Why do some stripes appears on the slick of our bodyboard?

The slick of our bodyboards, the side in contact with the water, is usually marked with stripes, generating frustration for many bodyboarders. But those stripes are normal, and we will explain in this article why they appear.

Our bodyboards are composed of several materials, with different mechanical properties. The core of the board is composed of a polyethylene (PE) or polypropylene (PP) foam. This material is quite elastic, flex easily and returns to its original shape. It has a high elastic limit, it can be deformed a lot and return to its original state without any consequence.

This is an issue, because we need that our bodyboard have certain rigidity. This is why the bodyboard carry a stringer, a fiberglass or carbon tube located in the middle of the core of the board, which gives more rigidity to the board. The board still flex, but the flex is limited by the stringer.

The core of our bodyboards has another problem, its surface is porous and does not offer an optimal slip with the water. This is why our bodyboards have a slick sticked to the bottom of the board. This slick is composed of a very thin plastic layer, less than 1mm thick, quite hard and perfectly smooth. It offers very little resistance to water, and for this reason it is used, so that our boards slide perfectly without offering resistance to water.

But this slick has less capacity of deformation than the core of the board, this material have a limit of elastic deformation much lower than the core of PE or PP. But both parts, the core and the slick are sticked together, they form a single piece, which mean that when the bodyboard flexes, both materials flex. If the deformation of the bodyboard is too important for the slick, the deformation of the slick exceeds its elastic limit, it goes into plastic deformation, which mean that it deforms but does not return to its original state, and that´s when the famous line in the slick of the board appear. The core of the bodyboard, having a very high elastic limit, returns to its original state without being affected.

These stripes appear with the use of the bodyboard, they can appear even after a few days of use. It is normal, and it contributes to the flex of the board. It does not harm at all your bodyboard, it happens to everyone, even the pro. If you look closely at picture of the podiums of the APB championships, or in the photos of the pro, you can see that their bodyboard also have this type of stripes in the slick, as you can see in those photos of Amaury Lavernhe and Ian Campbell.

No Bodyboard brand changes a board because of those stripes, even if it appears after three days of use. It is normal in the life of the bodyboard, it is not a manufacturing defect.

We hope that this article will allow you to better understand how our body boards work, the materials that compose it, why they are used, and why you should not stress with those stripes that appear on your bodyboard!