Subsea

Rocksteady

Rocksteady® is an auto-latching subsea structural connector that is smaller and more capable than any other in its class.

Unparalleled reliability

The ROV locking mechanism is inspired by wellhead collet connectors, transferring the load to forged load shoulders and generating a high clamping force (or preload) in the mating parts.

Preload gives the Rocksteady subsea mooring connector unparalleled fatigue performance and the unique capability to accommodate bending, tension, shear and torsion loads.

Flexible

Rocksteady is qualified at any size up to 3,000t and in compact form factors for renewable energy systems.

The connector can also be supplied to suit a variety of interfaces including chain, shackles, rope sockets, articulating bearings and pipe weld necks.

We work closely with our sister company InterMoor for our mooring projects.

Applications

  • Acoustic remote disconnect of mooring lines (available through InterMoor)
  • MODU connection to prelaid moorings.
  • Subsea connections in permanently moored rigs and FPSOs.
  • Structural pile connections, including wind and wave power applications.

Advantages

  • Half the size & weight of other subsea mooring connectors, with associated cost benefit.
  • ABS & DNV qualification
  • Faster to install – automatic high speed latch, large guide funnel and 25° installation angle means you connect in rough seas.

Options

  • Remote control by acoustic (subsea) or radio (surface)
  • Lock status and tension data
  • Automatic lock following receptacle latch
  • ROV or diver manual override
  • Direct hydraulic

ROCKSTEADY is patented technology under European patent EP2800685 B1 and U.S. patent no. 10,144,488.
ROCKSTEADY is a Registered Trade Mark of Subsea Riser Products Limited.

Rocksteady QD

Rocksteady QD is our Quick Disconnect variant of the Rocksteady® subsea mooring connector, developed exclusively for our sister company InterMoor and available as the IM-Release.

It is used for rapid disconnection of mooring lines subsea, typically for weather and iceberg avoidance, or pre-lay mooring relocation, in MODU applications.

Rocksteady QD is equipped with a Teledyne Marine acoustic modem and an advanced control system developed by SRP, that monitors the connector condition and line tension, and releases each connector in a fraction of a second.

Advantages

  • R5 type approval
  • Release at any load: 900t MBL and 900t release capability
  • Modern touchscreen control
  • Compact size – quarter of the weight of our competitors
  • Release in groups, all together or in sequence

Security

  • Digital signal encryption
  • Unique addresses
  • Redundant release energy isolation

Reliability

  • Frequency hopping to avoid signal interference
  • 6km signal range (up to 10km)
  • Network relay mode
  • 5 year battery life

The 900t MBL connector is made for DNV GL OS E302 and ABS Chain Code R5 type approved material, enabling full class compliance of the mooring system.

We have completed a battery of release tests from 0% to 100% MBL, with a test program approved and witnessed by DNV and ABS. The connectors are now in production, please contact us to find out more.

ROCKSTEADY is patented technology under European patent EP2800685 B1 and U.S. patent no. 10,144,488.
ROCKSTEADY is a Registered Trade Mark of Subsea Riser Products Limited.

Rocksteady V

Rocksteady V is a variant of our field proven Rocksteady ® subsea mooring connector designed specifically for hull or pile mounting and pull through operations.

Rocksteady V can be integrated with one or more mooring lines in a range of configurations and it can be integrated with a range of commercially available wet mate connectors. This makes Rocksteady V ideal for renewables applications including floating wind, wave and tidal that require power offtake and rapid reconnection.

Rocksteady V during pull-in

Rocksteady V can be bolted down through, or up to the hull, enabling simple installation, replacement and servicing of the entire connector in dock.

SpecificationValue
MBL2500t
Other sizes and capabilities are available.
Size1340mm OD
Pull-through diameter400mm
Pull-in capacity15t (up to 100t)
Azimuth capture angle180° (full circle)
Auto-alignment angle15°
Latch capacity10% MBL
Time to lock15 seconds
(adjustable to suit demand)
Wet-mate connectorsIntegrate with OEM in annular area 368mm OD x 302mm ID
or horizontal secondary connection.
Mooring interfaceChain or rope, padeyes or bearings
Bearing optionsSwivel, trunnion, multiple

The connector capacity is verified with 3D finite element analysis, fatigue analysis and load testing. All components are manufactured from ABS and DNV approved mooring and structural materials, protected with field proven low friction and marine growth resistant coatings.

Rocksteady V automatically aligns the pull-in head and then automatically latches with capture angles up to 180° in azimuth (i.e. any orientation) and 15° offset from vertical. As with Rocksteady, the latch is virtually unaffected by heave motion or pull-in speed, enabling connection in any weather condition.

Lock is achieved hydraulically and the connector can be disconnected with tension in the mooring system, enabling rapid disconnection.

Rocksteady V connected and locked (vertical wet-mate stab plate removed for clarity)

The wet-mate connectors are mounted on a compliant stab plate, with further fine alignment available, enabling connection in a single movement. A secondary electrical connection action can also be accommodated owing to the fine azimuth and vertical alignment provided by Rocksteady V.

Rocksteady V has high bending capacity, which greatly simplifies pull-in and alignment operations, enabling catenary mooring systems to be pulled in vertically and orient to the anchor naturally.

Rocksteady V is capable of lateral loading

Contact us today for more information.

Bearing systems

Bearings are a cost effective method of limiting peak loads and fatigue damage in components subject to oscillating motions, such as in mooring lines and riser towers.

We conduct detailed FEA of bearings to predict wear, which is useful in high and eccentrically loaded applications, when the bearing manufacturer will not recommend use. We have also independently tested spherical and cylindrical bearings for use in oscillating subsea applications and can provide engineering support to integrate bearings in your system.

We can also package articulating bearings with the Rocksteady connector, which can withstand extreme cyclic bending loads; to provide a robust and reliable structural connection system.

Applications

  • Mooring line connections.
  • Hybrid riser tower pile and buoyancy can connections.
  • Riser storm hang-off.
  • Structural pile connections, including wind and wave power applications.

Advantages

  • Reduced capital cost: typically a bearing system will be less than half the price of an equivalent elastomer articulation system.
  • Quicker to deliver.
  • Simple design and shorter lead times.

Link Latch

Link latch is our economy subsea connector which is constructed almost entirely from fabricated plate materials.

Operational benefits include automatic azimuth alignment and latch, with manual lock and unlock with clear visual indication.

It is ideal for low tensile load, high shear load, and relatively static applications, or manufacture by a fabrication yard locally / in-country.

Link latch undergoing SIT prior to deployment in the North Sea in 2011
SpecificationValue
Load (tensile)Typically < 100t
Tested up to 2,000t
Water depthAny – unsealed
Corrosion protectionNORSOK System 7 paint, PTFE internally, cathodic protection
Azimuth capture45°, larger is possible
Azimuth alignment
Lateral tolerance1% of diameter
Lock / unlock methodROV torque bucket
Hydraulic motor
Electric motor

Link latch can be integrated directly to a hull, gravity base or pile structure; and as with any of SRP’s subsea connectors, we can integrate sensors, acoustic remote controls and complete automation.

SRP has designed and tested link latch up to 2,000t capacity