Corrosive

Some multi-purpose vessels, however, have what are referred to as ‘twin-hatches’ – i.e. hatchways located side by side rather than fore and aft as in the case of the Freedom Mk I. The object of twin-hatches is to provide easy access to the sides of a vessel’s holds and tweendeck spaces to facilitate the handling of heavy and bulky articles – such as containers or, perhaps, railway wagons. The main disadvantage of twin-hatchways, however, is the need for a supportive centre-line beam running longitudinally between the two hatchway openings, (and sometimes an entire centre-line bulkhead), hampering bulk cargo handling. In most cases ‘tweendeck-hatchways’ are located more or less exactly beneath weatherdeck hatchways, thereby facilitating cargo handling. They usually also have the same dimensions. However, this may not be the case, especially with older vessels, and it is good practice to check this aspect when chartering tweendeckers. Within the very near future there will be some significant changes to bulkcarrier construction brought about by an increasingly poor safety record for they type generally. These changes are being pursued by the IMO (the United Nations body responsible for maritime affairs and IACS the International Association of Classification Societies). Almost all existing large bulkcarriers have a single hull, meaning that between the cargo and the ocean there are just millimetres of steel. Older bulkcarriers tend to suffer from a lack of maintenance which coupled with the corrosive effect of some cargoes has caused loss of side plates in some cases and total loss of the ship in far too many others. It is almost certain that within a few years all new bulkcarriers will be required to be built with double hulls just as all new tankers are. There will be some benefits from this change, not least a faster discharge because cargo will not “stick” between the frames of the ship’s sides and a consequent reduction in mechanical damage caused by the practice of dislodging stuck cargo using cargo grabs as hammers and swinging them at the hull.