Description of the Nitrider gas spring 100089 – 400 N – Stroke 300 mm
The 100089 Nitrider® gas spring is a compression gas strut manufactured by Associated Spring SPEC UK / Barnes Group UK Ltd (Evesham, UK), originally produced to the specification of Dufour Yachts — one of the most respected names in French performance sailing yacht construction. This is a direct OEM replacement for the original factory-fitted unit on Dufour vessels where this reference was specified at build, and an appropriate choice for refit professionals seeking a reliable, proven strut in the same force class.
The strut belongs to the Nitrider® N10 series: a 10 mm rod diameter and 23 mm tube diameter, threaded M8 x 1.25 at each end. The Nitrider® process applies a thermochemical surface nitriding treatment to the carbon steel rod, creating a hard, wear-resistant black outer layer that substantially extends rod seal life and corrosion resistance compared to a standard untreated carbon steel strut. The tube body receives a black e-coat finish per the GSNI specification, giving the complete assembly a uniform, professional black appearance suited to any interior or semi-exposed nautical environment.
With a force of 400 N and a stroke of 300 mm, this unit covers a broad range of medium-to-large hatch and panel applications aboard Dufour yachts and similar production sailing boats: cockpit locker lids, chart table panels, engine compartment access covers, or any mechanism where a generous stroke combined with a firm holding force is required. The body length (L1) is 649 mm, and with both zinc-plated EF-BS009Z ball sockets fitted the centre-to-centre length (L2) reaches 685 mm.
The end fittings are EF-BS009Z zinc-plated steel ball sockets: cage-type metal sockets with a compact 18.5 mm body length, Ø10 mm ball seat, and M8 x 1.25 threaded shank. The zinc plating provides practical corrosion protection suitable for protected interior and semi-exposed locker environments. The revision history of this drawing (Rev D) records that the end fitting specification was updated from EF-BS006Z to EF-BS009Z — a change to a more compact socket profile while retaining the same Ø10 ball and M8 x 1.25 thread. The sealed cylinder body carries the standard Ressorts SPEC pressure warning label confirming the unit must never be drilled, cut, or exposed to heat.
Distributed in France through Ressorts SPEC, the authorised partner for Associated Spring / Barnes Group components.
Specifications
- Reference: 100089 – Rev D
- Type: Nitrider® compression gas spring
- Force (P1): 400 N
- Stroke: 300 mm
- Body length (L1): 649 mm
- Centre length with end fittings (L2): 685 mm
- Rod diameter (ØR): 10 mm
- Tube diameter (ØT): 23 mm
- Thread: M8 x 1.25
- End fittings (both ends): EF-BS009Z – zinc-plated steel ball socket, Ø10 mm ball, M8 x 1.25, 18.5 mm body length
- Rod finish: Nitrided black (GSNI specification)
- Body finish: Black e-coat (GSNI specification)
- Original customer: Dufour Yachts
- Manufacturer: Associated Spring SPEC UK / Barnes Group UK Ltd, Evesham
Installation / Maintenance
Installation:
- Clip the EF-BS009Z zinc-plated ball sockets onto the 10 mm ball studs at each mounting point. Align the strut axis with the direction of hatch or panel travel to prevent lateral side-loading on the rod seal and end fittings.
- Before fitting, verify the 685 mm centre-to-centre length (with end fittings) matches the mounting geometry on the vessel — always measure the old strut tip-to-tip before removing it.
- Where the installation geometry permits, orient the strut with the rod end facing downward to preserve the lubrication film on the rod seal and maximise service life.
- At 400 N, ensure that the ball studs and their supporting structures are adequately dimensioned and fastened to withstand the applied load without deflection over time.
Maintenance:
- Inspect the zinc-plated ball sockets periodically for wear, play, or surface corrosion — particularly after prolonged offshore passages or winter lay-up in salt-laden air.
- Apply a light coat of marine-grade silicone lubricant or corrosion-inhibiting grease to the ball joints at each annual service to maintain smooth articulation and extend socket life.
- Wipe down the Nitrider® rod occasionally with a cloth lightly moistened with silicone oil to keep the rod clean and maintain the seal lubrication film.
- The gas strut body is a sealed, pressurised unit — never drill, pierce, cut, or heat it. Replace as a complete assembly when the holding force has noticeably diminished or the rod seal weeps oil.
Our review
✔️ Pros :
- Nitrider® rod treatment significantly extends wear resistance and service life compared to standard untreated carbon steel gas struts of the same size class.
- 400 N force and 300 mm stroke cover a wide range of medium-to-large hatch and panel applications aboard Dufour yachts and comparable production sailing vessels.
- EF-BS009Z zinc-plated steel ball sockets offer a robust metal joint with a compact 18.5 mm profile — lower profile than the EF-BS006Z while maintaining the same Ø10 ball and M8 thread standard.
- OEM-grade component from Associated Spring / Barnes Group, the original equipment supplier to Dufour Yachts — guaranteed dimensional and force accuracy for direct replacement.
- Uniform black finish (nitrided rod + e-coat body) integrates cleanly into any locker or panel cavity.
❌ Cons :
- Nitrider® carbon steel construction is more corrosion-resistant than plain carbon steel, but not equivalent to 316L stainless; best suited to protected interior or semi-sheltered locker environments rather than fully exposed, permanently wet deck applications.
- Zinc-plated ball sockets may show surface corrosion in permanently damp or high-salinity environments over extended periods; consider stainless steel socket alternatives for more aggressive conditions.
- Fixed force of 400 N — verify this matches the load and geometry of your specific hatch or panel before ordering.
- The 685 mm centre-to-centre dimension is fixed; always measure the existing strut tip-to-tip before purchasing to ensure a correct fit.
Conclusion
The 100089 is the correct direct replacement for Dufour Yachts vessels originally fitted with this OEM reference, and a sound choice for any refit project requiring a reliable medium-force Nitrider® gas strut in this size class. Its 400 N force, 300 mm stroke, and compact zinc-plated ball sockets make it well-suited to cockpit locker lids, chart table panels, and engine bay access covers in sheltered or semi-exposed nautical environments. Before ordering, confirm that your mounting geometry corresponds to the 685 mm centre-to-centre dimension with fittings in place, and that 400 N is the correct force for your application. For installations subject to prolonged direct saltwater exposure, consider upgrading to a 316L stainless steel gas spring with stainless ball sockets for added durability.
Good to Know
- OEM reference produced for Dufour Yachts — verify fitment by measuring the existing strut on your vessel before ordering.
- End fittings: EF-BS009Z – zinc-plated steel ball socket, Ø10 mm ball, M8 x 1.25, 18.5 mm body length (both ends). Revised from EF-BS006Z at Rev D — same ball diameter and thread, more compact socket body.
- Total centre-to-centre length with fittings: 685 mm. Body length alone (L1): 649 mm. Always measure the old strut tip-to-tip before purchasing.
- Nitrider® series: rod is nitrided black and body is e-coated black per GSNI specification — enhanced rod wear resistance compared to plain carbon steel, suited to interior and semi-exposed protected environments.
- The cylinder body is a sealed, pressurised unit — never drill, pierce, cut, or heat it.
- Distributed in France by Ressorts SPEC — original manufacturer: Associated Spring SPEC UK / Barnes Group UK Ltd.
- Browse our full range of marine gas springs for other force ratings, stroke lengths, and material options including 316L stainless steel.
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