UNDERWATER & HYPERBARIC OPERATIONS

Contact us today to discuss your specific needs and discover how our expertise can ensure the success of your project — whether offshore or onshore.

SIDON — Your trusted partner for professional underwater solutions.

SIDON — A Reliable Partner in France and Beyond

SIDON Construction specializes in underwater and hyperbaric works, both in France and abroad (Belgium, Switzerland, French overseas territories, etc.). Thanks to a full team of certified commercial divers — Category A and Category B — we operate with precision and responsiveness in complex environments across all types of submerged zones: sea, rivers, canals, ports, basins, locks, wastewater treatment plants, industrial sites, and power stations.

Our divers are trained to the highest standards, ensuring efficient, safe interventions that fully comply with hyperbaric regulations (French decree of September 29, 2017).

Whether your project is offshore or onshore, we are ready to take on any technical challenge. Safety, operational performance, and environmental protection are at the core of everything we do.

At SIDON Construction, we don’t just dive — we assess, act, and secure. Thanks to our multi-site experience and deep understanding of submerged environments — port, industrial, river, or maritime — we deliver concrete, actionable solutions at every stage of your project.

Our interventions are based on precision engineering, tailored equipment, and certified teams capable of adapting to every configuration — even the most complex.

SIDON carries out the cutting and trimming of submerged piles or sheet piles, regardless of the site configuration. Our certified commercial divers use thermal techniques such as oxy-cutting and arc-air gouging, as well as adapted mechanical methods. Each intervention is performed with precision, in full compliance with current hyperbaric safety standards.

Underwater Cutting and Recapping of Steel Piles and Sheet Piles

Installation and sealing of underwater concrete structures

SIDON carries out the installation of fenders, slabs, supports, and other concrete structures in complex submerged environments. Our commercial divers are skilled in underwater formwork, concrete injection, and mechanical or chemical anchoring. Each intervention is tailored to the site’s specific constraints to ensure strength, durability, and safety.

Underwater Reinforcement of Quays and Floating Pontoons

SIDON carries out reinforcement of quay, pontoon, and port structures exposed to hydraulic forces. Our teams perform shoring, concrete repairs, and installation of reinforcements underwater, in a controlled environment. Each operation aims to restore stability and extend the lifespan of existing infrastructures.

Underwater Anchorage and Base Plate Fixing

SIDON carries out the sealing of base plates, anchorages, and metal fixings in submerged environments using suitable materials. We use special resins and hydraulic mortars designed to ensure optimal adhesion underwater. Our interventions guarantee the strength and durability of assemblies, even under extreme conditions.

Installation of Mooring Deadweights and Mooring Lines

SIDON installs mooring systems tailored to each port or river configuration. Our teams ensure anchoring using concrete blocks, helical screws, driven piles, or dredging, depending on the soil conditions. Each installation is designed to ensure the safety, stability, and longevity of the mooring system.

Fixed and Floating Pontoon Installation

SIDON installs pontoons tailored to maritime, river, or port environments, whether fixed or floating. Our commercial divers ensure precise alignment, fixation, mechanical assembly, and underwater anchoring. Each structure is installed in compliance with safety and durability standards.

Maintenance and Raising of Deadweights (Salvage Operations)

SIDON carries out maintenance and refurbishment of existing mooring blocks and mooring systems. Our teams conduct inspections, cleaning, and replacement of worn chains, cables, or connectors. These operations ensure the long-term reliability and safety of the installations.

Emergency Interventions for Submerged Structures Repairs

SIDON responds swiftly to failures in submerged structures requiring immediate action. Our commercial divers carry out sealing, installation of patches, or waterproofing covers to temporarily secure the structure. These emergency interventions minimize risks and ensure operational continuity until permanent repairs can be made.

Underwater Shielded Metal Arc Welding (MMA)

SIDON carries out shielded metal arc welding (MMA) underwater for the assembly or repair of metal structures. Our certified commercial divers are skilled in handling the specific challenges of underwater welding, even in difficult conditions. This expertise ensures strong, durable welds that comply with safety standards.

Underwater Mechanical Operations (Valves, Turbines, Gates, and More)

SIDON handles the maintenance and repair of submerged mechanical equipment such as valves, turbines, flaps, and pumps. Our commercial divers work directly underwater to carry out disassembly, replacement, lubrication, or adjustments, without the need to remove the equipment from the water. This approach minimizes downtime and ensures optimal functioning of technical installations.

Manual and Mechanical Dredging Operations (Pumping, Suction, Air-Lift Techniques)

SIDON carries out dredging of basins, ports, locks, and wastewater treatment plants (WWTPs) using techniques tailored to each site. Our teams employ pumping, suction, or air-lift methods to efficiently extract accumulated sediments. This intervention helps restore the hydraulic capacity of structures and optimize their operation.

High-Pressure Cleaning and Mechanical Brushing Operations

SIDON ensures the cleaning of submerged structures by removing encrustations, algae, and marine deposits. Our divers use high-pressure equipment or mechanical brushes specifically designed for the underwater environment. These operations guarantee the durability of structures and the proper functioning of submerged installations.

Underwater Environmental Remediation

SIDON carries out environmental remediation in aquatic areas impacted by pollution, in river, port, or industrial environments. Our teams implement suitable methods such as manual collection, selective dredging, or pollution containment. Each intervention is performed in strict compliance with environmental and safety regulations.

Submerged Pipeline Installation (HDPE, Steel, Concrete)

SIDON carries out the installation of submerged pipelines for supply, discharge, or drainage networks. Our commercial divers ensure the guidance, weighting, and assembly of pipes using couplings, flanges, or welding. Each operation is tailored to the site’s specific constraints to ensure the sealing, stability, and long-term durability of the installations.

Pipeline Burial or Stabilization (Including Landfall Installations)

SIDON performs the burial and stabilization of submerged pipelines, including sensitive landfall areas. Our teams apply various techniques based on the configuration, such as sand bedding, sandblasting, gravel placement, rock armor, or the installation of concrete mattresses. These solutions ensure the long-term protection of pipelines against currents, soil movement, and external impacts.

Underneath Structure Passage or Crossings (Directional Drilling, Core Sampling)

SIDON carries out technical crossings beneath structures such as bridges, roads, or dikes, combining both land-based and underwater methods. Our teams use directional drilling, coring, and other hybrid techniques to navigate obstacles without disturbing existing structures. These interventions enable the installation of networks or pipelines in constrained and sensitive environments.

Underwater Visual Inspections (UVI, Civil Engineering Structures and Artworks)

SIDON carries out underwater visual inspections (UVI) to assess the condition of submerged structures according to IQOA standards, particularly for CEREMA or public sector clients. Our commercial divers use direct observation, helmet-mounted cameras, handheld cameras, or ROVs for precise monitoring. These inspections help identify defects, establish reliable diagnostics, and guide maintenance actions.

Underwater Non-Destructive Testing (NDT)

SIDON performs underwater non-destructive testing (NDT) to assess the condition of metal and concrete structures. Our certified commercial divers use methods such as ultrasonic testing, magnetic particle inspection, dye penetrant testing, as well as corrosion surveys and measurements of paint or coating thickness. These precise inspections help anticipate degradation and reliably plan repairs.

Underwater Bathymetric & Topographic Surveys

SIDON performs precise surveys of seabeds and submerged structures using multibeam echo sounders, differential GPS, bathymetric lasers, or manual methods. These survey campaigns allow for accurate mapping of profiles, anomaly detection, and monitoring of underwater area changes. Our services are tailored to the needs of ports, dams, canals, and both industrial and inland waterway zones.

Underwater Imaging and Technical Reporting

SIDON offers real-time video inspections to accurately observe and document the condition of submerged structures. Our equipment enables high-definition recording with options for georeferencing and technical annotation. A detailed report is provided for each mission to ensure traceability, clarity, and fast decision-making.

Wreck, Float, and Heavy Object Recovery Operations

SIDON carries out the recovery of submerged objects using solutions tailored to each configuration: lifting bags, pumping systems, flotation structures, inflatable parachutes, or pontoons. Our teams ensure the safe lifting and stabilization of objects, in full compliance with technical and environmental constraints. Each operation is carefully planned to minimize risks and ensure the success of the salvage.

Support for the Installation of Underwater Components

SIDON supports the installation of heavy or technical elements underwater by providing real-time guidance, alignment, and visual control. Our commercial divers work in close coordination with surface teams to ensure precise and secure positioning. This assistance is essential to the success of complex submerged installations such as piles, slabs, or port equipment.

Subsea Lifting and Winching Operations

SIDON performs underwater lifting and winching operations using hydraulic systems, manual hoists, or sealed motorized lifting equipment. Our commercial divers ensure the safe installation, movement, or repositioning of heavy loads underwater. These operations are often part of assembly, maintenance, or salvage projects.

Servicing of Submerged Structures such as Canals, Bar Screens, and Basins

SIDON provides regular maintenance of submerged structures such as canals, basins, and bar screen systems. Our teams carry out cleaning, routine repairs, and diagnostics to ensure continuous operation and prevent failures. These interventions are essential to preserve hydraulic efficiency and extend the lifespan of installations.

Emptying and Desilting of Basins and Confined Structures

SIDON carries out operations in enclosed or confined structures, including draining, desilting, and technical cleaning. Our teams are trained to operate in specific environments such as contaminated air, explosive atmospheres (ATEX), or confined spaces. Each intervention is conducted in strict compliance with safety protocols and personal protective measures.

Operations in Water Treatment Units (Digesters, Clarifiers, and More)

SIDON operates within water and sludge treatment units, such as digesters, clarifiers, and biological basins. These sensitive environments require advanced technical expertise and thorough control of biological, chemical, and atmospheric risks. Our teams work safely, following strict procedures tailored to the specific constraints of each site.

Cathodic Protection (Sacrificial Anodes or Impressed Current Systems)

SIDON implements cathodic protection systems to prevent corrosion of submerged metal structures. We install sacrificial anodes or impressed current systems, ensuring secure connections in full compliance with applicable standards. This protection extends the service life of structures and significantly reduces long-term maintenance costs.

Underwater Resin or Concrete Injection

SIDON intervenes to fill cavities, scour zones, or underpin structures using technical resin or underwater concrete injection. These operations help stabilize foundations, restore watertightness, and reinforce weakened structures. Each solution is tailored to the site constraints and the specific characteristics of surrounding materials.

Structure Foundations: Micropiles, Grouting, and Reinforced Concrete Bases

SIDON carries out submerged foundations for all types of structures using micropiles, grouting, or concrete blocks. Our teams apply drilling, injection, or piling techniques depending on the soil conditions and project constraints. These foundations ensure the stability, strength, and long-term durability of structures installed in aquatic environments.