A miniature model of the HTMS Madchanu, one of the only 4 submarines that were ever used by the Royal Thai Navy, the other ones being HTMS Wirun, HTMS Sin Samut, and HTMS Phlaay Chumphon.

This type of Japanese-built submarines, of which a total of four were used by the Royal Thai Navy between 19 July 1938 and 30 November 1951, were 51 meters long, 4.1 meters wide, and equipped with four 450 millimeter torpedo tubes (fig.). After being decommissioned, the sail or fin of the HTMS Madchanu (fig.), was put on display at the Chulachomklao Fortress (fig.) and Naval Base in Samut Prakan.