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EPOXY, CARBON, PREPREG – the secrets of the magic boat building potion explained

This magic potion is a potion not brewed by the druid Getafix, but it gives supernatural powers to yachts. And even better than the original which is brewed from various herbs, the AEOLOS potion gives supernatural powers for an unlimited time. Do you like ... ... winning races or fast trips? ... low energy consumption due to low weight?

... more safety thanks strong keel/hull? ... to have never problems with osmosis? ... to support sustainable yacht production? Check out our revolutionary mixtures of ingredients for yacht production!


The main ingredients are

- Carbon - Epoxy - Prepregs

- Sandwich materials

!! The recipe of each yachts is

optimized by our engineers and brewed

with a big portion of AEOLOS teamwork. !! With the following text and images we explain some of the ingredients and their effects:

Carbon Unidirectional – The king of the fibres

Unidirectional carbon fibre is a real asset: because the fibre can be placed exactly in the direction of force, it offers enormous potential for increasing strength and durability while reducing weight. In addition, unidirectional fibre is again much stronger (typically twice as strong) than woven fibre because the tensile potential is much higher at only a fraction of the weight density. In woven materials the fibre makes curves, which means that it is more flexible. UD fibre does not bend when subjected to force - it lies flat. Flexibility is as important as strength. In unidirectional fibres, you can overlap them at different angles and orientations to maximise strength in different areas while keeping the fabric stiff and stable.

CARBON - light weight

- huge tensile strength


Epoxy Resin is highly adhesive and durable resin. Epoxy resin, when used with carbon fibre to create incredibly strong, rigid and lightweight structures. Epoxy has great mechanical properties, far better than polyester resin: - bonding strength of up to 2,000 psi

- great flexural strength

- moisture resistant, no osmosis

- very resistant to wear, cracking, peeling, corrosion and damage from chemical and environmental degradation

- no shrink when cured.

- less emissions

Laminate Hardness Test Meter Digital Durometer (Shore) at AEOLOS/NOVA


Prepregs are pre-impregnated fibres, the fibre comes together with the resin. That means that as little resin as necessary is used in the hull. With prepreg technology 55% to 70% fibres/resin by weight, while the desired or nominal resin contents for these materials are 31% resin content for unidirectional carbon prepregs and 35% resin content for woven cloth carbon prepregs. With glass fibres the fibre content can be bigger, because the fibres are heavier than carbon.

Typical fibre/resin contents by weight

Handlamination: 30%-40% (depends a lot on the craftsman)

Handlamination with vacuum pressing: 40%-50% (depends a lot on the craftsman)

Infusion: 45-55% (depends on the preparation and craftsman)

Prepreg: 55-70% (low tolerances, defined process)

The fibers provide the strength of the laminate, the more the better!

But our prepregs are more than just fibres with resin, we developed a complete system for an optimal production process: - Fibre Prepreg (Carbon, Glass, Basalt, Flachs, ...)

- Glue Film

- Surface resin The new NOTUS NE7 prepreg system is developed by our sister company NOTUS Composites, also based in the UAE. The novel low-temperature curing chemistry offers significant cost advantages and allowed us to switch from the infusion lamination process without developing expensive new high-temperature tooling.

NE7 prepregs can be cured at temperatures as low as 70˚C, with the standard cure cycle being 12 hours at 70˚C, matching the typical cycle time for an infused part with a component Tg of 85˚C. NE7 materials have a good outlife of 30 days at 20˚C and are available with unidirectional, multiaxial and woven reinforcements. NE7 can also be supplied as a resin film.

As we know. we are the only shipyard in the world that develops and manufactures its own prepregs. We produce up to 100,000 sqm of prepregs per month, so we have unique conditions and possibilities. The overall production cost is similar to or even lower than vacuum infusion due to cost savings in the shop during application and cleaning, less waste and lower health and safety costs. We are using the system for all AEOLOS yachts and the AEOLOS Flying Dutchman.

In addition to the prepregs, we have developed a resin film that we insert between the fibres- and the foam. We call it "Glue Film". Is not only about weight. The reliability of the connection foam fibres and the surface is tricky. We test how much is needed for each foam type in the laboratory. This means that the actual laminate can have even less resin content.

• more weight, more resin in the prepreg fibres • danger of air pockets and weak connection to the foam core

• minimal resign in the prepreg fibres • perfect bonding of the core, due to exactly tested additional resin

• no air pockets on the foam

Test: Perfect connection to the foam.

For the surface we use a special epoxy resin, also developed by us (our sister company Notus Composites), which reduces the grinding to almost zero.

Our surface resin (brown) for prepreg is perfect bonded to the fibres. Polyester-Gelcoat is not recommended with the use of prepregs, can cause delamination, because the Polyester gelcoat cures far faster than the prepreg and will not bond properly. The Notus surface resin is based on the same Epoxy system used in the prepregs. During curing in the oven it become sticky again and bonds to the prepreg. Based on this superstrong "filler" it is easy to paint. We prefer ALEXSEAL paint, this coating provides far longer a glossy surface than a traditional gelcoat, is UV-resistant and it saves again a lot of weight. A metallic effect is not possible with polyester gelcoat, red, blue or black gelcoat is fading away with the UV of the sun. Anti-slip protectin can be easily added with paint, a huge safety factor.

Sandwich materials

The core in a sandwich composite serves the same function as the web of an I beam. An I beam is to bear the shear force, while the two flanges, separated by the web, provide the bending rigidity. The objective of the sandwich composite is to offer a structure that is strong and stiff but at the same time lightweight.

The major advantages of sandwich composites:

- low overall density

- high strength-to-weight ratio

- high stiffness-to-weight ratio

- uniform energy absorption capacity

- good thermal and acoustical insulation

A simple, visual test of a 200g light piece of carbon prepreg sandwich with PVC foam


Normally in cooking you would believe too many cooks spoil the broth, said when there are too many people involved in trying to do the same thing, so that the final result will not be good. But if you mix competences and uses their strengths it become even better.

We joined a great team and would like to bake your boat in our oven.

By the way: Our design team has a dedicated process in brewing a great boat. Check out in this article >>

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