Category Archives: Services

Marine Civils


CDC is always committed to maintaining high health and safety standards on any site & can undertake any civils project with commitment & problem solving by providing simple but practical solutions. CDC has gained vast civils experience over the years and prides itself in completing a project efficiently while doing as little harm to the environment as possible.

CDC diving services can support civil construction/ demolition work with regards to:
• In-water Port construction, repairs & maintenance
• Salvage
• Slope revetment.
• Dredging & airlifting
• Underwater welding and cutting (Hydraulic/Broco)
• Complete slipway builds.
• Slipway maintenance
• Life extension of assets by means of cathodic protection.
• Pipeline installations and maintenance as well as valve removal and replacement.
• Sheet piling repairs and quay wall repairs.
• Quayside rehabilitation.
• Core drilling and grouting.
• Underwater concrete casting and shutter board assembly.
• Hydraulic fender installations.
• Quay wall inspections and repairs.
• Underwater structural inspections.
• inland construction, repair & maintenance for dams, reservoirs & bridges water systems
• Leak detection
• Demolitions



CDC has successfully completed five salvage operations. One being the removal of 80 tons of diesel from the fishing vessel, Baratz, that sank off Cape Recife in 30 meters of water. Another salvage was the Larianna, a 60 tonne concrete vessel that sank in Port Elizabeth harbour & the reflaoting of the Knysna Paddle Cruiser. CDC has a 24hr rapid response maritime emergency team.

CDC Diving can support salvage work with regards to:
• Floating sunken vessels.
• Wreck removal of shipwrecks.
• Rigging and lifting.
• Cutting up & wreckage removal.
• Environmental clean-up of wreck sites as well as fuel, oil and hazardous substance removal.
• 24hr rapid response team



CDC is committed to offering efficient dredging services at reasonable rates. CDC specializes in dredging hard to access places where larger dredges cannot reach. CDC has a wide range of dredging equipment and can accommodate any dredging requirements received from clients.

CDC Diving Services can support Dredging Operation with regards to:
• Deepening of harbours.
• De-silting.
• Sand bypass systems.
• General overburden removal.
• Dredging in hard to access places.
• Sump clean outs.
• Dredging of slipways.
• Sinking caissons into mud/sand.
• De-silting of sunken vessels.
• Deepening of dams
• Silt, mud & grit removal of reservoirs

Completed Projects


Titanium Explorer
• Biofouling removal & reclamation of Drill ships 45 Sea chest gratings, 6 thrusters, OBV’s & inspection of moon pool anodes & welds.

Knysna Paddle Cruiser
• South Africa’s only paddle cruiser took on water on port side submersing half the vessel. The CDC team spent gruelling long hours to re-lift the paddle cruiser using 25tons of lift bags & pumps. Knysna.

Burgersdorp reservoir
• Inspection, leak detection of reservoir walls & dredging of silt from floor.

Tanker berth
• Installation of support I-beams on emergency escape walkway columns using hydraulic drill, hydraulic grinder broco cutting & torqueing tools. Completed from our dive support barge. Port of Port Elizabeth.

Blackwoods farm reservoir
• Inspection & Plugging of reservoir outlet pipes for valve maintenance.

• 12 Great white shark monitoring station retrieval & installation along Algoa bay.

Lovemore Heights reservoir
• Inspection & Plugging of reservoir outlet pipes for valve replacement.

National Salt
• Removal of sea water intake flange grating in shore break for Cerebos salt.

• Various salvage & rubble removal in Port of Port Elizabeth & Port of Ngqura.

Ensco 5000 Rig
• Connect tow lines for tug.
• Standby dive support on ballasting / de-ballasting.
• CCTV Pontoon inspection on the harbour floor.
• Detaching tug tow lines and bridal.

Fender Recovery
• Search and retrieve fallen 8-ton fender from the bottom of the Couga harbour 21 meters deep.
• Rig up fenders to the crane for removal.
• Located and removed 25 fenders.
(Equipment used SSDE systems and 25ton crane.)
Hydraulic Fender Installation
• Rig up fender brackets to the crane.
• Position and fasten fender brackets to frame.
• Inspect hydraulic fender pads.

Haw & Inglis 40 Ton Lead in Jetty Construction
• Remove debris in path of piling machine.
• Cut away and remove old Jetty in the path of piling machine.
• Dredging to be able to cut old jetty off low enough to design level.

Couga Dam Job
• Removing blanks in dam wall caisson at 45m, 30m, 18m and at 9 m.
• Removing snorkel pipe from 45m with Tirfor.
• Inserting bird cage strainer – outlet at 45m.

Sheet Piling
• Repairing holes in sheet piling with sheet plate.
• Identifying void cavities in quay-walls.
• Breaking open of quay wall to expose cavities.
• Filling of cavities with rock and concrete to restore structural stability to the quay wall.

• GPS positioning of 12 caissons with barge.
• Dredging all 12 caisson down to design level. For example:
1. Installation of reinforcing inside the caisson.
2. Placing concrete beams across 12 caisson.
3. Filling of 12 caisson with concrete using boom pump.

Boratz Salvage /Wreck Decontamination
• Locating the wreckage using side scan sonar.
• Removal of all rope from the wreckage, which could pose as a shipping hazard.
• Removal of line hauler winch. Cut free with a hydraulic grinder.
• Removal of all oil drums and hazardous substances.
• Drilling of holes into fuel tanks to remove 80 tons of diesel.
• Complete decontamination of the wreck was successful.

Basil Read
• Placing of Grade 1t2 rock for anti-scouring purposes.
• CCTV surveys of breakwater, inspection of voids, 3 point.

Larianna Wreck Removal
• Locate the position of wreckage using SSS.
• Dredge mud out of wreckage holds with G” dredge.
• Jet lifting straps under belly of the wreckage.
• Using lifting bags and barge lifted vessel, tow to quay wall. Cut up vessel H/G.

Syncro #2 Salvage
• Rig up lifting bags and barge crane to vessel.
• Lift vessel to the surface.
• Seal sea cocks of vessel.
• Floated vessel by S pumping water out using 3 x 4″ trash pumps and one electric 6″ submersible.

Harbour Wall Surveys
• CCTV surveys of Port Elizabeth’s harbour walls.
• Inspect for block shifting.
• Inspect for foundation undermining.
• Inspect for any abnormalities, holes etc.

Transnet Slipway Downhaul Pulley Change out x 2
• Locate downhaul pulley position.
• Dredge through 6m of mud to expose pulley.
• Remove the old pulley and install new designed pulley.
• Feed through 340 meters of cable through the pulley and onto the cradle of slipway.

Shipping CCTV Surveys
• CCTV GVI inspections.
• Propeller shining (hydraulic prop shiner)
• Cleaning of sea chests and overboard valves.
• Wear down readings on propeller shaft and rudder.
• Rope removal.
• Blanking of sea chests and overboard valves.
• Kettle patches.

Boat Salvage
• Inspect vessel for rigging points.
• Connect/ rig up lifting bags and steel lifting tanks to vessel.
• Floated vessel.
• Towed vessel to Transnet travel lift and removal.
• Cut up and safely disposed of the vessel.

Cutting of Pylons H&I
• Cut off and removed 40 steel pylons in the path of the fender construction.
• Hydraulic grinder was used to cut pylons.
• Full scale containerized dive systems were used.

Mossel Bay Slipway Structural Inspection
• Core drilled concrete samples out of slipway pile structure. Sent to lab for MPA and chlorine testing.
• Inspected pile structure for any damages or abnormalities.
• Inspected steel rails for extreme wear down and abnormalities.
• CCTV and still photograph survey on slipway structure, rails and pulley system.

Sandile Reservoir leak detection survey
• Full SSDE CCTV dive unit.
• Confined entry and exit.
• Full CCTV survey of inside seams of reservoir.
• Leak detected and fixed using underwater epoxy.

• GVI inspections
• Full CCTV hull surveys.
• Prop shaft and rudder shaft wear down readings.
• Hull cleans.
• Sea chest cleaning.
• Overboard lake cleaning.
• Remove rudder and pull propeller and shaft.
• Rope removals.
• Kettle patches installed.
• Greasing variable pitch propellers.
• Sea chest blanking.
• Overboard valve blanking.
• Stem tube sealing.
• Propeller scraping and hydraulic polishing.
• Trawling net removal.

Transnet Sand bypass System
• Securing and maintaining of Transnet sand bypass caisson pump system in Couga harbour.
• Removed 5m x 3m grid from aperture in caisson (removed by crane).
• Serviced 3 pumps from inside the caisson.
• Cleaned all marine growth within caisson.