What is Archimedes’s principle?

What mass will the gauge now indicate?

The block is now displacing a volume of water where:

Volume of water displaced = (2 m × 2 m × 1 m) = 4 m³
Mass of water displaced = Volume × Density of the dock water;

= 4 m³ × 1.020 t/m³
= 4.08 t which represents the upthrust due to Buoyancy force (Bf) created by the displaced water.
Mass of block                   62.72 t
Upthrust due to Bf            4.08 t
Gauge reading                 58.64 t   

What mass will the gauge indicate if the crane driver now lowers the block so that it is completely submerged in the dock water?

The block is now displacing a volume of water where:
Volume of water displaced = (2 m × 2 m × 2 m) = 8 m3
Mass of water displaced =        Volume × Density of the dock water;
=      8 m3 × 1.020 t/m3
=      8.16 t which represents the upthrust of the buoyancy force (Bf) created by the displaced water.
Mass of block =                 62.72 t
Upthrust due to Bf=        8.16 t
Gauge reading=                54.56 t