Single Anchor Loading

A lower-cost alternative to the STL system for use in situations in which traditional catenary anchor leg mooring (CALM) buoys cannot be used. 

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Description

A Single Anchor Loading (SAL™) base anchored into the seabed integrates the pipeline end manifold (PLEM), a mooring turret, and in-line swivel. An oil-loading tanker (OLT) or floating storage and offloading (FSO) vessel freely weathervanes around the SAL subsea turret via a mooring polyester rope. The mooring includes a clump weight that provides damping. The oil is transferred through an in-line swivel and a hose string assembly up to the vessel piping at the bow. OLTs may gain efficiency with the addition of a complete Bow Loading System (BLS); FSO vessels simply require minor bow piping manifold addition. A quick connect/disconnect coupler provides safety against oil spill risk while a weak link in the chaffing chain provides for mooring release beyond a set threshold.

Advantages

Connection and disconnection on the SAL takes only a couple of hours and can be performed in seas as high as 4.5 m Hs for connection and 7 m for disconnection. Since the SAL is subsea, the risk of collision between the tanker and traditional CALM buoy is eliminated. Finally, the SAL mooring and hose string assembly can be abandoned clear of the vessel to lie on the seabed, well protected.

Permanent or disconnect mooring

The SAL system can be designed for disconnected service (i.e., OLT or shuttles) or for permanent mooring throughout the field life (i.e., FSO unit).

SAL integration

The vessel modifications are limited to either bow piping manifold addition or to the addition of a standard North Sea bow loading system. All equipment used to operate the SAL system are remotely controlled and monitored.

SAL system references

Our SAL systems cover a wide range of applications, from the harsh North Sea environment to ice-covered areas like Arctic Russia.

SAL in ice

Icebergs and ice ridges in Arctic environments are better addressed with the quick disconnect features provided by the SAL system. Also, the system is naturally protected subsea under the ice sheet.

SAL for high-pressure liquefied natural gas (LNG) regas

The SAL can accommodate a flexible riser (instead of a hose string assembly) and a high-pressure swivel to moor LNG carriers and floating storage regasification units or regas vessels.

 
Resources
  • APL Mooring and Loading Systems Brochure

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