RetroLink Sizing

Figures given assume the following typical values: seawater resistivity 25 ohm-cm, mud resistivity 75 ohm-cm, cathode potential -0.800V vs Ag/AgCl, current density 50 mA/m2.

System Components

RetroLink Strings: Shallow 30 ft, 5 anodes; intermediate 60 ft, 10 anodes; deepwater 90 ft, 15 anodes.

Leader Assembly: Standard 25 ft length (can be field adjusted). Coated wire rope with all hardware for either surface suspension with Topside Suspension Bracket, or subsea attachment with RetroClamp.

Topside Suspension Bracket: Allows topside suspension of RetroString may be electrically isolating for riser retrofits.

RetroClamp: Used for subsea attachment and electrical grounding to either jacket tubular or subsea pipeline.

V-String / SunStation: Integral monitoring system available for special applications.

Design Guide: Prints out a cathodic protection solution and a material list that can be priced with a simple e-mail or phone call to Farwest.

RetroLink installation.

Installation

A leader assembly is used for above-water suspensions and uses PVC-coated wire rope for corrosion resistance. The modular design allows the hang elevations to be easily adjusted in the field. The weld-on topside suspension assembly can be attached to horizontal or vertical members. The isolator can be used to have Links protect offshore risers. Links can be attached subsea using a modified hang-off. This allows the links to to provide large currents cost effectively to deeper water structures when a limited design life is adequate.

Applications

1. Minimal Offshore Structures
Many offshore structures that sit in less than 85 f.s.w can have the corrosion protection system replaced very cost effectively using RetroLink. The system can be quickly installed with a small topside crew. No diving is required. The system can provide 5 to 7 years of protection.

2. Offshore Wind Turbine
Foundation piles may be placed up to 1 year before the transition structure is installed. During this period RetroLinks can save the day, then can be recovered and redeployed during periods of grid power interruption. For quick, painless retrofit, this is the ideal system.

3. Docks, Harbors and Wharves
RetroLink systems are reliable and easy to maintain using small under-dock access vessels and equipment commonly found around such installations. A simple design guide enables the facility owner to apply adequate levels of cathodic protection following a simple field verification procedure. Links have been installed to provide cathodic protection to bridge pilings, whether reinforced concrete or steel. The installation is quick and easy.

4. Temporary Protection
Vessels in long-term wet storage can be protected cost-effectively by this system. Simple owner verification that submerged parts of the vessel are not corroding is possible with the optional inspection kit.

5. Pipeline Risers
Short infield lines can be effectively retrofitted with RetroLinks, using the host structure as the support and grounding to the pipeline side of the insulating flange.