Order the same superyacht fender model in three fabrics and you'll get three quite different products. Hypalon, polyurethane (TPU), and heavy-duty PVC are the three coated textiles that dominate the inflatable yacht-fender market in 2026. They share a similar warranty stack from suppliers like Fendequip (typically 10 years on the fabric, 2 years on welded seams), yet their chemistry, weight, repairability, and price are not interchangeable.
This is where captains get confused. The brochures all show similar-looking fenders. The diameters match. The warranties match. But a CSM Hypalon cylinder cannot be welded, a TPU cylinder can't be glued with PVC adhesive, and an HDPVC drop-stitch panel literally cannot be built from Hypalon. The material is doing different physical work in each case.
What follows is a working captain's guide to the three fabrics. What they actually are, what's true and what's marketing, where each one wins, and what the next-generation alternatives look like. If you want help applying this to a specific yacht and berthing pattern, our superyacht fenders page is the place to start.
What's the best inflatable fender material?
There isn't a single best material. Hypalon (CSM) gives the longest service life (15-20 years) and the strongest chemical resistance, but costs the most and must be glued. Aliphatic polyurethane (TPU) is the lightest, weldable, UV-stable, and increasingly the premium middle tier. HDPVC is the cost-conscious workhorse: 2-3× cheaper at fabric level, easy to repair, with a typical 10-year service life. Match the material to your berthing environment, charter intensity, and replacement budget.
Is Hypalon dead? The DuPont exit explained
The most persistent myth in the inflatable trade is that "Hypalon doesn't exist any more." It's repeated on owner forums, in dealer copy, and occasionally by surveyors. It's not quite right.
DuPont announced on 7 May 2009 that it would close its Beaumont, Texas plant, the only DuPont CSM facility worldwide. Final closure happened on 20 April 2010. The trade name Hypalon died with the plant because DuPont owned the trademark and stopped renewing it. The chemistry, chlorosulphonated polyethylene, did not die.
Production shifted to Tosoh Corporation in Japan, which markets the polymer as Toso-CSM, and to several Chinese producers. The marine-grade coated fabric is then woven and coated by Pennel & Flipo in France (ORCA brand) and Mehler-Heytex in Germany. ORCA is the dominant tier-one supplier for marine inflatables today and ships to most major RIB and tender builders.
The brand died. The chemistry continued. Post-DuPont CSM from a tier-one European weaver is functionally equivalent to the original. Where things get murky is the bottom of the market: cheap Asian CSM mills produce a coating that grades visibly below ORCA 866 on tensile, tear, and UV. So when a fender is described as "Hypalon" today, the only honest follow-up question is which weaver? ORCA, Mehler, or unspecified. The brand on the data sheet has more predictive value than the word "Hypalon."
For deeper context on the brand history, the Wikipedia entry on Hypalon tracks the DuPont exit chronologically.
Hypalon (CSM): the thermoset rubber
CSM stands for chlorosulphonated polyethylene. It's a synthetic rubber, 20-45% chlorine and 1-2% sulphur by weight, with the rest a polyethylene backbone. The chlorine gives it ozone, UV, and chemical resistance. The sulphur is the bridging atom that makes the cure happen.
Curing is what separates CSM from every other fender fabric. Cure happens with metal oxides (magnesium, lead, zinc) which form metal-sulfonate bridges between polymer chains. Once those bridges are in place, the material is locked. CSM is a thermoset, meaning it cannot be re-melted at any temperature short of decomposition. Put a hot air gun on it and the surface degrades long before it softens.
This is why Hypalon fenders, Hypalon RIB tubes, and Hypalon inflatable boats are always glued, never welded. Every seam uses a two-part contact cement (Clifton, Stabond, Bostik 2402) with toluene as the activator. Factory glue lines are precise; field repairs are a specialist job with a 48-hour cure time. Zodiac, Avon, and Bombard still spec Hypalon-coated CSM for their 5.5-metre-plus commercial and military RIBs precisely because the glued construction is field-repairable indefinitely and the cured fabric tolerates fuel spills, oil, and tropical UV better than any thermoplastic.
The trade-off: heavier than TPU (around 1,565 g/m² for ORCA 866 vs 950-1,300 g/m² for TPU), more expensive at fabric level, and incompatible with drop-stitch construction. Where chemical exposure and 15-20 year service life are the priority, Hypalon still wins. Zodiac's own materials guide describes the same trade-off from the RIB side.
Polyurethane (TPU): the weldable middle tier
Thermoplastic polyurethane is the rising star of marine inflatables. Unlike CSM it's a thermoplastic, meaning it can be re-melted, which means it can be welded. Seams go together with a hot-air wedge welder at the factory and with a hot-air gun in the field. No solvents, no glue, no 48-hour cure.
There are two TPU chemistries to distinguish. Aromatic TPU is the cheaper version, used for internal bladder layers and for fenders that won't see direct UV. It has higher puncture resistance but yellows under UV exposure. Aliphatic TPU is the marine-grade outer coating. It does not oxidise under UV, retains pigment colour for the rated service life, and accepts custom colours without bleaching. When a vendor quotes "TPU" for the outer skin of a fender, that should mean aliphatic.
Erez Thermoplastics publishes representative numbers. Their TPU 2051 aliphatic spec is impressive on paper: less than 5 mg loss per 1,000 Taber cycles (abrasion test), 2,000 N puncture resistance, and a service range from -50°C to +70°C. UV stability is rated comparable to Hypalon and abrasion is roughly four times better than CSM by the same vendor's claim. Service-life claims are vendor-published rather than independently audited, but TPU's market growth in the past five years reflects real adoption by mainstream fender brands.
TPU is the premium-but-reasonable middle tier. Lower fabric weight, weldable seams, no UV yellowing, EU phthalate-free compliant, and a price point that sits below Hypalon and above HDPVC. It's where most new fender development is happening in 2026.
HDPVC: heavy-duty PVC for the working fleet
Heavy-duty PVC (HDPVC) is the volume material. It's the cost-conscious specification that powers the SEARAFT inflatable platforms, most Fendequip cylinders, and the majority of charter-fleet fender inventory across the Med.
The marine specification is specific. A proper HDPVC fender fabric starts with a 1,100 dtex polyester scrim (the structural reinforcement), then receives a double or quad PVC coating with UV stabiliser. Fendequip's own HDPVC specification is 1,450 g/m², 1.2 mm thick, four coating layers, with triple-welded seams. That's a long way from a pool-toy PVC.
The European vs Asian quality gap is real, and matters more in PVC than in TPU or CSM. European mills (Mehler-Heytex, Sioen, Pennel & Flipo, Heytex) hit their published g/m² and dtex numbers. Cheaper Chinese mills routinely deliver fabric 30-40% lighter than the spec sheet claims, with weaker UV-stabiliser packages that fade and chalk inside three Mediterranean seasons. Buying HDPVC is buying a mill, not a category.
The economics are simple. Base PVC fabric is roughly 2-3× cheaper than CSM or TPU. PVC seams can be heat-welded rather than glued, which cuts factory labour. The result, in Fendequip's case, is a fender around 15% lighter and 40% cheaper than the equivalent Hypalon unit. That's not marketing inflation; it matches independent fabric-mill arithmetic. The trade-off: shorter service life (10 years typical vs 15-20 for CSM), narrower temperature range (PVC plasticisers stiffen below 0°C and turn tacky above 50°C), and weaker resistance to fuels and aromatic solvents.
Drop-stitch fenders, of the type SEARAFT and Nautibuoy build, almost always use HDPVC. The drop-stitch construction requires thermoplastic seams between the inner threads and the outer skins, which rules out CSM completely. For more on the construction trade-off, see our drop-stitch vs welded seam guide.
Head-to-head spec table
Before reading this table, the key caveat: independent comparative test data does not exist for these three fabrics side by side. Every number below traces to either a mill data sheet (ORCA, Erez, Mehler-Heytex, Fendequip) or vendor marketing. The relative ranking is consistent across sources, but the absolute numbers vary by mill grade. Treat this as a directional comparison, not a procurement specification.
| Property | Hypalon (CSM) | Aliphatic TPU | HDPVC |
|---|---|---|---|
| Fabric weight | ~1,565 g/m² (ORCA 866) | 950-1,300 g/m² | 1,450 g/m² (Fendequip) |
| Tensile (ISO 1421) | 275-700 daN/5cm | Comparable to CSM | Comparable to CSM |
| Tear (ISO 4674) | ~33-35 daN (ORCA 866) | Vendor-published only | Vendor-published only |
| Abrasion (Taber) | Baseline | <5 mg/1,000 cycles (2051) | Roughly equal to CSM |
| UV service life | 15-20 years | ~15 years (vendor) | 10 years |
| Temperature range | -40°C to +150°C | -50°C to +70°C | 0°C to +50°C usable |
| Chemical resistance | Best (acids, fuel, ozone) | Moderate | Poor on fuel and aromatics |
| Seam method | Glued only (thermoset) | Welded or glued | Welded |
| Field repair | Solvent + 2-part cement, 48h cure | Hot-air patch, fast cure | MEK + PVC adhesive, fastest |
| Fabric cost (relative) | 1.0x | ~0.8x | ~0.4x |
Sources: ORCA Engineered Fabrics data sheets; Erez Thermoplastics TPU 2051/2137L specs; Fendequip Hypalon vs PVC vs PU FAQ; Mehler-Heytex HEYboat published specifications. Costs are relative ratios at fabric-mill level, not finished-fender retail.
When each material wins
Match the material to the operating profile, not the brochure.
Hypalon wins when chemical exposure is built into the use case (oil and gas tenders, fuel piers, commercial RIBs working off tankers), when the yacht operates in tropical waters with year-round UV (Caribbean, Indian Ocean, Pacific), or when the budget targets 15-20 years of service from a single set. The price premium amortises across two decades. Zodiac, Avon, and Bombard spec it for commercial 5.5-metre-plus RIBs for exactly this reason.
Aliphatic TPU wins as the all-rounder for premium Mediterranean superyacht use. Wider temperature tolerance than PVC, UV stability approaching Hypalon, lighter than both alternatives (matters when a 60-metre yacht carries 10-14 fenders), weldable for fast field repair, and EU phthalate-free compliant for charter operators sensitive to onboard regulatory exposure. It's the natural choice for a 50-70m yacht doing a Med season plus an Atlantic crossing.
HDPVC wins on cost-per-year for fleets cycling fenders frequently. Charter operators planning a 6-10 year replacement cycle hit the sweet spot here: the fabric cost premium of CSM or TPU doesn't pay back over six seasons. The SEARAFT inflatable-platform business is also entirely PVC because drop-stitch construction needs thermoplastic seams. For the working fleet, HDPVC from a tier-one European mill (Mehler, Heytex, Sioen) is the right answer more often than not.
The next generation
Three trends are reshaping fender fabrics. Aliphatic TPU adoption is the fastest, driven by weldable seams, no UV yellowing, lower weight, and EU phthalate-free compliance. Most new marine-inflatable development at the premium tier is moving here. Bio-attributed PVC (RENOLIT bio@ and equivalent) lets PVC processors swap fossil feedstock for bio-naphtha at the polymer stage with no change to the finished fabric. Rivercyclon, a recyclable polypropylene-based alternative from Rivertex, points at a longer-horizon move away from PVC entirely. Neither has displaced HDPVC or TPU in 2026, but both are visible on the regulatory horizon.
How Mercer Yachting picks
We don't sell a material, we sell a configuration. For a 50-metre charter yacht doing a Med season we'll usually quote a Fendequip HDPVC primary set with a single TPU spare. For a 70-metre explorer with Atlantic-crossing plans and 4 m freeboard we'll often quote aliphatic TPU through and through. For a 90-metre yacht working fuel piers in the Gulf we'll spec ORCA 866 CSM and accept the premium.
We purchase direct from the SEARAFT factory in Nijmegen and from Fendequip in the South West UK, with no exclusive-dealer commitments and transparent pricing. We don't recommend a material because it's what we stock, because we don't stock material. We ship to spec.
If you've read the pillar guide and the size guide and you're ready to map yacht to material, tell us the yacht. We come back within four business hours.
Frequently asked questions
What is Hypalon?
Hypalon is a trade name for chlorosulphonated polyethylene (CSM), a thermoset synthetic rubber with 20-45% chlorine and 1-2% sulphur by weight. It cures with metal oxides into a chemically inert, UV-resistant elastomer that has been used in marine inflatables since the 1960s. CSM cannot be melted once cured, so seams must be glued rather than heat-welded.
Is Hypalon still being made?
The Hypalon brand died when DuPont closed its Beaumont, Texas CSM plant in April 2010. The chemistry continues. Tosoh Corporation in Japan markets it as Toso-CSM, and the marine-grade coated fabric is produced by Pennel & Flipo in France (ORCA brand) and Mehler-Heytex in Germany. Post-DuPont CSM is functionally equivalent to the original when sourced from a tier-one European weaver.
What's the difference between aliphatic and aromatic polyurethane?
Aromatic TPU is cheaper, has higher puncture resistance, and is used for inner bladders. It yellows under UV. Aliphatic TPU is the marine-grade outer coating: it doesn't oxidise under UV, retains colour, and accepts pigments. Erez TPU 2051 (aliphatic) is rated to less than 5 mg loss per 1,000 Taber cycles, 2,000 N puncture, and -50°C to +70°C service. Fenders quoting "polyurethane" for the outer skin should mean aliphatic TPU.
Which material lasts longest?
Hypalon is rated at 15-20 years of service in marine conditions, the longest of the three. Aliphatic TPU sits close behind at around 15 years. HDPVC carries a 10-year typical service life. These figures are mill or vendor-published; no independent comparative test puts the three materials side by side, so treat them as directional rather than precise.
Which material is easiest to repair?
HDPVC is the easiest to repair in the field: MEK solvent plus a PVC adhesive and a patch, no specialist tools. TPU is repaired by heat-bonding a patch with a hot-air gun at coating melt temperature. Hypalon requires toluene and a two-part contact cement (Clifton, Stabond), heat-gun activation at 180-220°C, and a 48-hour cure. CSM repairs are best done by a specialist; PVC repairs you can do yourself.
Why is HDPVC cheaper than Hypalon?
Base PVC fabric is 2-3× cheaper than CSM or TPU at the mill, and PVC seams can be heat-welded rather than glued, which cuts factory labour. Fendequip's published claim that HDPVC is around 15% lighter and 40% cheaper than Hypalon matches independent fabric-mill arithmetic. The trade-off is shorter service life and weaker resistance to fuels and aromatic solvents.
Can a Hypalon fender be welded?
No. Hypalon (CSM) is a thermoset rubber. Once it has cured with metal-sulfonate bridges between polymer chains, it cannot be re-melted. Every Hypalon fender, RIB tube, and inflatable boat seam is glued with a two-part contact cement. This is the fundamental reason drop-stitch inflatable fenders cannot be made from Hypalon: drop-stitch construction needs a thermoplastic outer.
What's the future of fender fabrics?
Aliphatic TPU is the fastest-growing marine inflatable coating: weldable seams, no UV yellowing, lower weight, and EU phthalate-free compliance. Bio-attributed PVC (RENOLIT bio@) and Rivercyclon, a recyclable polypropylene-based alternative, have appeared on the regulatory horizon but have not yet displaced HDPVC or TPU at fender scale in 2026.
Sources: Wikipedia entry on Hypalon (DuPont exit chronology); Fendequip Hypalon vs PVC vs PU FAQ; Erez Thermoplastics aliphatic TPU briefs (2051 and 2137L); ORCA Engineered Fabrics technical sheets (Pennel & Flipo); Zodiac Nautic materials guide; Mehler-Heytex HEYboat published specifications. Mercer Yachting purchases SEARAFT and Fendequip direct from factory and has no exclusive arrangement with any fabric mill.