V-String™ zinc reference electrode
V-String has a rugged conductor with a strong overbraid of polyester fibers for monitoring platform CP
The V-String™ zinc reference electrode has a rugged conductor with a strong overbraid of polyester fibers
The Polatrak® V-String™ electrode is a low-cost zinc reference electrode designed for offshore platform and pipeline monitoring. The ultra-rugged construction and ease of installation make this a viable general-purpose cathodic-protection monitoring retrofit system, or as a supplement to other Polatrak® monitoring instruments such as the DR-2™ dual reference cell, or the MA-1™ monitored sacrificial anode. The V-String's accuracy is +/- 0.02 V, which is perfectly acceptable for a general-performance monitor.
The electrode wire consists of a galvanized-steel aircraft cord with a PVC jacket and a polyester-fiber overbraid. This combination makes the electrode almost indestructible. V-Strings™ have been installed on dozens of types of structures, from platforms and offshore pipelines to shallow-water wind farms.
Interrogating the electrode can be done in several ways. If installed on a traditional structure, the conductor can be wired to the surface and connected to a monitoring panel. In some instances, the panel can also be wired to a satellite transmitter. For subsea assets and offshore pipelines, the V-String™ can be interrogated by ROV using a SunStation™ subsea readout.
Project experience
PanYu 30-1
Project case study: ICCP anode retrofit for eight-leg structure in the South China Sea
- Water depth: 200 m
- Fixed monitoring
Tubular Bells
Project case study: Anode retrofit for production pipelines in Mississippi Canyon
- Water depth: 4,500 ft
- Installation: ROV
Zafiro Producer
Project case study: Impressed current cathodic protection of FPSO hull
- Water depth: 590 ft
- Dynamic cable
- 800 Amps CP
Ship Shoal structures
Project case study: RetroLink™ anode strings on shallow-water assets in the Gulf of Mexico
- 64 RetroLinks™
- 25 structures
RetroLinks protect Gulf of Mexico platform
- 44 RetroLinks™ installed
- Anode string length: 200 feet
Dock Cathodic Protection
Anodes systems for Docks, Jetties and Piers
Kitchen Lights
Project case study: ICCP anode system for a new platform in Alaska
- New fixed jacket
- Cook Inlet, Alaska
- Impressed current
The cost of a bad pipe support
Houston Ship Channel dock
Project case study: Houston Ship Channel retrofit
- 5 docks protected
- Installation: Divers
- 47 RetroLinks™ installed
- 16 ICCP anodes installed
Tapis-F & Irong Barat B
Project case study: Anodes replaced on two Malaysian platforms
- Fixed platforms
- Installation: ROV
- Install time: 63 hrs
California wave park survey
Project case study: California wave park corrosion survey
- CVI/NDT inspection Done
- 500,000 sq. ft. + facility
- 55+ assets Inspected
- ICCP retrofit recommended
Montara CP test stations
Montara Pipeline fitted with CP test stations
- Wellhead trees and PLET needed electrical continuity
- Piggybacks on flowlines lacked continuity
- Tiebacks were used to ensure electrical continuity
- RetroClamp™ CP test stations were added
Hydrogen embrittlement study
Project Case Study: Hydrogen Embrittlement Study
- Study focused on clamp connector
- Possible gasket embrittlement from CP
- Internal sections of clamp monitored for CP
- Polarization of gasket could generate hydrogen
Offshore wind farm
Project case study: ICCP anode sled to supplement failing anodes on 33 wind turbines
- Field: 33 tripod turbines
- Install: < 24 hrs / turbine
Leman Alpha
Project case study: ICCP anode sled to supplement failing anodes on three structures
- Install: 12 hours per buoy
- Depth: 35 M
- 25-year design life
TAQA North Cormorant
Impressed Current Cathodic Protection (ICCP) retrofit on the North Cormorant Platform
- Fixed platforms
- Installation: ROV
- Install time: 18 hrs
Tabu, Guntong, Semangkok
Project case study: Anodes replaced during pipeline survey campaign
- 3 pipelines
- Installation: ROV
- Install time: 4 days
Offshore drill stack
Project case study: CP levels monitored and corrected
- Recap Datalogger
- CP & Coating Remediation
6 Bay Marchand platforms
Project case study: Anode retrofit of 6 Bay Marchand platforms
- 6 structures
- 61 anode strings
- 5 year life extension
Joliet TLP
Project case study: Anode retrofit for the foundation template of a TLWP in Green Canyon
- Water depth: 1,760 ft
- 19 x RetroPods™
Cathodic protection sleds
Heavy-duty anode sleds for high water currents
- Heavy duty, lower profile sleds
- For high water current environments
- High-strength piping
- 20-year design life
Frying Pan Tower
Project case study: Offshore bed and breakfast platform anode retrofit
- Civilian owned
- 12 RetroLinks™
Green Canyon
Project case study: Anode sleds installed at Neptune and Shenzi fields
- Water depth: 4,400 ft
- Install time: 3 days
Brent pipeline
Project case study: Pipeline anode retrofit with mattresses
- 12 km pipeline
- Conctrete weight coat
- 15 year life extension
Garden Banks 191-A Anode retrofit
Project case study: ICCP anode sleds retrofit on a GOM fixed platform
- Water depth: 720 ft
- Installation: ROV
- Install time: 2 days
Shenzi subsea tree
Project case study: SunStation CP monitoring system interrogated by ROV at 4,300 ft
- Water depth: 4,300 ft
- 25-year monitoring system
- No batteries required
GOM structures
Project case study: Cathodic protection retrofit on five structures in fourteen days
- 5 fixed jackets
- Install time: 14 days
- 210' four point boat
Arnold / Oyster fields
Project case study: Anode retrofit on two deep-water subsea fields in the Gulf of Mexico
- Installation: ROV
- Install time: 72 hours
- Depth: 775 ft / 1,750 ft
Forties field flowlines
Project Case Study: Anode retrofit for the in-field flowlines in the North Sea
- Install time: 60 hours
- Depth: 106 m
Duncan Wharf
Project case study: Cathodic protection retrofit using impressed current anode sleds
- Semi-Arctic temperatures
- 3,700 AMPS of CP
Cook Inlet Pier
Project case study: Deepwater designs and installs new impressed current pile anode in Alaska.
- 1,800 AMPS of CP
- Freeze / thaw resistant
Bahamas loading dock
Project case study: Failing dock anodes replaces with topside anode strings
- Sacrificial anodes
- Diverless install
Alba Field
Project Case Study: Anode replacement on a pipeline in EG
- Installation: ROV
- Depth: 200 ft
- Sacrificial anode sled
Neptune Spar
Project Case Study: ICCP anode sled to supplement failing anodes on the hull
- INSTALL TIME: 72 HOURS
- DEPTH: 1,930 FT
- 15 YEAR DESIGN LIFE
Arklow Bank
Project case study: ICCP anode system for wind farms in the Irish Sea
- 7 x wind turbines
- Water depth: 10 m
- Offshore time: 11 days
Ras Gharib platform
Project case study: Retrofit anode sleds for a fixed platform in the Red Sea
- Install: Divers
- Install time: 24 hours
- Depth: 14 m
- As left: (-)1.050V vs Ag/AgCl
Lufeng 13-2
Project case study: Two RetroBuoy™ systems for a fixed platform in the South China Sea
- Platform installed 2005
- Premature anode failure
- Depth: 430 ft
- Supplemental ICCP anodes
Forties Field platforms
Project case study: Nine RetroBuoy™ systems installed to protect four aging North Sea structures.
- 4 fixed platforms
- 9 x 450 Amp sleds
- Install: 12 hours each
- 20-year design life
South Pass 62-C
Project case study: Two RetroBuoy™ systems replace spent anodes on a 330 ft platform in the Gulf of Mexico
- Install time: 30 hours
- Depth: 330 ft
- 20 YEAR DESIGN LIFE
Black Bay platforms
Project case study: Anode strings retrofit on 69 structures in Black Bay, Gulf of Mexico
- 115 anode strings
- 22 continuity jumpers
- Structures: 69
- Offshore time: 22 days
24 inch methanol pipeline
Project case study: RetroMat™ anode sleds installed on the Atlantic methanol pipeline in EG
- Local assembly
- Offshore time: 3 days
- Length: 2 km
- As left: -1.025V vs Ag/AgC
Chinook Field PLET
Project case study: Deepwater designs a mini-gateway retrofit in the Gulf of Mexico
- Continuity jumper
- Borrowed CP from PLET
- Custom design
- 2 week turnaround
Eugene Island 295-A
Project case study: Spent platform anodes replaced with subsea anode strings by divers
- Installation: Divers
- Install time: 60 hours
- Depth: 220 ft
LAF-1 & 2 Platforms
Project case study: Single float RetroBuoy™ systems installed in the Gulf of Guinea.
- Installation: ROV
- Impressed current anodes
ERWB Jackets
Project case study: Seabed anode sleds retrofit CP on Gulf of Thailand platforms
- Bridge-connected jackets
- Water depth: 200 ft
- Install time: 60 hours
- Seabed anodes only
Ewing Bank 305-A
Project case study: Two large impressed-current anode sleds installed on a GOM platform
- Water depth: 300 ft
- 20 year life extension
- 800 Amps of CP current
Olympus Field PBGs
Project case study: Self-monitored anode sled protects 24 new PGBs at 3,000 ft for 45 years.
- Installation: ROV
- Install time: 30 hours
- Battery-free monitoring
- 45-year design life
Liverpool Bay OSI
Project case study: Hanging ICCP anode system installed to protect the hull of a floating storage vessel
- Installation: Topside
- Offshore time: 4 days
- Unit is storm-recoverable
- 10 year life extension
Tamar Field
8 inch pipeline
Project case study: RetroLink™ anode strings used to retrofit cathodic protection on 8 inch pipeline
- Installation: Divers
- Offshore time: 30 hours
- Length: 4.5 km
- As left: -0.998V vs Ag/AgCl
Dudgeon OWF
Project case study: Remote cathodic protection monitoring system installed in the North Sea
- 4 offshore turbines
- 32 km offshore
Dana Triton FPSO retrofit
Project case study: Hanging ICCP anode system installed to protect the hull of a floating storage vessel
- Installation: Topside
- Unit is storm-recoverable
- Remote O&M
BARD Offshore 1 OSS retrofit
Project case study: RetroBuoy™ ICCP anode system for an OSS transformer platform
- Platform installed 2010
- Premature anode failure
- 25-year design life
Pipeline Excavation Tool (PET™) installs RetroClamp™
Excavation of shallow buried underwater pipeline near Grand Isle, LA
- Entire operation done from topside - no divers
- Took two hours to excavate and install RetroClamp™
- Whole operation including setup and demob took one day
Case study: Sendje Ceiba FPSO outfitted with RetroBuoy™ ICCP sled
Project case study: RetroBuoy™ ICCP anode system installed to protect the hull of a floating storage vessel
- Up to 500 amps for 20 years
- Initial current required: 190 amps
- Final current required: 404 amps
Gunfleet Sands wind farm anodes
38 monopiles retrofit in Gunfleet Sands
- 38 monopiles retrofitted in Gunfleet Sands
- Monitoring added to 6 Gunfleet Sands monopiles
- Monopile in Lincs gets CP retrofit and monitoring
Enterprise dock anodes
SACP retrofit of dock structure and pilings in Beaumont, Texas
- Sections of dock, dolphins and piles had insufficient CP
- Anodes added to supplement existing land-side ICCP
- Continuity cables added to discontinuous sections
LINCS wind farm monitoring
Monitoring systems for wind monopiles
- Wind monopiles without internal coating or CP
- Long-term monitoring on sampling of structures
- Corrosion coupons measure wall loss over time
- Electrical resistance system logs data
Sheringham Shoal anode strings
RetroLink™ anode string tested on wind farm monopile
- Inadequate CP on external sections of pile
- Retrofit couldn't use divers or welding
- RetroLinks™ attached to custom clamps
- Current monitoring and reference electrodes added
Port of Alaska dock
Cathodic protection retrofit for beams
- 8 Raparound™ anodes used
- Divers secured anodes and routed cables
Who Dat retrofit with suspended ICCP anodes
Semi-submersible rig needed short-term CP
- Most existing ICCP anodes had failed
- Suspended anode chosen as fastest, lowest-cost option
- Existing transformer/rectifier used
- Suspended anode is tethered to prevent damage
RetroLink™ anode strings installed
Apache’s EC-2-C 4-pile structure in the Gulf of Mexico
- Six RetroLink™ anode strings installed
- Depth: 30 feet of water
- Located in Gulf of Mexico
- Total time - including travel - 6 hours
Galveston Island Historic Pleasure Pier retrofit
47 RetroLink™ anode strings installed
- RetroLink™ anode strings installed
- Anode strings attached with RetroClamps™
- CP levels verified using Polatrak ®CP Gun™
RetroPods™ installed on wellheads and SUTA
Three anode sleds protect subsea equipment
- RetroPod™ anode sleds installed
- RetroClamps™ provide electrical connection
CP jumper system installed on pipeline
Jumper system provides CP bridge across insulator joint
- Two 12” RetroClamps™ were installed
- Pair of 4/0 cables provide continuity
- ROV installation
ReCap™ data logger installed on BOP stack
Can log CP data for 4 years at 3,000 meter depths
- System includes high - impedance data logger
- Two V-String™ zinc reference electrodes used
- Data recorded every 15 minutes for four years
- Non-stop data logging of two independent channels
Four platforms retrofit near Trinidad
59 anode sleds, 3 clamp-on anodes used
- 59 anode sleds were required
- 3 Dual-anode clamp-ons were used
- Smaller booster anodes added to top of sleds
- Systems were connected via RetroClamps™
RetroLinks™ installed on multiple assets
Chevron needed CP retrofits on smaller Gulf of Mexico structures
- A total of five RetroLinks™ installed
- Platforms, wellheads and pipeline risers
- Assets spread over various fields
RetroLinks™ installed on Boardwalk Pipeline
Retrofit of shallow pipeline in swamp with RetroLinks™ and RetroClamps™
- 490 feet of RetroLinks™ installed
- RetroClamps™ attach anodes to pipeline
- RetroReader™ used to confirm connection
Anode sled installed on fixed-jacket platform
Sled replaced anodes removed during construction
- Anode sled was attached via RetroClamp™
- Saturation divers used to place sled
Anodes installed in chemical plant storage tank
Monitoring system also installed
- 12 weld-on zinc based anodes installed
- Potential monitoring panel using zinc reference electrodes was installed
Four RetroSleds™ installed on two pipelines
One installed on 10" line, three on a 6" line
- Installed from jack-up boat
- Divers helped place the sleds
- In Gulf of Mexico, south of Louisiana
RetroLinks™ installed on Chevron East platform
23 RetroLink™ anode strings were attached
- RetroLinks™ were attached to 23 horizontal stand-offs
- Caisson structure in 48 feet of seawater
- Two Vamp Clamps™ used for electrical continuity
- 1.5 hours average installation time per anode string
RetroPods™ installed on ExxonMobil platforms in South China Sea
Guntong-F and Irong Barat-C platforms retrofit with RetroPods™
- Two platforms retrofit
- 36 RetroPods™ total installed on two platforms
- Assets in 63 meters of seawater
Retrolinks™ installed on three platforms
Arenque A, B and C get CP retrofits
- 20 Retrolinks™ used per structure
- Retrolinks™ were 200 feet in length
- Protected for at least 5 years
RetroSled™ installed on subsea pipeline
6" pipeline in the Gulf of Mexico
- Pipeline near Renaissance MP 76 platform
- RetroSled™ used to provide CP
- RetroClamp™ provides electrical connection
- Located in the Gulf of Mexico
Buffalo Bayou sheet pile survey
Corrosion survey of steel sheet piles in downtown Houston waterway
- Survey of submerged steel sheet piles
- Identify multiple discontinuities along piles
- 6 of 7 TRs were functioning
- Sampled mud and water for resistivity
160 km pipeline, platform, flare tower retrofit
Located in the Gulf of Thailand
- 81 RetroSleds™ and 162 RetroClamps™
- 13 Test stations installed
- RetroMat-CP Test Station™ used on buried pipeline
CP monitoring installed on marine fueling dock
Açu Maritime Fuel Terminal - TECMA north of Rio de Janeiro State
- 8 V-String™ reference electrodes and monitoring panel
- Berth 1: 185m X 32m
- Berth 2: 110m X 21m
Monitoring system for Australian pipeline
SunStation™, V-String™ and MA-1™ will monitor pipeline and hardware
- SunStation™ will monitor pipeline CP
- V-String™ reference electrode attached to SunStation™
- MA-1™ will monitor Spool Connection Assembly
RetroLinks™ installed on smaller Gulf of Mexico structure
Quarter North Energy’s SS-80A
- RetroLink™ anode strings installed
- RetroLinks attached to stand-offs welded to structure
- Smaller structure in Gulf of Mexico
- Water depth: 25 feet
CP simulation on an offshore platform
CP modeling was used to provide depolarization timeline
- Inspection CP data used
- 3D CAD model used
- North Sea simulation
Riser base CP modeling
Modeling used to verify 15-year life extension
- Developed 3D CAD model of asset
- Used existing CP survey data
- 15-year life extension
RetroPods™ installed on FPU subsea equipment
Wellheads and gravity bases protected by RetroPods™
- 12 RetroPods™ and 18 Web-RetroClamps™ installed
- 10-year life extension
- 115 meter water depth
Arabian Gulf pipeline CP retrofit
- 25 RetroClamps™ deployed
- 8-inch pipeline from wellhead platform
- Used to electrically connect anode sleds
64 RetroLinks™ installed on pipelines
- 64 RetroLinks™ used
- 26 RetroClamps™ used to attach links
- Anode strings laid on seabed
Deepwater installs RetroSleds™ to protect two pipelines
- 2 RetroSleds™ and 4 RetroClamps™ on 8" pipeline
- 1 RetroSled™ and 2 RetroClamps™ on 12" pipeline
- Pipelines at 210' and 220' depth
RetroLinks™ installed on small structure
- 14 RetroLinks™ installed
- 66" lengths
- Gulf of Mexico
PET™ pipeline excavation and clamp installation
- 48" and 30" pipelines under 4' to 6' of mud
- PET™ used to excavate pipes
- Two RetroClamps™ installed
- Excavation time: 2 hours
20 RetroLinks™ installed in Gulf of Mexico
- 20 RetroLinks™ installed
- 150-foot RetroLink™ length
- Water depth: 148 feet
I-Rod® 28 years after installation
Harmony, Heritage and Hondo
- Depths: 850 ft to 1,200 ft
- Install: 21 Retrobuoys™ in 17 days
- 25-year design life