The size of the armada varied, from enormous fleets of twenty-something ships, to small fleets of only four or five. This changed over time. In the first decade (1500–1510), when the Portuguese were establishing themselves in India, the armadas averaged around 15 ships per year. This declined to around 9–10 ships in 1510–1525. From 1526 to the 1540s, the armadas declined further to 7–8 ships per year, with a few exceptional cases of large armadas (e.g. 1533, 1537, 1547) brought about by military exigency, but also several years of exceptionally small fleets. In the second half of the 16th century, the Portuguese India armada stabilized at 5–6 ships annually, with very few exceptions (rose above seven only in 1551 e 1590 and below 4 only in 1594 and 1597).

Organization was principally in the hands of the Casa da Índia, the royal trading house established around 1500 by King Manuel I of Portugal. The Casa was in charge of monitoring the crown monopoly on India trade – receiving goods, collecting duties, assembling, maintaining and scheduling the fleets, contracting private merchants, correspondence with the feitorias (overseas factories), drafting documents and handling legal matters.

Separately from the Casa, but working in coordination with it, was the Armazém das Índias, the royal agency in charge of nautical outfitting, that oversaw the Lisbon docks and naval arsenal. The Armazém was responsible for the training of pilots and sailors, ship construction and repair, and the procurement and provision of naval equipment – sails, ropes, guns, instruments and, most importantly, maps. The piloto-mor (‘chief pilot’) of the Armazém, in charge of pilot-training, was, up until 1548, also the keeper of the Padrão Real, the secret royal master map, incorporating all the cartographic details reported by Portuguese captains and explorers, and upon which all official nautical charts were based. The screening and hiring of crews was the function of theprovedor of the Armazém.

From at least 1511 (perhaps earlier), the offices of the Casa da India were based in the ground floor of the royal Ribeira Palace, by the Terreiro do Paço in Lisbon, with the Armazém nearby. (Neither the Casa nor the Armazem should be confused with the Estado da Índia, the Portuguese colonial government in India, which was separate and reported directly to the monarch.)

Ships could be and sometimes were owned and outfitted by private merchants, and these were incorporated into the India armada. However, the expenses of outfitting a ship were immense, and few native Portuguese merchants had the wherewithal to finance one, despite eager government encouragement. In the early India runs, there are several ships organized by private consortiums, often with foreign capital provided by wealthy Italian and German trading houses. This fluctuated over time, as the royal duties, costs of outfitting and rate of attrition and risk of loss on India runs were sometimes too high for private houses to bear. Private Portuguese merchants did, however, routinely contract for cargo, carried aboard crown ships for freight charges.

Marine insurance was still underdeveloped, although the Portuguese had helped pioneer its development and its practice seemed already customary.

Ships

The ships of an India armada were typically carracks (naus), with sizes that grew over time. The first carracks were modest ships, rarely exceeding 100-tonnes, carrying only up to 40–60 men, e.g. the São Gabriel of Gama’s 1497 fleet, one of the largest of the time, was only 120t. But this was quickly increased as the India run got underway. In the 1500 Cabral armada, the largest carracks, Cabral’s flagship and the El-Rei, are reported to have been somewhere between 240t and 300t. The Flor de la Mar, built in 1502, was a 400t nau, while at least one of the naus of the Albuquerque armada of 1503 is reported to have been as large as 600t. The rapid doubling and tripling of the size of Portuguese carracks in a few years reflected the needs of the India runs. The rate of increase tapered off thereafter. For much of the remainder of the 16th century, the average carrack on the India run was probably around 400t.

In the 1550s, during the reign of John III, a few 900t behemoths were built for India runs, in the hope that larger ships would provide economies of scale. The experiment turned out poorly. Not only was the cost of outfitting such a large ship disproportionately high, they proved unmaneouverable and unseaworthy, particularly in the treacherous waters of the Mozambique Channel. Three of the new behemoths were quickly lost on the southern African coast – the São João (900t, built 1550, wrecked 1552), the São Bento (900t, built 1551, wrecked 1554) and the largest of them all, the Nossa Senhora da Graça (1,000t, built 1556, wrecked 1559).

These kind of losses prompted King Sebastian to issue an ordinance in 1570 setting the upper limit to the size of India naus at 450t.^[16]Nonetheless, after the Iberian Union of 1580, this regulation would be ignored and shipbuilders, probably urged on by merchants hoping to turn around more cargo on every trip, pushed for larger ships. The size of India naus accelerated again, averaging 600t in the 1580–1600 period, with several spectacularly large naus of 1500t or greater making their appearance in the 1590s.

If the lesson was not quite learned then, it was certainly learned in August, 1592, when English privateer Sir John Burroughs (alt. Burrows, Burgh) captured the Madre de Deus in the waters around the Azores islands. The Madre de Deus, built in 1589, was a 1600t carrack, with seven decks and a crew of around 600. It was the largest Portuguese ship to go on an India run. The great carrack, under the command of Fernão de Mendonça Furtado, was returning from Cochin with a full cargo when it was captured by Burrough. The value of the treasure and cargo taken on this single ship is estimated to have been equivalent to half the entire treasury of the English crown. The loss of so much cargo in one swoop confirmed, once again, the folly of building such gigantic ships. The carracks built for the India run returned to their smaller ideal size after the turn of the century.

In the early Carreira da India, the carracks were usually accompanied by smaller caravels (caravelas), averaging 50t–70t (rarely reaching 100t), and capable of holding 20–30 men at most. Whether lateen-rigged (latina) or square-rigged (redonda), these shallow-drafted, nimble vessels had a myriad of uses. Caravels served as forward lamp, scouts and fighting ships of the convoy. Caravels on the India run were often destined to remain overseas for coastal patrol duty, rather than return with the main fleet.

In the course of the 16th century, caravels were gradually phased out in favor of a new escort/fighting ship, the galleon (galeão), which could range anywhere between 100t and 1000t. Based on the design of the carrack, but slenderer and lower, with forecastle diminished or removed to make way for its famous ‘beak’, the galleon became the principal fighting ship of the India fleet. It was not as nimble as the caravel, but could be mounted with much more cannon, thus packing a bigger punch. With the introduction of the galleon, carracks became almost exclusively cargo ships (which is why they were pushed to such large sizes), leaving any fighting to be done to the galleons. One of the largest and most famous of Portuguese galleons was the São João Baptista (nicknamed Botafogo, ‘spitfire’), a 1,000-ton galleon built in 1534, said to have carried 366 guns.

Many fleets also brought small supply ships on outward voyage. These were destined to be scuttled along the way once the supplies were consumed. The crews were redistributed and the abandoned ships usually burned to recover their iron nails and fittings.

Average speed of an India Armada was around 2.5 knots, but some ships could achieve speeds of between 8 and 10 for some stretches.