When measuring level by ullage method, the sounding tape is inserted only till the bob/ tape touches some part of the fluid top surface. Instead of measuring the whole depth of the tank, only the free space (from the top of sounding pipe to liquid surface) is measured (Check Figure).
How do you measure ullage?
Ullage is the void space in the tank measured from the top of the tank to the upper surface of the fluid.
How would you take a sounding of tanks by Innage and ullage?
Method to take sounding of the ballast water tank:
- Apply the water finding paste onto the sounding tape in the area of estimated depth.
- Drop the sounding tape inside the sounding pipe.
- Ensure the bob strikes the striker plate at the bottom of the tank.
- Coil up the tape looking up for the impression.
