<P> There is little attempt to provide an accurate 2 - D representation; instead the sailing instructions are given using a 24 - point compass system with a Chinese symbol for each point, together with a sailing time or distance, which takes account of the local currents and winds . Sometimes depth soundings are also provided . It also shows bays, estuaries, capes and islands, ports and mountains along the coast, important landmarks such as pagodas and temples, and shoal rocks . Of 300 named places outside China, more than 80% can be confidently located . There are also fifty observations of stellar altitude . </P> <P> Traditional and popular accounts of Zheng He's voyages have described a great fleet of gigantic ships, far larger than any other wooden ships in history . </P> <P> Chinese records state that Zheng He's fleet sailed as far as East Africa . According to medieval Chinese sources, Zheng He commanded seven expeditions . The 1405 expedition consisted of 27,800 men and a fleet of 62 treasure ships supported by approximately 190 smaller ships . The fleet included: </P> <Ul> <Li> "Chinese treasure ships" (宝船, Bǎo Chuán), used by the commander of the fleet and his deputies (nine - masted, about 127 metres (417 feet) long and 52 metres (171 feet) wide), according to later writers . </Li> <Li> Equine ships (馬 船, Mǎ Chuán), carrying horses and tribute goods and repair material for the fleet (eight - masted, about 103 m (338 ft) long and 42 m (138 ft) wide). </Li> <Li> Supply ships (粮 船, Liáng Chuán), containing staple for the crew (seven - masted, about 78 m (256 ft) long and 35 m (115 ft) wide). </Li> <Li> Troop transports (兵船, Bīng Chuán), six - masted, about 67 m (220 ft) long and 25 m (82 ft) wide . </Li> <Li> Fuchuan warships (福 船, Fú Chuán), five - masted, about 50 m (160 ft) long . </Li> <Li> Patrol boats (坐 船, Zuò Chuán), eight - oared, about 37 m (121 ft) long . </Li> <Li> Water tankers (水 船, Shuǐ Chuán), with 1 month's supply of fresh water . </Li> </Ul>

Which emperor sent out naval expeditions to explore the indian ocean