Freshwater Bay inflatable paddleboards (iSUPS) are made using Double Layer Fusion Technology. But how are inflatable paddleboards made, and what are the differences?
There are a few different methods of inflatable paddleboard construction, with each method having implications on strength, flex, weight and cost.
One thing all inflatable paddleboards (iSUPS) have in common, is that the internal core of the board is made of a drop-stitch material. Drop-stitch material consists of thousands of nylon threads that keep the deck of the board joined to the bottom of the board. Without these threads, the board wouldn’t keep its shape – it would just expand vertically as air is pumped in, until it reaches capacity and looks nothing like a paddleboard!
Although ALL inflatable boards are made using drop-stitch, not all drop-stitch is created equal. You can have linear drop-stitch, diagonal drop-stitch and V-shape drop-stitch. You also get different stitch densities – the higher the thread count, the more rigid the board, but the more expensive it is to manufacture. Many boards at the lower end of the market use drop-stitch with a very low thread count; usually around 5,000-7,000 threads per m2. At the core of a Freshwater Bay inflatable paddleboard is a German technology lightweight drop-stitch with 15,000 threads per m – up to 3 times higher than lower quality boards. This is the first step in improving rigidity as it can take higher pressure and there are more contact points tying the deck and the hull together.
Next we have the PVC layer, or layers.
1. Single Layer Construction
At the cheaper end of the spectrum, boards have a single layer of PVC. The molten PVC is poured over the drop-stitch base cloth to make it airtight. Job done! Except that quite often the board isn’t fully airtight and air can slowly escape through microscopic holes in the PVC. This could be fine for a while, but it’s not something we at Freshwater Bay Paddleboard Co would take a risk on!
Single layer boards are also prone to flex and are less durable than multi-layer construction boards. However, they are light weight and lower cost which is a bonus. The worst examples of this construction are the boards you can buy in supermarkets, which also tend to be very thin and poorly designed. A higher quality example of this construction from the main brands is the Fanatic Pure or Starboard Zen range.
2. Single Layer with Stringer Construction
Single layer with stringer is a step up from single layer. It’s the same single layer construction, but with the addition of an extra PVC strip glued along the middle of the board, from nose to tail. This doesn’t cover the whole deck or hull of the board, just a section running length-ways down the middle. It improves stiffness over the single layer boards, without adding too much weight. But the rest of the board is still single layer, and less durable. Although an improvement on the single layer board, it still has flex. An example of this construction is the Fanatic Fly Air.
3. Double Layer Construction
Double Layer Construction takes a single skin board and hand glues a second layer of PVC to it. These boards are 100% airtight, stiffer and more durable than single layer construction. This is how the original Freshwater Bay Paddleboards iSUPS were constructed back in 2015. They were stiff and rugged but heavier. This was still the best construction method available back then, but not perfect. Some brands still use this double layer construction, but we’ve moved on to something better!
4. Double Layer Fusion Construction
As mentioned at the start, Freshwater Bay Paddleboard Co inflatable SUPs are made using Double layer Fusion Technology, the highest construction quality possible. Instead of hand gluing a second layer of PVC to a single skin board, Double Layer Fusion Tech heat welds two layers of PVC together without needing the glue layer. The fused PVC layer is then heat bonded to the drop-stitch base with a sealing adhesive layer. This sealing adhesive layer not only forms the base to attach the PVC to the drop-stitch, but also creates the first airtight layer of the board.
This is all done in controlled conditions, before the shape of the board has even been cut. This is very similar to the Red Paddle MSL Technology, and the same that is used in the Fanatic Premium range.
Once the shape of the board has been machine cut, the first 0.9mm layer of PVC rail is heat bonded to the deck and hull, creating an airtight board.
The board then goes through a two day inflation test, to check for any leaks around the seams and the valve. Once it has passed two days with no drop in pressure, the second 0.9mm rail layer is heat bonded, overlapping the first rail layer. This second layer adds durability to the rails and extra protection against any leaks. Many brands use a single layer on the rail, or add a thin PVC strip over the seam and call that double layer. We call it cheating!
With the second rail layer added, the boards continue their inflation test. The deck pad is fitted with a pre-installed handle and any cargo net attachments, and then bonded to the board under 180PSI of pressure. This ensures the deckpad won’t come un-stuck and start lifting or bubbling, like on many other brands.
All D-Rings, Cargo Nets, RAM Mounts and handles are fitted.
After a minimum total of 1 week of inflation, the finished board pressure is checked one final time before being packaged ready for shipping.
Using the highest quality materials and manufacturing techniques, Freshwater Bay Paddleboard Co iSUPs are 90% rigid at 15PSI. We recommend 15-18PSI depending on the weight of the Rider. Although it certainly isn’t necessary, all our iSUPs are actually rated beyond 30PSI – you won’t find many inflatable paddleboards on the market that can make that claim!