Pressed up <Pressed-up tanks>
Pressed up means completely full with no voids caused by trim or inadequate venting. Anything less than 100% full, for example the 98% condition regarded as full for operational purposes, is not acceptable. Preferably, the ship should be rolled from side to side to eliminate entrapped air before taking the final sounding. Special care should be taken when pressing fuel oil tanks to prevent accidental pollution. An example of a tank that would appear pressed up, but actually contains entrapped air, is shown in figure A1-2.1.3.
Source: IMO resolution MSC.267(85), International Code on Intact Stability, 2008 (2008 IS Code), 4 December 2008, International Maritime Organization. Regulatory Guidance