Offshore protection in hydraulic engineering describes the design and installation of geotextile systems that defend coastal structures, breakwaters and offshore foundations against scour, wave action and seabed erosion. Unprotected seabeds and coastal structures are vulnerable to progressive erosion caused by tidal currents and hydrodynamic wave forces. Secutex® H geotextile filter mats and Secutex® Soft Rock geotextile sand containers provide proven, durable protection – independently approved by the Federal Institute for Waterways Engineering (German Bundesanstalt für Wasserbau, BAW).
Naue prodcut solutions are deployed wherever coastal and offshore structures require reliable, long-term protection against hydrodynamic forces.
Geotextile sand containers protect monopile foundations from scour erosion in open-sea conditions using Secutex® Soft Rock.
Filter mats stabilise the seabed base layer beneath rock armour on breakwater structures using Secutex® H or Secutex® HB.
BAW-approved filter systems ensure long-term stability of coastal erosion control structures in exposed environments.
Offshore and coastal installations impose extreme demands on geotextile products. Secutex® H filter mats and Secutex® Soft Rock containers are engineered to withstand the full range of marine installation stresses: wave action, heavy stone armouring and underwater placement.
Practical advantages:
In hydraulic engineering, preventing fines from migrating through or beneath a protective structure is as important as the mechanical load-bearing function. Fine sand particles in coastal and offshore substrates can be mobilised by wave pressure and tidal currents, causing progressive undermining of armour layers.
Key principle: Filter stability prevents progressive erosion beneath the armour layer. Separation maintains long-term structural integrity.
Technical core benefit: Continuous filter layer across the full structure footprint prevents fines washout.
Product selection depends on the type of offshore protection required, the seabed substrate, the hydraulic load and the installation method available. Use this decision guide to identify the optimum system for your project.
| Criterion | Secutex® H | Secutex® HB 751 | Secutex® Soft Rock R 801 |
|---|---|---|---|
| Application type | Flat base filter beneath armour stone | Flat filter with negative buoyancy for underwater installation | 3D scour infill around offshore foundations |
| Seabed substrate | Sandy / fine-grained; soil types B + C; placed on a wet beach | Sandy substrate; rapid sinking essential | Sandy / granular fill in containers; deployed by crane/barge |
| Wave / hydraulic load | Moderate wave action; covered by armour stone | High-energy sites; immediate sinking critical | High currents (up to 0.8 m/s); design wave Hmo = 8.4 m |
| Installation method | Excavator + spreader bar; roll-out on the seabed; no divers | Roll-out underwater without divers; 4.8 m wide rolls | Barge or crane; pre-filled on land; independent of piling |
| BAW approval | Yes: RPG soil types B + C; 1,800 Nm perforation | Yes: RPG 1,800 Nm; negative buoyancy confirmed | Yes: R 801 product range; APAC-certified types available |
| Recommended product | Secutex® H | Secutex® HB | Secutex® Soft Rock R 801 |
Approx. 67% less material than mineral scour protection
At Amrumbank West offshore wind farm, the geotextile scour protection system required only 362 m³ of material compared with 1,086 m³ for a conventional mineral approach – approximately two-thirds less. This directly reduces rock quarrying, transport volumes and offshore vessel charter time.
No specialist divers required for underwater installation
Secutex® HB sand mats sink immediately on contact with water due to the integral ballast layer. Rolls are deployed by excavator with a spreader bar. Complex underwater profiling by specialist divers is not required.
Direct armouring with heavy rock
BAW RPG testing at 1,800 Nm confirms that armour stone can be placed directly onto Secutex® H. This eliminates the need for a separate graded granular filter layer, reducing construction steps, material quantities and overall project cost.
BAW-approved and compliant with international standards
All Naue offshore geotextile products are independently approved by the BAW. This provides specification engineers and procurement teams with the regulatory certainty required for public and private hydraulic infrastructure projects.
Offshore protection in hydraulic engineering refers to the installation of geotextile filter mats and sand containers to defend coastal structures, breakwaters and offshore foundations against scour erosion, wave action and seabed destabilisation. Naue's Secutex® H and Secutex® Soft Rock systems are deployed on projects from offshore wind farms to harbour extensions and coastal defence schemes.
Secutex® H and Secutex® HB are flat filter mats suited to providing a continuous base layer under armour stone – for breakwaters, groynes and revetments. Secutex® Soft Rock sand containers are best suited where three-dimensional infill is required around offshore foundations such as monopiles. Both products can be combined for complex foundation protection.
Naue offshore products are tested to EN ISO 9864 (mass per unit area), EN ISO 10319 (tensile strength), EN ISO 12956 (characteristic opening size) and EN ISO 11058 (water permeability). All products in the Secutex® H and Secutex® Soft Rock ranges hold BAW RPG approval, covering perforation resistance at 1,800 Nm, filtration efficiency and abrasion resistance for hydraulic engineering applications.
At the Amrumbank West offshore wind farm, the geotextile scour protection system required approximately 362 m³ of material compared with 1,086 m³ for a mineral alternative – a saving of approximately 67%. Reduced material volume directly lowers offshore logistics costs, vessel charter time and transport costs. Contact Naue for a project-specific comparison.
Secutex® HB is supplied on 4.8 m wide rolls. The integral sand ballast layer (mass per unit area up to 8 kg/m²) causes the geotextile to sink immediately on contact with water. Rolls are deployed by an excavator fitted with a spreader bar and can be unrolled directly into anchor trenches. No specialist divers are required even in confined underwater conditions.
BAW RPG approval is issued by the Bundesanstalt für Wasserbau (Federal Institute for Waterways Engineering, Germany) for geotextile products in hydraulic engineering. RPG testing covers resistance to dynamic perforation loads at 1,800 Nm, hydraulic filtration efficiency against specified soil types and abrasion resistance. BAW approval provides independent third-party validation of hydraulic performance, giving specifiers and clients confidence in long-term product behaviour.
Yes. The integral sand ballast layer ensures that Secutex® HB achieves negative buoyancy immediately on contact with water, allowing controlled deployment even in tidal or flowing water conditions. The 4.8 m wide rolls and sewn seam construction prevent panel displacement during and after installation under current loading. Maximum allowable current velocity during installation should be confirmed with Naue technical support based on site-specific conditions.
Secutex® Soft Rock containers are filled with locally available sand or fine granular material using a purpose-designed filling nozzle on the land before offshore deployment. Each container holds approximately 1 m³ of fill, giving a filled weight of approximately 1,400 kg. Using local sand eliminates the need to quarry and transport heavy aggregate to the offshore site, significantly reducing material costs, vessel movements and transport costs.
The design of geosynthetic systems for offshore protection is carried out on the basis of recognised hydraulic engineering standards. Naue's technical team supports engineers in identifying the optimum system for site-specific hydraulic boundary conditions.
Naue Secutex® H is a geotextile for separation and filtration in hydraulic engineering, coastal protection and waterway construction.
Naue Secutex® Soft Rock is a geotextile sand container for coastal protection, scour protection and riverbank stabilisation.
