Terminal · Marine
Single Point Mooring Buoy
A large buoy anchored offshore where big tankers moor and load or unload through hoses, with no jetty needed.
What it does
The tanker ties to the buoy with a hawser and swings freely with wind and current. Oil flows from a pipeline end manifold on the seabed, up subsea hoses to the buoy's swivel and through floating hoses to the ship. Most terminals built since the mid 1990s use the catenary anchor leg type.
Basics
| Common type | CALM, catenary anchor leg mooring |
| Anchored by | Usually six or eight chains |
| Parts | PLEM, subsea hoses, swivel, floating hoses, hawser |
| Safety | Breakaway coupling on the hose string |
Common failures
- Hose leak from wear or fatigue in the floating or subsea hoses
Troubleshooting
- Symptom
- Sheen around the buoy during loading
- Likely cause
- Hose or swivel seal leak
- What to check
- Stop transfer, isolate at the PLEM and inspect the hose string