Definition(s)
Subsea buoy systems
Subsea buoy systems are used to achieve S-shaped riser configurations, including lazy (Figure 19), steep (Figure 20) and reverse configurations (note that in the reverse configuration the lower catenary of the riser passes back underneath the buoy). The objective of the subsea buoy is to provide upthrust, longitudinal fixture and guidance to the supported risers. The subsea buoy typically consists of buoyancy tanks or elements, supported by a metallic structure, over which lie individual gutters for each flexible pipe.
Source: API RP 17L2, Recommended Practice for Flexible Pipe Ancillary Equipment, First Edition, March 2013. Global Standards