I think Portuguese unit should be a ground unit, since in game all unique units are land units and no strength in having one more move in the carrack I think.
My suggestion is:
Portuguese Arquebusier - replaces musketman
8 1 70 +25% city protection
Description:
The figure bellow represents a Portuguese Arquebusier in the campaigns of India in the XVI century. The figure was based on the tapestries of ‘D.João de Castro’ that illustrate the siege of the Fortress of Diu in India in 1546. This soldier wears a Portuguese Combed Morion and a Corslet to protect his chest. He is equipped with Matchlock Arquebus (name derived from the dutch word Haak-Bus) and a powder flask. The arquebus was the main weapon of the Portuguese in the XVI century. This soldier is dressed in a green doublet, baggy breeches, purple stockings and cow skin shoes.
History:
The Portuguese discovered the maritime way to India in 1498 with the fleet commanded by Vasco da Gama, during the Reign of D. Manuel I. At the time the coast of Malabar and the Indic Ocean was dominated by the Arabs and Turks that controlled the trade between the west, the East and Far-East.
The arrival of the Portuguese changed the balance of forces and soon they would dominate and rule the Asian seas during the entire XVI century substituting the role of the Arabs and turks. As a result, Lisbon became the most prominent city of Europe - ´the capital of the world’ . To ensure control of the seas, the Portuguese built fortresses along the eastern African coast, Malabar coast (India) and Malaca. In 1543, the Portuguese arrived to Japan and were the first Europeans to introduce Firearms in that country. The Portuguese presence in the Asian Seas lasted four centuries until the XX century (India 1961, East Timor 1974 and Macau - China 1999).
In March 1546 , during the government of D.João de Castro, the fortress of Diu built in the coast of Cambaia in India was put under siege by Kodja Sofar with an Army of 7 000 ’Guzerates’ , 1 000 Turkish and 60 artillery guns that would later be reinforced to a total of 40 000 men. The Portuguese were defending the fortress with a strength of 3 500 men in its peak of reinforcements. The great battle of Diu that took place on November 11th, 1546 in a combined action of Land and Sea (where the Portuguese had total control) forces, resulted in a triumphal victory for the Portuguese forces. This victory was key to establish a determined presence of Portugal in India. Portugal would only leave Diu in 1961 after the Invasion of the Army of the recently formed Indian Union.