The Maritime Museum in Galle showcases a collection of boat models, maps, artillery and things found from ship-wrecks, some almost a century old. It is inside a 1671 Dutch warehouse, and was severely affected by the 2004 tsunami in Sri Lanka - but since 2010 has bounced back with aid from the Netherlands, and is pretty well maintained and informative.
You get a lot of Chinese ceramic retrieved from ships, and some interesting relics and depictions of real people. It's worth the tour if you like models of ships and are fascinated by objects preserved over centuries. Here are some photos to take you through.
The signature yellow walls of the fort Museum
Creepy realistic depictions of Sri Lanka's inhabitants in 12,000-10,000 BP
A detailed model of a ship - there were also real fishermen boats like the Madel Oruwa
Another very realistic dummy of a hand-loom worker
A Nepalese or Indonesian depiction of the Buddha, damaged by the tsunami
A painting from the 19th century telling the story of the arrival of Prince Vijaya
Lead bullets used by sailors
Entrance fee for locals is Rs. 50.