Djong Ship: Springald ship shared with the Mayapit Empire that is more resistant and shoots a little bit faster.
I don’t think Djong/Jong is fit for Chola civ. Djong characteristics are noticeably Austronesian (the use of double quarter rudders and the use of tanja sail). Indian ships are using square sails or tall but narrow square sails. Also, no record of jong existed about its usage by Indian polities.
It is more suited as the unique ship for Javanese civ. Or probably shared for Nusantaran (i.e. Maritime Southeast Asian) civs. They are recorded first in a Balinese inscription written in Old Javanese (1065 AD or 11th century), and then recorded as being used by the Sundanese in 1357 AD. The Malays recorded jong quite late, in the 15th century AD, being recorded in Hikayat Raja-Raja Pasai (composed between 1428 and 1448).
They may have been known as far as the Philippines, as the Juanga may have its etymological roots from jong. Burmese civ, if available, may also use jong, as Pegu/Bago produced it too.
Djong would be a counterpart to the Chinese baochuan, as they’re about the same size (the largest djong is bigger and heavier than the largest baochuan), and they would be a cannon ship/heavy ship, as the Javanese recorded them using bedil (cannon or any gunpowder weapon). The Portuguese who encountered them in the 16th century also recorded cannons being used.