The Etna class ships and nine torpedo boats were ordered by Siam in 1938.
Construction continued until December 1941 when the Italian government took over the ships and wanted to convert them into anti-aircraft cruisers that could carry cargo. On August 6, 1942, new designs were given to the shipyards and the ships were renamed.
Soldiers could be carried in a deckhouse that was located where the catapult would have gone. Four cargo holds were installed and collapsible crane derricks were used to move cargo in and out of the four cargo holds.
Each of the boilers were installed into their own space.