Hong Kong's waters
The finds include this European-pattern cannon that researchers think may have been carried on a merchant ship as a defence against pirates, which were a frequent scourge of trading vessels in the waters around Hong Kong until the mid-1800s.
In this image, Paul Harrison, a conservator at the Hong Kong Maritime Museum, removes centuries of seabed sediments from the cannon. [Read full story about Hong Kong's maritime artifacts]
A team of seven divers from the group made a total of 25 dives to free the 1-ton gun, where it had accreted to rocks on the seabed, and raise it to the surface with an air-filled "lift bag." This image shows the recovery boat lifting the cannon, with the yellow lift bag still attached.
Protection against pirates?
Expedition leader and archaeologist Bill Jeffery says these sort of cannons were commonly fitted on European merchant vessels to give them some protection against pirates.
The crust of coral and other built-up sediments that cemented the gun to the seabed can be seen in this image.
Guns from the early 1800s bearing similar foundry marks have been found in India, Japan and New Zealand. Because most naval guns were made at well-recognized foundries, the researchers don’t think this gun came from a naval ship.
The researchers think the anchor stock comes from a merchant vessel that anchored above the site during China’s Song Dynasty, which lasted from 960 A.D. to 1279 A.D.
Soon after the Song Dynasty, changes in technology made large iron anchors more practical, and the Song-style anchors went out of use.
The archaeological dive group and the Hong Kong Maritime Museum, who are working together on the latest recovery efforts, hope the anchor stock and the cannon will be able to go on display in the museum after conservation work is completed in one or two years.