For a type B ship to be assigned as a type B-60 ship, following four requirements needs to be fulfilled -

1. Adequate crew protection
2. Adequate freeing arrangements
3. Fixed steel hatch covers with adequate strength and sealing
4. Ship when fully loaded shall be able to withstand flooding of any compartment transversally and longitudinally; then

In this case the freeboard of the ship can be reduced to 60% of the freeboard difference between the Type A and Type B ship of same length and size. Hence this ship is called Type B-60 ship.