In Singapore, commercial sailing vessels transported goods until the mid 1980s. The last of these were the timber tongkangs, which were unique to Singapore.
These were large wooden boats, about 90 feet from stem to stern, and 30 feet wide, with a depth amidships of 12-15 feet. They carried a long bowsprit forward, which had a characteristic lattice appearance when viewed from above, and were steered with a tiller attached to a large, stern-hung perforated rudder. Timber tongkangs were built for the purpose of carrying logs of timber, although later on they also carried firewood and charcoal, and traded between Singapore, southern Johor and Sumatra. They were designed, built and sailed by Chinese, but had a western gaff ketch rig , with a boomed mizzen, a loose footed main, staysail, and jibs. Accommodation for the crew of 6 to 7 men was in a raised area at the stern.
The timber tongkang was slow and unwieldy. However, used to transport non-perishable goods, it was economical to operate and could be used in areas with rudimentary port facilities, which explains why it persisted as long as it did.
I've been doing some research into these vessels which were a characteristic feature of the Kallang Basin in Singapore (now part of the Marina Bay), and I'll be writing more about them.