Home / Guest Author / Materials & Applications / “he’e nalu” – Surfing on Waves Thanks to High-quality Materials

“he’e nalu” – Surfing on Waves Thanks to High-quality Materials

Surfing and kite surfing, with the new stand-up paddling, have become in recent years the most popular on-water board sports.

“heʻe nalu” in Hawaiian means gliding on the wave, and so it might have been the impression of the Europeans who first saw Tahitian surfers in 1777. For the Polynesian tribes, being able to ride a wave was so important that the best surfer was also the head of the community. Similar respect and spirituality were given to the Hawaiian surfers.

From the first traditional Hawaiian “papa he’e nalu” surfboards that were made from cedar or redwood and weighed over 60 kilograms, the evolution of materials allowed for lightening of the boards, giving the users better control and manageability.

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Surfboard

The most famous on-water board, surfing, is a combination of balance, force and elegance. The surfboards come in different sizes (longboards and shortboards) and shapes (number of fins, shape of the prow…), depending on their utilization, the size of the waves, and the level and anthropometrics of the surfer (Figure 1) [1].

Figure 1. Different surfboards [1].

Based on the necessary properties and characteristics, the materials constituting a surfboard range from polystyrene to polyester and fiberglass [2] (Figure 2). In general, the most common materials are the following:

  • Polystyrene foam (extruded and expanded) is a common lightweight material for the core of the surfboards. Polystyrene, especially in the form of expanded polystyrene (EPS), has been recently used with 90% of its volume occupied by oxygen. EPS is extremely lightweight, easy to manoeuvre and more floatable than other polystyrene foams; however, it is very difficult to shape and mold [3]. Polystyrene extruded cores have a closed-cell structure. Consequently, they respond better under pressure and so are used by advanced surfers.
  • Polyurethane gives more flexibility and durability. It was frequently used for the board core in the period after the 1950s, but it turned out to be a toxic material, which led to the development of alternative materials [3].
  • Polyester (silma resin and UV H61) and epoxy resin are used to make up about 80% of today’s boards on the market. With a cover, the board becomes stronger, more flexible, and waterproof.
  • Fiberglass gives rigidity and strength to the board at a cheaper price than carbon fiber.
Figure 2. Scheme of the different layers constituting the surfboard [4].

The layers of materials mentioned above allow the use of the board in any kind of situation and for different applications, such as stand-up paddle – SUP (called in Hawaiian Hoe he’e nalu).

Stand-up paddle originated in Hawaii, where surf instructors were in search of a way to follow their surfers while teaching. Standing on the surfboard while using a paddle, they could get closer to their students and give them suggestions. The paddle used in SUP is generally made from aluminum, fiberglass, carbon fiber, or Kevlar.

In addition to all that, in the back part of the board we find the traction pad and the fins. 

The traction pad is made of different types of rubber and permits the surfer to grip well to their board and pivot effectively [3].

The fins of longboards are frequently glassed with the rest of the board, i.e. the board and the fins are covered by the same layer of fiberglass.

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Kitesurfing, water skiing and windsurfing

The boards utilized in water skiing, kite- and windsurfing are, similarly to other surfboards, made from polyester, carbon fiber, Kevlar and other materials like foam and wood.

The kite faced a great evolution in the last twenty years, becoming lighter, safer to guide, more air resistant.

The majority of the kites are not made from nylon but rather from polyester (particularly purified terephthalic acid (PTA) or its dimethyl ester dimethyl terephthalate (DMT) and monoethylene glycol (MEG)), owing to its higher resistance to ultraviolet (UV) rays. 

However, since the kite also needs to be airtight, a more rigid structure is needed.

Therefore, kites are reinforced with materials such as cuben fiber (CTF3) – also known as Dyneema Composite Fiber (DCF) – mylar, dacron DP175, high-tenacity dacron, thermoplastic polyurethane (TPU), ballistic kevlar, and neoprene [5].

Figure 3. A kite surfer [6].

The sails utilized in windsurf are made of a monofilm (clear polyester film), dacron (woven polyester) or mylar, and some parts can be reinforced by Kevlar (Figure 4).

Figure 4. A windsurfer [7].

The future

Many companies are trying to constitute on-water sports boards using recycled materials, such as lumber, which is eco-friendly and cost-efficient.

Taking into consideration the eco-friendly point of view, temperature sensors and GPS have been oftentimes placed on the surfboards in order to track the conditions of the water around the coasts during surfing [8]. 

Recently, many improvements to surfboards inspired by nature have been proposed. For instance, in a recent study, researchers proposed shortboard surfing fins that were inspired by the fins of the humpback whale as they exhibited better fluid dynamics and better surfing performance [9]. 

Moreover, alongside the commonly used honeycomb structure, different bio-inspired core structure designs have been tested in order to not only increase the resistance of the boards but also their safety. 

Such designs, such as the spider web, the pinecone, and the carbon atom configuration, produced mainly through 3D-printing technologies, can help reduce the production costs, as well (Figure 5) [10]. 

Figure 5. (a) A pinecone design with two 8-number and 13-number opposite directional spirals; (b) Sunflower with Fibonacci spiral; (c) Pinecone-inspired structure designed using Fibonacci spiral [10].
Veronica Bessone

Veronica Bessone

"I am fascinated by how the development of new sports equipment allows pushing the boundaries of human limits further, reaching new records."

References

  1. https://www.secondhandboards.com/blog/7-types-of%20surfboard-shape-you-need-to-know-about Accessed on 30th May 2020
  2. https://www.singlequiver.com/enelpico/en/different-types-of-surfboard-materials/ Accessed on 30th April 2020
  3. https://www.surfingfeed.com/how-is-a-surfboard-made/ Accessed on 25th May 2020
  4. https://surfshopsaustralia.com.au/nsp-surfboard-construction/ Accessed on 30th April 2020
  5. https://www.surfertoday.com/kiteboarding/what-are-kitesurfing-kites-made-of Accessed on 4th May 2020
  6. https://www.surfertoday.com/kiteboarding/what-are-kitesurfing-kites-made-of Accessed on 30th April 2020
  7. https://www.harry-nass.com/en/windsurfing-hurghada/ Accessed on 30th April 2020
  8. Brewin RJ, de Mora L, Jackson T, Brewin TG, Shutler J. On the Potential of Surfers to Monitor Environmental Indicators in the Coastal Zone [published correction appears in PLoS One. 2016;11(9):e0162591]. PLoS One. 2015;10(7):e0127706. Published 2015 Jul 8. doi:10.1371/journal.pone.0127706
  9. Shormann DE, In Het Panhuis M. Performance evaluation of humpback whale-inspired shortboard surfing fins based on ocean wave fieldwork. PLoS One. 2020;15(4):e0232035. Published 2020 Apr 21. doi:10.1371/journal.pone.0232035
  10. Soltani, A., Noroozi, R., Bodaghi, M., Zolfagharian, A., & Hedayati, R. (2020). 3D Printing On-Water Sports Boards with Bio-Inspired Core Designs. Polymers, 12(1), 250. https://doi.org/10.3390/polym12010250

 

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