Abstract: A freight transport vehicle convertible for carrying piece goods as well as bulk liquid cargo, includes a collapsible liquid cargo bag and at least one adjustable cinching strap for being tightened down over the bag. Tightening of the strap over the bag causes the pressure of the liquid mass within the bag to increase, serving to make the liquid mass act as a solid mass within the bag. This prevents kinetic energy that is built up in the mass through motion of the vehicle from causing sloshing motion of the liquid during transportation, thus eliminating possible hazards in operation of the vehicle and preventing possible damage to the cargo bag.