01Fabric Families: PVC vs CSM (Hypalon®)
PVC is the cost-efficient standard: it welds easily by high frequency, takes colors well and suits most recreational and rental duty. Quality is graded by weight — 1100 g/m² is a common working grade for boat collars.
CSM, known by the trade name Hypalon®, is the premium choice: superior resistance to UV, fuel, chemicals and abrasion, with better flex life in extreme climates. It cannot be RF welded, so it is thermally welded or adhesive-bonded — one reason boats built with it cost more.
02Chamber Design and Baffles
Tubes are divided into separate air chambers by internal baffles. More chambers mean more safety margin — a punctured chamber leaves the rest of the tube supporting the boat — and most boat collars carry three to five chambers plus a keel chamber where applicable.
Ask any supplier how many independent chambers their configuration has and what happens if one fails. A credible answer comes with drawings, not adjectives.
03Seams: RF and Thermo Welding
Overlap seams join fabric panels; the weld quality decides whether the seam outlives the fabric. RF welding melts the coating between electrodes under controlled temperature, pressure and dwell time — parameters logged per production run on mature lines.
CSM fabric relies on thermal welding or hand-applied adhesive systems done by experienced operators. Whichever method applies, ask how seam integrity is inspected and what reject rate the process tolerates.
04Valves and Pressure Testing
Industry-standard push-and-turn inflation valves let crews inflate and deflate quickly and replace valves without special tools. Valve seats should be inspectable and spares orderable — valves are the one consumable part of a tube.
Finished chambers are proof-tested: we hold every chamber at 0.35 bar for 24 hours and auto-reject anything dropping more than 0.02 bar. When you compare factories, ask for their exact test pressure, hold time and rejection threshold — vague answers here predict vague quality.