Seaweed Surfboards: Innovating With An Invasive Species

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Approximately 100 miles off the southern UK coast lies Jersey Island. It has the surf break that is the British Isles’ southernmost. The break stretches 5km along St. Ouen’s Beach on the western coast. Charlie Cadin is among the surfers frequenting the area. However, an invasive seaweed species had cropped up, throwing the natural off-balance. So Cadin dealt with it using his expertise: make seaweed surfboards.

Holidaymakers and tourists usually cover the area during the summer. But in winter, it is usually empty except for the surfers. The island faces a concerning problem between May and September. The beach gets entirely covered by Sea Lettuce, an invasive seaweed species. The seagrass in the locality gets covered as well, disrupting the bay ecosystem. Moreover, with the retreating tide, the seaweed dries. This produces a gas known as Hydrogen-Sulphide. The gas is known for causing injuries during seaweed disposal in France.

Charlie Cadin had seen his huge problem as well as what was being done to tackle it. So he wanted to turn it into something positive and constructive. He knew of the current attempts to make biofuel out of seaweed which is still too complex. He also has experience shaping surfboards and knew the amount of wastage in the process. So he attempted to make a seaweed surfboard: build up the board rather than carving a block down.

Surfing The Waves Using Seaweed

97% of the present surfboards use polyurethane foam as their core material. This is a petrochemical product and thus not sustainable at all. Nearly 250kg of CO2 is produced per normal surfboard. It would take 4 decades for one tree to offset that. Using the seaweed called Sea Lettuce thus gets rid of all the harmful foam. At the same time, it has just as much fiberglass as usual surfboards.

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So Cadin collected nearly 45kg worth of seaweed from the mark for low tide. He then washed it through fresh water and then dried it across a rocker mold. More material was piled on and then compressed. This resulted in a material similar to paper-mache. Cadin then cut out the skeleton, bottom, deck, and rails from the sheets. Everything was fit together in slots and stuck together to the surfboard’s bottom sheet. The ribs’ top was curved so that the deck is convex. Rails were fitted and strapped as well.

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As the seaweed dried, its color became translucent-white looking like the stained glass windows. Finally, the board underwent the process of glassing similar to normal surfboards to prevent it from dissolving in water.

The Final Board Is Well On The Way

The completed board weighed 4.2kg and had dimensions of 6’4”, 21”, and 2.3/4”. The board’s subtle concave turns into a vee at the tail with soft tails becoming hard. The surfboard is as smooth as any other. Cadin says that the board had exceeded expectations during the tests. Its added half-kilo weight adds to its drive in the sea. It has an extremely high volume. Moreover, the material is naturally buoyant because it is filled with air. Paddling the board was nice. However, Cadin admitted that the panel made of sea lettuce became a bit warped and uneven.


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A post shared by Charlie Cadin (@charlie.cadin)

Cadin is currently a student of Marine engineering at the University of Plymouth. He came back during his break on Christmas and tried to use seaweed once more. This time he tried to increase its economic viability. So after collecting buckets of it, he laid it flat for drying. Then it was crushed to form a powder. With some chemicals, a material having identical density to foam was created. This foam blank is still being tested. However, Cadin is certain that a machine for CNC can use this blank made of seaweed.

Image Credits: Charlie Cadin

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