FSO Nan Hai Sheng Kai Internal Disconnectable Turret
Scope of Work
SOFEC designed and constructed an internal disconnectable turret mooring system to moor a MODEC-converted 121,361 dwt FSO vessel in the typhoon alley area offshore People’s Republic of China.
The internal disconnectable turret mooring system was chosen so the FSO can disconnect and sail to safe harbour as typhoons approach. The FSO could then return to the field and reconnect after
the typhoon has passed.
This SOFEC disconnectable internal turret mooring system is ABS classed.
General Description
| Client Name: | JHN Oil Operating Company |
| Contract Award: | February 1992 |
| Installation Date: | August 1993 |
| Vessel Size: | 121,361 dwt |
| Storage Capacity: | 880,000 bbls |
| Water Depth: | 141m (463ft) |
| Fabrication: | Turret - Japan Vessel Conversion -Singapore Topsides - Singapore |
Design Environmental Criteria
Connected 5-year Non-typhoon
| Significant Wave Height: | 8m (26ft) |
| Wind Velocity: | 25m/s (48.6 knots) |
| Current: | 1.2m/s (2.3 knots) |
Disconnected 100-year Typhoon
| Significant Wave Height: | 14.4m (47.2ft) |
| Current: | 2.4m/s (4.7 knots) |
Mooring System
Turrets
8-leg Wire chain symmetrical catenary:
3.75-in., 4-in., and 5-in. ORQ chain with excursion limiter
4-in. 6-Strand wire rope
Internal Disconnectable
Fluid Swivel Assembly
| Crude Oil: | 1 x 6in piggable in-line (1,480 psi operating/ 2,225 psi test) |
| Electrical Swivel: | 440 volts at 450 amps (3 phase power) 220 volts at 30 amps (3 phase power) 100 volts at 1 ampere (10 data circuits) |
Riser System
1 x 6-in. Flexible riser