Calculate the mass of salt water ballast, density 1.025 t/m3, that can be loaded into the tank. Solution Mass = Volume × Density Therefore:Ġ.389 = 0.389 = 2.701 t/m 3 (0.8 × 0.6 × 0.3) 0.144Įxample 3 A rectangular ballast tank is 12 m long, 8 m wide and has a depth of 4 m. Solution Mass = Volume × Density Mass = (0.1 × 2.2 × 6.0) × 7.80 Mass = 10.296 tonnesĮxample 2 A block of aluminium measures 0.8 m × 0.6 m × 0.3 m and has a mass of 0.389 tonnes.

Tonnes (t) cubic metres (m3) tonnes per cubic metre (t/m3)Įxample 1 A piece of steel measures 0.1 m × 2.2 m × 6.0 m and has a density of 7.80 t/m3. This can be expressed as:įor ship stability purposes the units commonly used are: mass: volume: density: Applies (2) and (3) to calculations based on the flotation of box-shaped vessels.ġ.1.1 Density The density of any given substance is its mass per unit volume. Understand the change in draught/freeboard that will occur when a box-shaped vessel moves between water of different densities. Understand the terms Density, Mass and Volume and be able to complete simple calculations relating to these terms. Learning Objectives On completion of this section the learner will achieve the following: 1. It will form the basic level of understanding necessary to complete this learning program. INTRODUCTION This section introduces the laws governing flotation and will help in the understanding of why ships float.