Unknown Vessels

Unknown vessels are created by the system with vessel class T (tank). Unknown vessel numbers are generated using next numbers. They are stored in the Unknown Vessel Master table (F31B103).Unknown vessels have an infinite capacity. You can define an unknown vessel for operations that are in Draft, Planned, or Active status. The preceding operation that fills the unknown vessel has to be at status Active, Actual, or Closed. If both the filling operation and the new operation are in the same work order, the status of the preceding operation can also be Draft or Planned.

After you have replaced an unknown vessel with an actual vessel in an operation, the system performs the following updates:

• The operation is removed from the dependency chain of the unknown vessel and added to the dependency chain of the actual tank.

• The system recalculates the downstream operations in both dependency chains.

The unknown vessel is not automatically replaced during this process. You can do so manually in the Create/Edit Operation Detail program (P31B87). To replace an unknown vessel with an actual vessel, you can access the Rename Vessels program (P31B67N).

Unknown vessels can be reused as long as they are not closed.