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RetroSled overview

RetroSled™
Aluminum anode sled for pipelines

The RetroSled allows operators to replace cathodic protection anodes on aging pipelines.

The RetroSled is an aluminum anode sled, designed for offshore pipeline life-extension projects. The RetroSled itself is lowered onto the sea floor via crane and then connected electrically to the pipeline with one or two RetroClamps. Anode sled retrofit sites along the pipeline are determined by our cathodic protection designers using recent survey data and Deepwater's PipeMod™ cathodic protection modeling system. Accommodating seabed conditions and pipeline burial, our engineers pick spots that maximize cathodic protection potentials while minimizing the number of installation sites required.

Versatile in design - A cathodic protection retrofit project conducted using the RetroSled system can add between 15 and 30 years to the life of an existing pipeline, depending on existing CP potentials and the needs of the operator. The RetroSled is available in two versions: the standard, rigid sled and an expandable version, which opens once lowered to the seabed. The expanding sled is used to more immediately re-polarize a pipeline with dangerously low cathodic protection readings; the standard sled is employed for pipelines with depleted andes, but which are still adequately protected. Both sled models can be installed by diver or ROV.

A reliable connection - The RetroClamp is patented technology, developed at Deepwater and available nowhere else. The RetroClamp connects to the RetroSled by two armored cables to the pipeline it is intended to protect. The Clamp is diver and ROV-friendly. The contact tip of the clamp that creates electrical contact with the pipeline can be fitted with a soft drill bit, allowing it to penetrate concrete weight coats. The floating plate on the top of the clamp ensures a strong and constant connection that will not damage the pipe. The ease with which it is installed makes the RetroClamp incredibly cost-effective in comparison to underwater welding or other attachment methods. For a buried Pipeline, only a percentage of the pipeline must be visible for a diver to install the RetroClamp.


Applications

Offshore pipelines

In shallow-water situations, a diver can quickly attach RetroClamps to the pipeline. Buried pipelines must be partially excavated. For deep-water applications, the ROV can install the RetroClamp with a fishtail handle rather than the standard T-handles used by divers. The expanding sled is deployed closed and later opened via crane or ROV once on the seabed. It uses the same clamps for attachment as the rigid sled.

Risers

For riser protection near a fixed structure when the riser is isolated electrically from the rest of the platform, the RetroSled can be clamped to the desired section of the riser.

RetroSled aluminum anode sled Expanding RetroSled aluminum anode Expanded Retrosled (aka ExpandaSled) shown on bottom Aluminum pipeline anode sled offshore RetroSled being loaded in the Gulf of Mexico, circa 2002 Aluminum anode retrofit sleds for pipeline cathodic protection RetroSled with RetroClamp attached, prior to deployment in the North Sea in the Forties field Rigid RetroSled being loaded from a flatbed onto a vessel Expanding aluminum anode sled being opened on the sea floor via crane (depth 200 ft.) ExpandaSled (expanding RetroSled) being deployed topside from a support vessel
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Key design points

Reduce the intervention during installation

The Sled can be rapidly and safely deployed offshore, with little to no diver intervention. RetroClamps are fully ROV-installable.

A proven design

RetroSled has been installed by major operators in every market area worldwide. Thousands of miles of pipeline have been successfully retrofitted with our anode sleds.

Rigid and expandable versions

Use the standard RetroSled when extending life on a pipeline with good coating and readings that indicate it’s still protected (above (-) 0.900 V vs. Ag/AgCl sw). Use the expanding sled when an extra current boost is required for a depolarized pipeline or one with degraded coating. Both models of RetroSled ship via normal trucks and containers. The expanding sled is deployed closed and opened via crane or ROV once on the seabed.

Quality control

All of the anodes that Deepwater provides are manufactured at one of our ISO 9000-certified foundries. Each foundry is located just minutes from the engineers and designers managing our projects, allowing Deepwater to oversee QA/QC on every anode.

Video

Watch a RetroSled being deployed offshore in the North Sea as part of a retrofit project for the in-field flowlines of the Forties field.