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An expanded-polystyrene-free float

Wenco was a market pioneer in introducing blow molded pontoon platform floats that did not have to be filled with expanded polystyrene.

Floats are an indispensable component of the rafts or floating structures used in productive work. They are widely used in salmon farming, for example, as they support the cages where the fish live.

Historically, these floats were made using a technology that had been in use since the 1940s, known as rotational molding, which consists of heating the outside of a mold that contains the polymers to be melted inside. To prevent the floats from failing, once manufactured they were filled with expanded polystyrene (EPS), also known as “plumavit” in Chile.

The problem with these kinds of floats, used for decades in aquaculture, is that sooner or later they would break and there was no reasonable way to dispose of them, because recycling the plastic and the EPS required them to be mechanically separated which is a tremendously expensive process. As a result, the float waste could end up being dumped anywhere and would begin to release EPS beads that would pollute the land and especially the ocean.

In 2011, following a three years development effort, which included the failure of two prototypes, Wenco introduced the 506 and 580-liter pontoon platform floats manufactured using a blow molding technique. These floats no longer needed to be filled with EPS, but rather only had to be filled with air using a valve similar to that of a tire.

This type of float, which today holds five patents, is 47% lighter than a rotationally molded one, floats 3% better per liter of displaced water, uses 47% less plastic material, and is 68% more resistant to impacts and flexion. In addition, it is one hundred percent recyclable. Plus, unlike rotational molding, blow molding does not require fire which results in an enormously reduced final carbon footprint. In short, the new float was a better solution not only for the aquaculture industry but also for the environment.

The biggest difficulty was introducing the new float into the market, as salmon companies were initially reluctant to use an EPS-free float. But the testing carried out on land, as well as its use in the water -where these floats have been in use for over five years- gave proof of its safety, durability, and reliability.

One of the most convincing tests for customers at the time was a strength test, recorded and shown in the video below. The metal passageway used, typical of salmon pontoon rafts, weighed 490 kilos, the float 16 kilos, and the parts holding the float 8 kilos, for a total weight of 514 kilos. The video, despite being a low quality recording, speaks for itself.


The strength test was repeated with the new 1,800-liter version of the float, developed by Wenco Sur in 2019, which is three times larger than the previous one. The weight of the passageway this time was 1,065 kilos, to which was added the weight of the float, 40 kilos, and the weight of the parts holding the float, 16 kilos, for a total weight of 1,121 kilos. As in the previous video, the drop height was not measured for safety reasons, but given that the passageway is approximately 10 meters long, its angle allows us to estimate that the drop was between 6 and 7 meters.


Today the EPS-free float is the standard in the salmon industry. The competition have developed their own versions, but as they are imperfect copies they do not offer all of the advantages of the models patented by Wenco.

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