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The cork decking

The subject of deck coverings is an area where many alternatives have flourished in recent years: synthetic deck covering, iroko, adhesive foam, etc.

In our search for ecological and sustainable solutions for the Excess catamarans range, and after testing a prototype of a hybrid diesel-electric drivetrain aboard an Excess 15 (see our articles on the subject in the E’Lab), we decided to go with the opinion of the greatest number of people - cork decking.

At the International Multihull Show, we exhibited an Excess 12 that featured a sugarscoop fitted with SEACORK decking. We’re interested to hear your feedback on this technology.

Cork is an ecologically responsible product. Its longevity is an important asset to reduce excessive consumption, but it is also a solution involving local production, thus avoiding lengthy transport problems. It comes from the bark of trees grown on the shores of the Western Mediterranean and processed in France not far from our shipyards. Cork Oak bark is harvested every 9 years and is naturally renewed without the need to cut down the tree. A single tree can provide 10 to 12 harvests, while absorbing large amounts of CO2, which makes it a sustainable development material par excellence.

But let’s take a look at the great advantages of a cork deck, of which there are many for us boaters.  

First of all, it is an excellent non-slip material. Its micro-abrasive texture and its flexibility promote adherence and safety in all circumstances, even when covered with water. 

Comfort, above and below decks, is its second great quality. It won’t burn your feet in the sun, and it cushions your body weight as you move around for a comfortable ride on deck. Its softness and suppleness allow you to be on your knees or to sit down in comfort. Down below, its acoustic and thermal insulation qualities reduce noise and temperature. Footsteps or falling objects no longer wake those off watch. The inside temperature on board decreases in the areas under the parts covered with cork.

Aesthetically, like other natural decking materials, it turns gray over time, and a simple sanding can restore it to its original brown color. Impervious to watery and greasy liquids, it will resist the most tenacious of stains. It is rot-proof, so maintenance is easy, and it has a very long life.

On the technical side, its compressibility and elasticity, with total resilience, make it a material that’s perfectly suited to the maritime environment – one that can cause other deck covering materials to expand, shrink or puncture. Half the weight of teak or some synthetic coverings, it contributes to weight savings and maintaining good performance.

For safety, its high self-extinguishing resistance allows to delay fire. Anti-conductive, it is an excellent electrical insulator in the event of a lightning strike. And from a sanitary viewpoint, its natural anti-viral, anti-microbial and anti-static properties offer an undeniable plus, especially when sailing in tropical regions.

Cork does however have some disadvantages. First, it has a different aesthetic than traditional woods, and so might be perceived as less noble. Although locally grown, it also remains an expensive product and it isn’t cheaper than exotic woods. Finally, its great capacity of expansion, before gluing, makes it a more difficult material to manage during its installation.

User reaction

In order to carry out a proper test at the show at La Grande-Motte, we placed 70-millimeter-wide strips, without a surround, with gray caulking in the seams, on an Excess 12 and asked our dealers to give us feedback. About 70% of the boaters found the cork convincing, but it's worth noting that those who stepped on it were far more enthusiastic than those who only looked at it.

The questions we’re asking:

There are several different designs of cork decking. We'd like to know your preferences for the features below.

Would you prefer a more conventional 44-millimeter-wide strips, or a 70-millimeter-wide strip as shown above?

We have used gray caulking on the Excess 12, but would you prefer black caulking? 

In your opinion, is it better to have deck planks with or without a surround?

More generally, do you feel that cork is a solution in line with the Excess DNA?

One final question, and it’s far from the least important! Would you buy a boat with cork decking?

We thank you in advance for your answers in the comments and are looking forward to discussing this topic with you.

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September 30, 2022
Looking at the list of advantages, cork decking seems to be the perfect solution and matches the Excess DNA. It also seems to be easy to maintain which is a major asset as opposed to teak.
I reckon the 44mm with grey caulking looks more refined and I believe a surround would finish it well.
September 29, 2022
Cork decking is a unique way to express the DNA of excess and the 70mm strips with no surround displays cork as a sustainable alternative as an option more than a replacement to teak. Personally I am turned away by boats with teak despite the aesthetics as it adds weight to the boat and is extra maintenance overall making teak an expensive extra which tries to replace fibreglass non-slip which works perfectly fine let alone the fact that teak is unsustainable. Cork, being more sustainable still is not fully sustainable as cork farms create monocultures in farming (which do not provide a habitat for local species) and therefore I would unlikely prefer cork decking over just fibreglass non - slip.
Using cork as an insulator to noise and heat is useful about cork but a large volume of cork would be needed to effectively insulate - insulation is however and issue that should be looked into more as many boats (generally after a certain number of years) become noisy, excessively hot/cold and often damp in colder climates.
In summary, cork decking is a unique concept for those who seek an alternative decking material than fibreglass and provides a sustainable image to the excess brand.
September 29, 2022
I like the 70mm strips no surround - got a modern fresh look.
Probably a valid Excess upgrade option -
But personally I would likely spend the weight on something else..
Enjoy catamaran
September 29, 2022
Bonjour Hervé,
Et tout d'abord encore merci de cette bonne idée: personnellement je suis d'accord avec la plupart des avantages / inconvénients listés dans le post en tout cas pour ceux que je connais et/ou imagine. Forcément je valide la démarche produit naturel, démarche durable, cycle court, caractéristiques mécaniques d'isolation et de poids, antidérapant, et j'aime bien l'esthétique et les sensations sous les pieds. Je me demande quand même comment cela vieilli, comment concrètement le liège réagit aux grosses tâches grasses (j'ai bien lu le post, mais cette matière semble couverte d'aspérités, voire poreuse, comment se gère le bidon d'huile moteur ouvert qui se renverse ...), comment ça résiste au "poinçonnage" : on pose un wing sur le pont et la pointe agressive du foil vient taper le revêtement, l'ensemble bouteille de plongée / stab qui bascule à la faveur d'une vague ... ? Sinon je suis séduit par ce revêtement et je préfère perso les bandes les plus larges, grises et sans contours... Mais les goûts et les couleurs :-) : nous sommes 2 à répondre et déjà 2 avis différents.
September 25, 2022
I would prefer 44 mm, black caulking , deckplank with a surround is looking more professionel, generall to put a decking on is not inline with the Excess DNA because of the weight and I wont` buy a boat with cork decking.