Small, manoeuvrable, shallow draft ships are often referred to as "coasters". They can be specialised to either carry wet or dry bulk, containers, or they could be described as "general". These types of ships are normally found plying coastal areas with cargoes of oil products, building aggregates, scrap metal, china clay, containers and general supplies for island communities. More modern coasters are usually of the low draught - low air-draught design. That is they not only have a shallow draught in the water, but also, normally by means of a hyraulic bridge lowering and lifting mechanism, they can reduce their height in the air. This gives them the caperbility of not oly operting in small ports and harbours, but also to penetrate inland waterways, navigating under bridges etc. Small coasting vessels by using the Maas/Rhine river can penetrate far into Germany. Depending upon the ship it is also quite possible to circumnavigate Europe!