Visit a shipyard
The only place in Southern China where a substantial number of traditional fishing sailing junks are still being used in the original way, is the relatively undeveloped Hainan island, between the Gulf of Tongkin and the Southern Chinese Sea. There seems to be a small shipyard for junks here. Exact geographical location.
In Vietnam it is much more easier to find shipyards for the local lug-rigged vessels. This is because until recently economic development of Vietnam was limited due to sanctions, there are still a great number of traditional junks and even Bengali sampams used the traditional way. They use tradition designs and materials such as bamboo. You can find them in the villages along the shores of the places mention under ,hitch a ride´.