Way Ahead In Corrosion Control

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

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

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

Dudgeon OWF

Project case study: Remote cathodic protection monitoring system installed in the North Sea

  • 4 offshore turbines
  • 32 km offshore

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

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

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

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

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

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

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

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™

PanYu 30-1

Project case study: ICCP anode retrofit for eight-leg structure in the South China Sea

  • Water depth: 200 m
  • Fixed monitoring

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

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

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

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

Offshore drill stack

Project case study: CP levels monitored and corrected

  • Recap Datalogger
  • CP & Coating Remediation

Tubular Bells

Project case study: Anode retrofit for production pipelines in Mississippi Canyon

  • Water depth: 4,500 ft
  • Installation: ROV

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

RetroPods™ installed on wellheads and SUTA

Three anode sleds protect subsea equipment

  • RetroPod™ anode sleds installed
  • RetroClamps™ provide electrical connection

Zafiro Producer

Project case study: Impressed current cathodic protection of FPSO hull

  • Water depth: 590 ft
  • Dynamic cable
  • 800 Amps CP

Neptune Spar

Project Case Study: ICCP anode sled to supplement failing anodes on the hull

  • DEPTH: 1,930 FT

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

Green Canyon

Project case study: Anode sleds installed at Neptune and Shenzi fields

  • Water depth: 4,400 ft
  • Install time: 3 days

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

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

LAF-1 & 2 Platforms

Project case study: Single float RetroBuoy™ systems installed in the Gulf of Guinea.

  • Installation: ROV
  • Impressed current anodes

Duncan Wharf

Project case study: Cathodic protection retrofit using impressed current anode sleds

  • Semi-Arctic temperatures
  • 3,700 AMPS of CP

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

Dock Cathodic Protection

Anodes systems for Docks, Jetties and Piers

TAQA North Cormorant

Impressed Current Cathodic Protection (ICCP) retrofit on the North Cormorant Platform

  • Fixed platforms
  • Installation: ROV
  • Install time: 18 hrs

6 Bay Marchand platforms

Project case study: Anode retrofit of 6 Bay Marchand platforms

  • 6 structures
  • 61 anode strings
  • 5 year life extension

Ship Shoal structures

Project case study: RetroLink™ anode strings on shallow-water assets in the Gulf of Mexico

  • 64 RetroLinks™
  • 25 structures

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

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

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

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

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

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

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

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

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

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

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

Frying Pan Tower

Project case study: Offshore bed and breakfast platform anode retrofit

  • Civilian owned
  • 12 RetroLinks™

Garden Banks 191 A

Project case study: ICCP anode sleds retrofit on a GOM fixed platform

  • Water depth: 720 ft
  • Installation: ROV
  • Install time: 2 days

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

Kitchen Lights

Project case study: ICCP anode system for a new platform in Alaska

  • New fixed jacket
  • Cook Inlet, Alaska
  • Impressed current

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

I-Rod® 28 years after installation

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

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

Port of Alaska dock

Cathodic protection retrofit for beams

  • 8 Raparound™ anodes used
  • Divers secured anodes and routed cables

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

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

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

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

Tabu, Guntong, Semangkok

Project case study: Anodes replaced during pipeline survey campaign

  • 3 pipelines
  • Installation: ROV
  • Install time: 4 days

Brent pipeline

Project case study: Pipeline anode retrofit with mattresses

  • 12 km pipeline
  • Conctrete weight coat
  • 15 year life extension

Forties field flowlines

Project Case Study: Anode retrofit for the in-field flowlines in the North Sea

  • Install time: 60 hours
  • Depth: 106 m

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

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

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™

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

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

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

No related download nodes

Related content