In the 1990s, advancements in surfboard design centered on the rail curve and what could be done with the board's underside. For different surfing ability, multiple rail bends are offered. A straight-cut rail enables for quicker turns, but a softer, curved rail slows turns and is excellent for novices. Surfboards are now designed with various types of rails and shapes that suit different types of waves and surfers. Other designs include those with concave or convex sides, which give the board its shape; directional surfboards, which tilt one side slightly forward when riding down the face of a wave to provide more speed; and longboards, which are wider than normal surfboards and have larger volume tires mounted on them for cruising on flat surfaces. Longboards are used for surfing local beaches as well as for exploring large bodies of water such as lakes or the ocean. Long before any other form of transportation was invented, people were using surfboards to travel across oceans. In fact, the first documented case of a surfboard being used for transportation happened in 1619, when English merchant William Weston traveled from Peru to Mexico on a wooden surfboard made by hand. Although this example isn't very efficient, it shows that surfboards can be used for traveling over large distances. Since then, many others have been developed for traveling across oceans. Some people build their own boats with which they sail to remote places where there are no ports available.