Grabs are often used for unloading bulk carriers that deliver iron ore cargoes. The grabbing process starts with cutting the free surface of the bulk iron ore. For that reason, the initial penetration depth of the grabs' knives into the material is an important success factor in their filling ratio. The resistance to penetration is influenced by the consolidation process of the cargo which occurs during ship loading and sailing. In this study, a test method is developed to mimic the penetration process of the grabs' knives into material, and to determine the relationship between the level of consolidation stress and the penetration resistance. The test results show that when the consolidation stress increases, the penetration resistance, and the bulk density also increase. The results obtained from these measurements will be used in further research for improving the design of iron ore grabs.@en