Subsea Connectors

How each connector type seals

• Electrical wet-mate connectors keep their contacts in oil-filled, pressure-compensated chambers. As the halves mate, the pins pass through wiper seals that clear seawater off them, and the insulating oil keeps the contacts dry.
• Optical wet-mate connectors use the same principle for fibre contacts. They are more sensitive to contamination, because a speck on a fibre end adds loss.
• Hydraulic couplers are male and female poppet halves that open as they engage. A multi-way stab plate aligns many couplers and connectors at once and is landed by an ROV or with a module.
• Flowline and jumper connectors lock a pipe end onto a hub with collet fingers or clamp segments and seal with a metal gasket. They are actuated hydraulically or by an ROV torque tool.

Configurations

• Wet-mate electrical connectors for power or signal, including flying leads with a connector at each end.
• Optical and hybrid electro-optical wet-mates.
• Single hydraulic couplers and multi-way stab plates.
• Vertical and horizontal flowline tie-in connectors, collet or clamp type.

Key specifications

Standards and certification

• API 17F, aligned with ISO 13628-6, is the standard connector makers qualify electrical and optical wet-mates to, including hyperbaric testing. Ask for the qualification report for the series.
• API RP 17R covers the design and testing of flowline connectors and jumpers.
• API RP 17H sets the ROV interfaces on connectors, such as torque buckets on clamp drives and handles on flying lead terminations.

Failure modes and inspection

On wet-mate connectors:

• Seawater ingress through worn wiper seals or a cracked shell, which ends the connector's life.
• Pin and socket corrosion, bent pins and lost compensating oil.
• Calcareous deposits on recovered halves that block mating.

Test insulation resistance at the maker's test voltage, contact resistance and continuity, and optical insertion loss. Inspect pins and seals under magnification.

On flowline connectors:

• Scratches, pitting or corrosion on hub and connector sealing faces.
• Cracked collet fingers or clamp segments. Use dye penetrant or magnetic particle testing.
• A worn or seized locking mechanism.

Check sealing faces dimensionally against OEM limits, and hydrotest the made-up connection.

On hydraulic couplers, check poppet seat leakage, seal wear and fluid cleanliness with a pressure test.

Documentation

• A mate count log for every wet-mate half.
• Qualification and FAT reports for the series.
• Insulation resistance and continuity history.
• Storage records confirming protective caps stayed fitted.
• Material certificates and hydrotest records for flowline connectors.
• The gasket part number and the OEM's make-up procedure.

Integration

A wet-mate half must match the installed series, shell size, pin layout and oil type. Flying leads must reach between terminations with the right length and bend radius. Couplers must suit the field's control fluid and the subsea control modules they serve. Flowline connectors must match the hub profile, gasket, tie-in tool and the ROV torque class that drives them.

Refurbishment, used or unused surplus

Wet-mate connectors are refurbished by their maker, who replaces seals, refills oil and repeats the electrical or optical tests. Flowline connectors are refurbished to the OEM's procedure, with sealing surface repairs held to its limits and a new gasket and pressure test. Unused surplus connectors with intact caps are the safest buy. Used wet-mates are worth buying only with a known mate count and clean test results.

Teledyne Marine (ODI and D.G. O'Brien) and TE Connectivity (SEACON) are major wet-mate makers. Flowline connection systems come from TechnipFMC, OneSubsea (SLB), Oceaneering and Baker Hughes.

ROV tools that make up these connections are in subsea tools and intervention.