A “new generation” of bulkers

Dry bulk carriers are tough, no-nonsense ships operating in a rough and competitive world, moving mountains of coal, iron ore, grain and other bulk shipments around the world with a minimum of fuss. They have to be exceptionally robust – with some iron ports capable of hurling 16,000 tonnes per hour into a ship, with the cargo grabbed out in the discharge terminals with massive steel grabs weighing fifty tonnes empty, the punishment upon a ship’s structure can be severe. A better understanding of both the static and dynamic stresses upon these hard-worked ships has been gained in recent years and is being reflected in modern designs.
The new generation of bulk carriers is composed of sophisticated and efficient ships, designed for more economical operations and far more environmentally sustainable than earlier vessels. Scale economies, with most classes of bulk carrier able to carry more cargo, also help to make these ships a more attractive proposition for the operator. “Greener” propulsion machinery, with substantial reductions in harmful emissions is also being offered by a number of shipbuilders specialising in bulker construction.
Early bulk carriers were basically a huge rectangular box, subdivided into holds with a ship-shaped bow and stern. The latest vessels are optimally shaped to reduce resistance, while a great deal of work has gone into enhancing the flow of water over the propeller, both by refining the shape of the stern and with a range of fins and ducts that help to make the propeller far more efficient. It has also been possible to optimise the design of the rudder and tailor it to the hull, so that energy is not wasted in keeping the ship on course.
As with other types of ship, bulkers today tend to employ a range of modern coatings to help to reduce resistance and the growth of fouling. Bulkers often find that they are at anchor waiting for a cargo berth for extensive periods and fouling can build up quickly, so special coatings that can keep growth at bay have been developed.
But in the bulker’s holds, where abrasion damage can come from grabs and from ore or coal being “shot” into the ship by powerful loaders, special coatings have been developed that will withstand such damage and ultimately prevent internal corrosion to the structure. Other “unseen” improvements come from the ability of modern ships to handle their ballast in a more efficient fashion, with far more pumping capacity and arrangements to exchange ballast at sea in a far safer manner than merely overflowing the tanks, a system required to prevent the transmission of alien species in ballast water.