What Is Hypalon® (CSM)? Why It’s the Best Fabric for Inflatable Boats
When it comes to inflatable boats, RIBs (Rigid Inflatable Boats), and professional marine equipment, the fabric used to build or repair the tubes plays a major role in durability, safety, performance, and long-term cost of ownership.
For decades, one material has remained a reference in demanding marine environments: Hypalon®, the name still commonly used in the marine industry for fabrics based on CSM (Chlorosulfonated Polyethylene).
Although the original Hypalon® material is no longer manufactured under that trademark, CSM-based fabrics continue to be widely used for premium inflatable boats, professional RIBs, rescue vessels, military craft, and other applications where resistance to sunlight, saltwater, abrasion, and chemicals matters.
In this guide, we explain what Hypalon® (CSM) is, how it compares with PVC and other inflatable boat materials, why it performs so well in demanding conditions, and how to choose and maintain the right fabric for your boat.
What Is Hypalon®?
From Hypalon® to CSM
Hypalon® was originally a DuPont trademark introduced in the 1950s for a high-performance synthetic rubber known chemically as CSM (chlorosulfonated polyethylene).
DuPont discontinued production of Hypalon® in 2010. However, the name remains deeply established in the marine industry, where it is still commonly used to describe premium CSM-coated fabrics designed for inflatable boats and other demanding applications.
For U.S. boat owners, this distinction is important: when manufacturers, repair specialists, or boaters refer to a "Hypalon boat" today, they are generally referring to a boat constructed from a CSM-based fabric rather than material manufactured under the original Hypalon® trademark.
CSM fabrics continue to be valued because they combine a flexible rubber construction with excellent resistance to the environmental conditions encountered on the water.
Why Is CSM Used for Inflatable Boats?
Inflatable boat tubes are exposed to a particularly demanding combination of conditions. They can spend hours under direct sunlight, come into contact with saltwater, docks, sand, rocks, fuel, cleaning products, and repeatedly flex during inflation, navigation, launching, and storage.
A suitable tube material therefore needs to provide more than simple waterproofing. It must remain flexible, durable, abrasion-resistant, and stable under prolonged exposure to UV radiation and changing temperatures.
This is where CSM-based fabrics have traditionally distinguished themselves from many lower-cost alternatives.
Why Hypalon® (CSM) Is Considered a Premium Boat Fabric
The reputation of Hypalon® comes primarily from its ability to maintain its physical properties in harsh outdoor environments.
CSM offers strong resistance to a range of factors that can gradually degrade inflatable boat fabrics, including:
- UV radiation and prolonged sun exposure
- Saltwater and marine humidity
- Ozone and atmospheric exposure
- High and low temperatures
- Fuel, oils, and many chemicals
- Abrasion and repeated mechanical contact
For boat owners who keep their RIB or inflatable boat in the water or outdoors for extended periods, this resistance can make a significant difference over the life of the vessel.
UV and Sun Resistance
Sun exposure is one of the major long-term challenges for inflatable boats. UV radiation can gradually cause some materials to lose flexibility, fade, crack, or deteriorate.
CSM fabrics are particularly resistant to prolonged UV exposure, which is one reason they are widely associated with premium inflatable boats and professional marine equipment.
This is especially relevant in areas with intense year-round sunlight, including Florida, California, and the Gulf Coast.
Resistance to Saltwater and Marine Conditions
Saltwater, humidity, spray, and repeated wetting and drying cycles can place considerable stress on marine materials.
CSM's resistance to environmental exposure makes it particularly well suited to coastal boating, offshore use, fishing, diving, rescue operations, and professional marine applications.
Resistance to Abrasion
Inflatable boat tubes regularly come into contact with docks, trailers, beaches, rocks, equipment, and other vessels.
A durable outer coating helps protect the fabric from the scuffs and friction that inevitably occur during everyday use. This is particularly important for RIBs and professional boats that are launched and recovered frequently.
Hypalon® vs. PVC for Inflatable Boats
One of the most common questions when choosing an inflatable boat or repairing an existing tube is whether to use Hypalon®/CSM or PVC.
Both materials can be appropriate depending on the boat and its intended use, but they have different characteristics.
Hypalon® / CSM
- Excellent UV resistance for long-term outdoor exposure
- Strong resistance to saltwater and weather
- High abrasion resistance
- Good resistance to fuels, oils, and many chemicals
- Maintains flexibility across a wide range of temperatures
- Well suited to professional and demanding marine use
- Highly repairable over the life of the boat
PVC
PVC remains an extremely common material for inflatable boats, particularly in the recreational market. It is generally lighter and less expensive, making it attractive for occasional use and smaller recreational boats.
However, prolonged exposure to intense sunlight, heat, and harsh marine conditions can make material selection more important. For boaters who prioritize long-term durability and frequent use, CSM is often preferred.
The right choice ultimately depends on the boat's original construction, intended use, storage conditions, and repair requirements.
Which Material Is Better for Repairs?
When repairing an inflatable boat, the most important rule is to match the repair fabric to the original tube material.
A CSM/Hypalon tube should be repaired with a compatible CSM repair fabric and adhesive system, while PVC tubes require materials specifically designed for PVC.
Using the wrong repair material can compromise adhesion and reduce the durability of the repair.
For this reason, identifying the original fabric before starting a repair is an essential first step.
Hypalon® and CSM Marine Applications
Inflatable Boats and RIBs
CSM fabrics are widely associated with premium inflatable boats and RIB tubes, particularly where durability and resistance to harsh conditions are priorities.
Typical applications include:
- Offshore and coastal inflatable boats
- Professional and commercial RIBs
- Law enforcement vessels
- Rescue and emergency boats
- Fishing and diving boats
- Military and government vessels
- High-UV boating environments
The combination of UV resistance, flexibility, abrasion resistance, and chemical resistance makes CSM particularly valuable for boats that need to remain dependable over many years.
Professional and Commercial Marine Use
For commercial operators, rescue organizations, dive teams, and other professional users, the cost of a boat is only one part of ownership.
Downtime, repairs, replacement tubes, and maintenance can all contribute to the total cost of operating a vessel. A durable tube material can therefore provide value beyond its initial purchase price.
This is one reason CSM remains widely associated with professional-grade inflatable boats and RIBs.
Other Marine Applications
CSM-based materials are also used in applications where resistance to weather and chemicals is important, including:
- Dock bumpers and fenders
- Buoys and flotation equipment
- Dive equipment
- Rescue equipment
- Protective marine covers
- Other flexible marine components
Why Hypalon® Performs So Well in Demanding Conditions
Performance in Hot Climates
Inflatable boats operating in warm regions face a combination of high air temperatures, intense solar radiation, hot deck surfaces, and elevated water temperatures.
CSM's resistance to heat and UV exposure makes it particularly suitable for boats operating in southern U.S. states and tropical or subtropical marine environments.
Performance in Cold Weather
Inflatable boats are not limited to warm-water environments. CSM also maintains useful flexibility across relatively cold conditions, making it suitable for boaters operating in northern regions and colder seasons.
As with any inflatable boat fabric, however, owners should follow the manufacturer's recommendations for inflation, storage, and temperature exposure.
Chemical and Fuel Resistance
Marine environments inevitably involve contact with substances such as gasoline, diesel, lubricants, cleaning products, and other chemicals.
CSM provides strong resistance to oils, fuels, and many chemicals, helping protect the fabric from degradation caused by accidental exposure.
This does not mean that chemicals should be left on the tube. Any spill should still be cleaned promptly using an appropriate cleaning method.
Long-Term Flexibility
An inflatable boat tube must flex repeatedly without losing its ability to contain pressure.
Maintaining flexibility over time is therefore just as important as resistance to abrasion or UV exposure. Properly maintained CSM fabrics can remain flexible and serviceable for many years, contributing to the long service life associated with premium inflatable boats.
Repairing Hypalon® and CSM Inflatable Boat Fabric
One of the major advantages of CSM inflatable boat fabric is its repairability.
Small cuts, punctures, worn areas, and damaged sections do not necessarily mean that an entire tube needs to be replaced. When the underlying fabric is still structurally sound, a properly prepared patch can restore the affected area.
When Should You Repair a CSM Tube?
Repair can be appropriate for issues such as:
- Small punctures
- Minor cuts or tears
- Localized abrasion
- Worn patches
- Small areas of damaged coating
- Reinforcement around frequently stressed areas
The condition of the surrounding material is important. A localized repair makes much more sense when the rest of the tube remains strong and flexible.
When Is Replacement More Appropriate?
Not every damaged tube should be repaired indefinitely. Extensive deterioration, widespread cracking, major structural damage, or severe degradation of the surrounding fabric may indicate that replacement is the more appropriate solution.
If you are unsure whether your tube should be repaired or replaced, our guide on repairing vs. replacing RIB tubes can help you evaluate the situation.
Why Matching the Original Fabric Matters
A successful inflatable boat repair depends on more than simply covering a damaged area.
The repair fabric, adhesive, preparation method, and application technique must all be compatible with the original tube material. For CSM/Hypalon tubes, using a compatible CSM repair fabric and adhesive system is essential for achieving a durable bond.
This is particularly important for areas exposed to repeated flexing, abrasion, water pressure, and UV exposure.
Maintenance Tips for Hypalon® Boats
Even the most durable marine fabric benefits from proper maintenance. Good care can help preserve the appearance, flexibility, and performance of CSM tubes over the long term.
Clean the Tubes Regularly
Rinse the boat with fresh water after use, particularly after operating in saltwater. Removing salt deposits, dirt, sand, and other contaminants reduces unnecessary wear on the fabric.
Use Appropriate Cleaning Products
Use a mild soap or a cleaner specifically designed for inflatable boat fabrics. Avoid aggressive solvents, abrasive products, or chemicals that are not intended for the material.
Protect the Boat From Prolonged Sun Exposure
CSM is highly resistant to UV radiation, but minimizing unnecessary exposure can still help extend the life of the boat.
When possible, store the vessel under cover or use an appropriate boat cover during extended periods when it is not being used.
Inspect the Tubes Regularly
Look for cuts, abrasion, worn areas, loose seams, or other signs of damage before and after periods of intensive use.
Identifying a small problem early can prevent it from developing into a much larger repair.
Hypalon® vs. PVC: Which One Should You Choose?
There is no single material that is ideal for every inflatable boat.
PVC can be an excellent choice for lightweight recreational boats and owners looking for an affordable solution. It offers advantages in weight, price, and manufacturing efficiency.
CSM/Hypalon, on the other hand, is particularly attractive for boaters who prioritize:
- Long service life
- Frequent use
- UV and weather resistance
- Saltwater exposure
- Abrasion resistance
- Repairability
- Professional-grade performance
For demanding applications, CSM remains one of the benchmark materials for inflatable boat and RIB construction and repair.
The best material is therefore the one that matches the boat's original construction and the conditions in which it will be used.
Why Orca Retail Uses Hypalon Repair Fabrics
For inflatable boat owners and marine professionals, choosing a repair fabric is about more than finding a material that covers a damaged area. The repair needs to remain reliable after exposure to sunlight, saltwater, abrasion, temperature changes, and repeated flexing.
Orca Retail offers CSM/Hypalon repair fabrics designed for professional and long-lasting inflatable boat repairs.
Our repair materials are designed to:
- Match original inflatable boat fabrics
- Provide reliable compatibility with appropriate adhesives
- Withstand UV exposure, saltwater, and abrasion
- Support durable professional-grade repairs
Whether you are repairing a recreational RIB, a professional inflatable boat, or marine equipment exposed to demanding conditions, using the appropriate repair fabric is essential for achieving a dependable result.
For boat owners who depend on their vessel rather than simply using it occasionally, quality repair materials can make a significant difference to long-term reliability and peace of mind on the water.