This diagram shows the challenge of raising the Nanhai One intact—a first in Chinese maritime archaeology. After sealing the wreck inside a giant steel caisson (2–4), engineers used the Hua Tian Long crane ship to lift the entire 3,800-ton structure from the seafloor (5). and move it closer to the shore (6-7) before raising it to the surface.

Image Source: Adapted from https://pic.nfapp.southcn.com/nfplus/ossfs/pic/xy/201812/18/f3cbf23c-82…