiling, designers have to consider what happens if a boat drops off the hydrofoil or crashes down at high speed.

The construction of vessels like the SG01 is important for both the boating and composites industries.

“Working with a student team is a great opportunity for Mel Composites to help pass on our technical knowledge to the next generation of composite engineers and manufacturers,” says Galofre. “It is massively rewarding for us, and it really supports the composite industry.”

Opening image: Student workers from Técnico Solar Boat (TSB) vacuum infused the SG01 hull.

Photo credit: Mel Composites