Thailand. (Siam Steam Navigation Company - Postmarks). 1917. SG 169, 10s olive-brown and black cancelled by large double ring oval 'S.S. "Prachatipok"
The 'S.S. "Prachatipok" (968 tones) was built in 1909 for the 'Siam Steam Navigation Company.' The Company was formed as the 'Danish East Asiatic Company' in 1897. The Company had a steamer calling port to port from Bangkok down the Malay Peninsula with passengers, goods and had a contract to carry the mail. More vessels were added until the 'Siam Steam Navigation Co' was founded in 1909. The steamers would carry mail from port to port in the ships mail bag. Loose letters were cancelled by the Purser's fancy rubber hand-stamp and mail cancelled on board ship is very rare indeed.
The "S.S. Prachatipok" was used on the Bangkok - Singapore route and changed its name to "Bang Nara" after World War 11.