Monocoque Structural Laminate (MSL) fusion construction is the industry leader when it comes to manufacturing process. It is used as the construction method of choice for Cottage Sports premium inflatable stand up paddle boards.
Basic single layer boards are made by hand applying a layer of soft PVC to coat the drop stitch core. This construction is generally seen in lower end boards. Due to only relying on one layer of soft PVC to keep the drop stitching core airtight, they can be less durable. Single layer boards will also have more flex to them.
Double layer boards are made by gluing an additional layer of more rigid PVC on top of that first layer, coating the entire paddle board a second time. This results in a board that is far more rigid and durable, however much heavier. It also can introduce air pockets and cosmetic flaws during the gluing process and is vulnerable to delamination as the adhesives break down.
Why MSL Fusion:
MSL fusion does away with hand applying the first layer of soft PVC. Instead, the drop stitch core is covered in a strong adhesive to act as the first layer. That is followed by a second layer of strong rigid PVC. It is machine laminated and fused onto the board. This eliminates any potential imperfections of the hand gluing process and gives the board a perfect cosmetic finish and look. The rigidity, strength and durability is drastically increased and at the same time the board is kept far lighter by using the machine lamination and eliminating the need to first coat the board in a soft layer of PVC.