They were not made by the people around the Malacca straits, large shipbuilding industry only existed in the eastern half of Java.
[9]: 153 [10]: 172 The 3rd century book Strange Things of the South (南州異物志 — Nánzhōu Yìwùzhì) by Wan Chen (萬震) describes ships capable of carrying 600–700 people together with more than 10,000 hu (斛) of cargo (250–1000 tons according to various interpretations[5]: 275 —600 tons deadweight according to Manguin).
[note 2] The people beyond the barriers, according to the size of their ships, sometimes rig (as many as) four sails which they carry in row from bow to stern.
This oblique rig, which permits the sails to receive from one another the breath of the wind, obviates the anxiety attendant upon having high masts.
He also made reference to monsoon trade between the islands (or archipelago), which took a month and a few days in a large po.
After 5 months, the crew and the passengers embarked on another ship comparable in size to sail back to China.
The ships are constructed by assembling several thicknesses of side planks, for the boards are thin and that they fear they would break.
[25][26] Pingzhou Ketan by Zhu Yu (made between 1111 and 1117 AD) mentioned sea-going ships of Kia-ling (訶陵 — Holing or Kalingga kingdom of Java), in which the large ships could carry several hundred men, and the smaller ones over a hundred men.
[27]: 30–31 Wang Dayuan's 1349 composition Daoyi Zhilüe Guangzheng Xia ("Description of the Barbarian of the Isles") described the so-called "horse boats" at a place called Gan-mai-li in Southeast Asia.
Wang made special mention of these ships because pepper, which is also transported by them, carried to faraway places with large quantity.
[28]: 33 [29]: 170 [12] Indian historians usually call this ship colandia (Tamil: சொழாந்தியம்), which they attribute to the Early Chola navy.
The second variety, called kolandiaphonta, was very large in size and these types of vessels were used for voyages to the Ganges and the Chryse, which was the name of various places occurring in ancient Greek geography.
[32][33] It is now generally accepted that kolandiaphonta was a transcription of the Chinese term Kun-lun po, which refers to an Indonesian vessel.