Whereas early ports tended to be just simple harbours, modern ports tend to be multimodal distribution hubs, with transport links using sea, river, canal, road, rail and air routes. Successful ports are located to optimize access to an active hinterland, such as the London Gateway. Ideally, a port will grant easy navigation to ships, and will give shelter from wind and waves. Ports are often on estuaries, where the water may be shallow and may need regular dredging. Deep water ports such as Milford Haven are less common, but can handle larger ships with a greater draft, such as super tankers, Post-Panamax vessels and large container ships. Other businesses such as regional distribution centres, warehouses and freight-forwarders, canneries and other processing facilities find it advantageous to be located within a port or nearby. Modern ports will have specialised cargo-handling equipment, such as gantry cranes, reach stackers and forklift trucks.