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.
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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.
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Hypalon fabric
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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
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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 9x9 weave
(threads/square centimeter) or a 3x3. The weight of the thread is
important when considering weave density. You can put many pieces of
thread in a square centimeter, but a 2x2 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
