1597, more than a century and a half after Zheng He's voyages. The 3 contemporary accounts of Zheng He's voyages do not have the ship dimensions. The zhang was fixed at 141 inches in the 19th century, making the chi 14.1 inches. However the common Ming value for chi was 12.2 inches and the value fluctuated depending on region. The Ministry of Works used a chi of 12.1 inches while the Jiangsu builders used a chi of 13.3 inches. Some of the ships in the treasure fleet, but not the treasure ships, were built in Fujian, where the chi was 10.4 to 11 inches. Assuming a range of 10.5 to 12 inches for each chi, the dimensions of the treasure ships as recorded by the History of Ming would have been between 385 by 157.5 feet and 440 by 180 feet (117.5 by 48 metres, and 134 by 55 metres). Louise Levathes estimates that it had a maximum size of 110–124 m (390–408 feet) long and 49–51 m (160–166 feet) wide instead, taking 1 chi as 10.53–11.037 inches. According to British scientist, historian and sinologist Joseph Needham, the dimensions of the largest of these ships were by . American historian Edward L. Dreyer is in broad agreement with Needham's views. Modern estimates Modern scholars have argued on engineering grounds that it is highly unlikely that Zheng He's ship was in length. Guan Jincheng (1947) proposed a much more modest size of 20 zhang long by 2.4 zhang wide (204 ft by 25.5 ft or 62.2 m by 7.8 m). Xin Yuan'ou, a shipbuilding engineer and professor of the history of science at Shanghai Jiao Tong University, argues on engineering grounds that it is highly unlikely that Zheng He's treasure ships were 450 ft long, and suggests that they were probably closer to 200–250 ft (61–76 m) in length. Hsu Yun-Ts'iao does not agree with Xin Yuan'ou: Estimating the size of a 2,000 liao ship with the Treatise of the Longjiang shipyard (龙江船厂志—lóng jiāng chuánchǎng zhì) at Nanking, the size is as follows: LOA , bottom's hull length , overhanging "tail" length , front depth , front width , midhull depth , midhull width , tail depth , tail width , and the length to width ratio is 7:1. Dionisius A. Agius (2008) estimated a size of 200–250 ft (60.96 m–76.2 m) and maximum weight of 700 tons. Tang Zhiba, Xin