Answer:
4 cm
Step-by-step explanation:
The boat will displace an additional 140 kg of sea water
the volume of this sea water is 140 kg / 1030 kg/m^3 = .1359 m^3
the boat will sink this volume
.1359 m^3 = 3.3 m^2 * depth
depth = .0412 m = 4.12 cm = ~ 4 cm