Survey and Inspection Archives - DUC Marine Group

Inspection Cooling Water Outlet

ducmarinegroup — Fri, 01 May 2020 10:43:03 +0000

The inspection of Cooling Water Outlet from the plant under the access channel to the Waddenzee-side.

For a client in the North of The Netherlands, DUC Marine Group had to perform an inspection of a cooling water outlet

The goal of the inspection was:

To assess over which length the pipeline is not filled with sand or sediments;
To assess the marine growth on the surface;
To determine visually the condition of the pipeline which was repaired earlier by DUC Marine Group;
To record the inspection real time on video;
To report the inspection;
To collect as much as possible information to estimate the costs for cleaning the pipe;
To collect samples of the mud for determining the quality for disposal;

The main safety issues in this project were:

The access on one side;
The length of 375 m of the pipeline;
The maximum depth of -/- 17 m datum NAP;
Confined space diving.

Together with our team of engineers, divers, safety officers and client, we managed to fullfill this project in one single safely controlled dive.

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Soil investigations

ducmarinegroup — Wed, 09 Nov 2016 15:39:15 +0000

SOIL INVESTIGATIONS

With our vessel RAM we successfully performed soil investigations near the coast of Den Helder.

In just two days we were able to fulfil the required assignment.

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Wall thickness measurements in Georgia

ducmarinegroup — Thu, 14 Jan 2016 15:54:49 +0000

WALL THICKNESS MEASUREMENTS IN GEORGIA

Georgia, Europe

At the end of 2011, DUC Marinegroup performed wall thickness measurements on a quay wall made of sheet piling with a cap. The quay wall was 360 metres long and measurements had to be taken at four places to a depth of 10 metres. Using a wall thickness meter, a diver took readings at the specified places.

Categories: Maintenance and Repair, Inshore, Non-Destructive Testing, Offshore, Preservation, Survey and Inspection

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Mauritanian iron ore jetty

ducmarinegroup — Thu, 14 Jan 2016 15:46:53 +0000

MAURITANIAN IRON ORE JETTY

Mauritania, Africa

During a five-year project, DUC Marinegroup performed maintenance to an iron ore jetty in Mauritania, Africa.

The jetty was protected by anodes that had to be checked. As anodes decay in the course of time, regular maintenance and repair is necessary.

DUC Marinegroup has its own equipment to carry this out, including C.P. meters and wall thickness meters for use under water. Anodes that did not function correctly were replaced or additional anodes were installed.

Categories: Maintenance and Repair, Inshore, Offshore, Cathodic Protection, Civil Underwater Construction, Non-Destructive Testing, Preservation

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Inspect, testing and replacing of anodes

ducmarinegroup — Thu, 14 Jan 2016 15:37:34 +0000

INSPECT, TEST AND IF REQUIRED REPLACE ANODES

Port of Rotterdam and Amsterdam, The Netherlands

In the Port of Rotterdam and Amsterdam, DUC Marine Group regularly checks anodes and replaces them if necessary. Not only in the Netherlands we inspect and replace anodes but all over the world. Regular exchanging of anodes are performed in United Kingdom, Africa and Europe.

Categories: Maintenance and Repairs, Inshore, Offshore, Non-Destructive Testing, Survey and Inspection, Cathodic Protection, Civil Underwater Construction

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Burial of a cable loop

ducmarinegroup — Tue, 22 Dec 2015 15:22:38 +0000

BURIAL OF A CABLE LOOP

Windpark DanTysk, German Economic Zone.

The DanTysk wind farm is located approx. 70 km west of the North Sea island of Sylt. The 80 wind turbines, each with a power output of up to 3.6 MW, are installed in a water depth of between 21 and 31 m in the Federal Republic of Germany exclusive economic zone.

During the cable installation operation for cable 7.10, a loop formed in the cable on the seabed approximately 150m west of the OSS, towards Transition Piece (TP) 75.
An ROV survey was carried out on the cable and the loop was found to be approximately 6.5m x 4.4m, creating a bend radius of approximately 2.2m.

DUC Marinegroup was requested to form a Method Statement for securing trenching a cable loop approximately 1 – 1,5m into the seabed at their project in the Wind farm ‘Dan Tysk’. It was vital to the preservation of the cable integrity that the radius of the loop kept stabilised and prevented from reducing.

Categories: Cable Burial, Offshore, Renewables, Wind Park, Survey and Inspection

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Grout lines removed

ducmarinegroup — Tue, 22 Dec 2015 08:49:56 +0000

GROUT LINES 28.4 KM REMOVED

Contract
In the middle of August 2013 DUC Marinegroup received a contract from RWE Innogy, for works on the offshore windfarm Nordsee Ost, located some 30 km North-East of the Island of Heligoland in the German Bight. The contract comprised the removal of temporary grout and hydraulic lines, which were utilized during the installation of 49 offshore foundation jackets during the winter season in the North Sea.

The jackets were installed for the later mounting of the 6 megawatt turbines. The hoses run from a service station at the top of the jacket (25 m above MSL), on the outside of the structure over the bracings to the foundation sleeves at the bottom (25 m below MSL). A typical jacket was fitted with 4 hydraulic lines and 8 grout lines.

Partnership
For the industrial climbing works DUC Marinegroup teamed up with the Rope Access Group from the Netherlands. It proved to be a very fruitful partnership between DUC and the Rope Access Group teams, to be continued again.

Personnel and equipment
Directly after signing the contract a project team was set up and work preparations commenced. Instead of a DP-2 vessel DUC chose to deploy a big multicat to be converted into a dive support vessel. In less than three weeks DUC mobilized the following:
–   A full Rope Access Team;
–   A crew transport vessel;
–   A full dive team;
–   A dive support vessel with a three point mooring, a LARS-system, a combined dive control/deco container, a nitrox container, 3 extra TLQ’s with 8 persons capacity and an office;
–   A 10 m RIB with a SRS-system.

Home port for the operations was the island of Heligoland. In the south-harbour a temporary stockpile was set up to store the removed hoses. Whenever possible, the dive support vessel stayed offshore and divers worked in 24-7 shifts, whereas the Rope Access team worked 12 hr shifts and sailed every day by CTV to and from Heligoland.

The grout lines were left partly filled with grout. The hydraulic lines still contained hydraulic oil. Before cutting the hydraulic lines all underwater valves had to be opened by the divers. The RAT-team flushed the lines with fresh water and detergent. All out coming fluids were collected and disposed. The service stations were then removed.
In total DUC had to remove some 28.4 km of hoses. The divers and the RAT-team used special hydraulic tools to cut the lines in easy manageable lengths, which were then stored in skips onboard the dive support vessel.

Satisfied by the accomplished work DUC Marine Group was assigned – during the job by RWE Innogy to carry out extra diving activities in the wind farm:
– The installation of several sonar- and motion transponders;
– The removal of debris in the proposed cable array;
– Inspection of several J-tube bellmouths;
– Inspection – and repairs of gratings, railings etc. after recent storm damage.
During the project the DUC fleet increased. During the busiest period DUC was in Heligoland with two dive support vessels, two dive teams, three CTV’s, an anchor handling tug and two RAT-teams.
Logistically, DUC Marine Group faced a lot of downtime due to inclement weather conditions during the winter working season.
However the project was successfully completed in good time and much quicker than anticipated, without any injuries and to the full satisfaction of our client RWE Innogy.

Categories: Offshore, Maitenance and Repairs, Offshore Construction and Installation, Renewables, Rope Access, Survey and Inspection, Wind Park

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