At discharging ports, the cargo is ‘bled’ into the cargo hold immediately beneath through openings which are sealed when all cargo has been discharged and preparation made to take on ballast water. The operation also gives rise to the term ‘bleeding wing tanks‘. Although occasionally used, the system is by no means universally employed owing to the difficulties of satisfactorily cleaning and drying out the wing tank spaces – especially in cold or humid conditions – and the increasing expense in human labour terms of the entire operation. Purists will argue that there are no true ‘self-trimming bulkcarriers’, since such a vessel would require sloping areas located fore and aft of the hatchway openings, as well as to port and starboard and that, therefore, the expression is misleading. In reality one is fully aware of the limitations of ‘self-trimming’ vessels although, to be fair, there may be legal problems when utilising this expression, with certain commodities in rare situations giving rise to serious disputes. Thus some owners prefer to use the less onerous expression ‘easy-trimmer’ when describing their vessels. In the bottoms of the cargo holds are ‘tanktops‘ covering ‘double bottom tanks‘, just as for general-cargo ships, and in some cases (see Appendix 1:3), bulkcarriers have ‘side‘ and/or ‘lower wing tanks‘. The upper sides of lower wing tanks in the cargo holds give rise to the expression ‘hoppered holds‘, although some bulkcarrier designs have virtually square-bottomed, flat hold floors, particularly specialised ‘container-bulkcarriers‘ – ‘con-bulkers‘ – designed to perform in both the bulk cargo and container market sectors, and needing this facility for the convenient and safe stowage of containers and, perhaps palletised cargo. For other bulkcarrier types – e.g. colliers – hoppered holds are desirable to assist the safe security of bulk cargo and to minimise its movement at sea.