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A major component of an inflatable is obviously the fabric. Fabric technology has evolved greatly over the last 20 to 30 years, and now includes plastomers, polyurethanes and other fabrics, which can sometimes be stronger, lighter, thinner and less expensive to assemble than the original rubber fabrics. Of course it costs a great deal of money to develop new fabrics or even to switch manufacturing processes to use them. Many manufacturers, big and small, don’t have the will or the resources to do this, and that’s why they generally hide that fact by resorting to condemning new technological advances in fabrics.

For instance, Zodiac’s fabrics have always been on the leading edge of technology and their willingness to research and experiment has led to some innovative new fabrics. These new fabrics are developed to be the best for their intended use. Fabrics used for a small tender don’t need to be the same as those for a large RIB, because the intended use is not the same. Some manufacturers do not have the means or know-how to employ different fabrics, so they just use one. In these cases the consumer, may end up paying too much or getting too little.

Most fabrics consist of a strong, close-weave mesh of polyester or nylon material which is sandwiched between 2 coatings to provide extreme flexibility, superior air and water tightness, as well as resistance to abrasion and the sun’s UV rays. Zodiac uses a polyurethane fabric called “Strongan” and assembles their inflatable boats by thermobonding the fabric.

Hypalon Fabric

HAND-GLUED SEAMS = HYPALON FABRIC Traditional assembly method for hypalon fabric. The 2 panels are glued, one overlapping the other. You will only see part of fabric that covers the other section.   You might see dried glue (browned by the sun) or small areas that are lifting and coming unglued. When scratching Hypalon with your finger nail it often leaves a “scratch mark” also.

Hypalon fabric

THERMOBONDED SEAMS = PVC FABRIC (PVC can also be glued) Robotized hot assembly technique: two layers of fabric are “heat welded” between an exterior reinforcement band and an interior airtight band. What you see is the exterior band, with 2 borders. You might see some small melted fabric bubbles oozing from the edges of the exterior band. You will likely not see small areas that are lifting and coming unglued. When scratching PVC fabric with your nail it likely will not leave a “scratch mark”.  Most PVC boats have some areas that are also glued on – these areas are often around the transom, sometimes the floor and some small parts and handles too.

Strongan fabric  Strongan Fabric

Fabric Differences in Inflatable Boats

The basic difference between boat manufacturer’s fabrics is the chemical composition of the materials used.

In supported fabric boats (those with threads in the material), the fabric strength is measured by the weight of the thread used. Denier or Decitex(metric) is the unit of measure, not a type of fabric.

1000 Denier = 1100 Decitex

The type of thread varies from Dacron to Nylon as does the tightness of the weave. Many heavy duty backpacks are listed at being made of 1000 denier thread. Most foul weather gear is 220 or 440 denier. Zodiac boats are made of 1000 denier and up fabric (the HD’s are as high as 1800). Some other companies vary the weight of the fabric with the weight of the boat. Some “light” duty boats are 200 denier.

The tightness of the weave is another measure. You may have a 9×9 weave (threads/square centimeter) or a 3×3. The weight of the thread is important when considering weave density. You can put many pieces of thread in a square centimeter, but a 2×2 weave of 1/8″ line will
be stronger. Density must make sense with fabric weight.

The coatings and the process of applying the coatings separate the products as well. Zodiac uses a synthetic material which is continually evolving. Using long-chain plastomers (“polymers”), many compounds are formed. Nylon and Polyester are 2 examples. The alternative is to use natural rubber compounds. These are commonly Hypalon and Neoprene in the boating industry.

Synthetic materials allow compounds to be formulated for the specific application. The external coating can be designed for UV and abrasion resistance, while the inner coating can be focused on air integrity. With natural compounds, this becomes more difficult.

Natural fabrics have to be glued to assemble the boat. Zodiac uses a thermo-bonding technique, similar to electronic welding. The welds become stronger than the fabric itself. The welding process also allows a reduction in labor costs and more precise production as it is all automated.

From a reality point of view, both are excellent materials. Each has its weaknesses. The most noticeable difference is that the natural rubber compounds will chalk in the sun. This means you’ might get a red butt when going ashore in your dress whites.

Neither fabric should be treated with a petroleum or silicone based product. An example of such a product would be ArmorAll®. The product won’t hurt the fabric, but it will prevent glue from adhering to the it. You boat will begin to come apart at the seams. There is very little that can be done once this happens. Repairs are difficult at best.

For all inflatables, we highly recommend 303 Protectant, available at automotive stores and the mass merchandisers. It is a water based polymer that inhibits the destructive forces of Ultra Violet rays and it seals the boat against the penetration of dirt. We found that 303 made our boats easier to clean at boat shows and in the display room. 303 can be used on fiberglass, plastic, dash boards, tires, etc. A major benefit is that is does not trap the UV rays inside the coating. This prevents heat build-up, which can be a problem with some other silicone based products. See the link below to order 303.

Heavy Duty Fabrics
Some inflatable boats are still made from a rubber-based fabric called Hypalon. While this is still a very good material, its major downfall is that it can only be joined by gluing, done manually. Problems including poor bonds, delamination of seams or fabric can still affect these glued fabrics. Today, many inflatables are manufactured from polyurethane fabrics, although larger inflatables (particularly RIBs used for rescue or military purposes) use hypalon because thicker hypalon fabrics are still considered to be stronger and more durable than polyurethane. There are some hypalon fabrics that are “2-ply” or a double unit made up of hypalon/weave/hypalon/weave/hypalon and are used for extreme situations including bumper padding, bow skirts, anti-chafe patches and similar applications.

Seams
Apart from its superior toughness and durability, Zodiac’s Strongan fabric allows the use of Zodiac’s computerized machine-welding process known as “thermobonding”, the welding of fabric using hot air. Two sealing strips are thermally bonded to the butted fabric seams in a continuous electrothermal process. A highly airtight seal is created when the narrow inner strip literally melts into the collar material. The wider exterior strip functions as a overlapping structural connection and a sealer against water penetration. Thermobonding creates seams that are typically stronger than the fabric itself and produces a better seam than any hand-gluing method.

Fabric Repair Procedures Located Here