Tuyến thương mại
Mỗi mùa xuân, các hạm đội hoàng gia Bồ Đào Nha rời Lisboa, vòng xa ra Nam Đại Tây Dương để đón gió tây đưa tới mũi Hảo Vọng, rồi theo gió mùa hạ từ Đông Phi tới Goa và Cochin. Họ trở về với hồ tiêu và các loại gia vị khác đầy khoang, và trong khoảng một thế kỷ không cường quốc châu Âu nào khác đi tuyến đường này.
The Portuguese Indian Armadas were the fleets of ships funded by the Crown of Portugal, and dispatched on an annual basis from Portugal to India. The principal destination was Goa, and previously Cochin. These armadas undertook the Carreira da Índia ('India Run') from Portugal, following the maritime discovery of the Cape Route, to the Indian subcontinent by Vasco da Gama in 1497–99.
The annual Portuguese India armada was the main carrier of the spice trade between Europe and Asia during the 16th Century. The Portuguese monopoly on the Cape route was maintained for a century, until it was breached by Dutch and English competition in the early 1600s. The Portuguese India armadas declined in importance thereafter. During the Dutch occupation of Cochin and the Dutch siege of Goa, the harbour of Bom Bahia, now known as Mumbai (Bombay), off the coast of the northern Konkan region, served as the standard diversion for the armadas.
For a long time after its discovery by Vasco da Gama, the sea route to India via the Cape of Good Hope was dominated by the Portuguese India armada – the annual fleet dispatched from Portugal to India, and after 1505, the Estado da India. Between 1497 and 1650, there were 1033 departures of ships at Lisbon for the Carreira da Índia ("India Run").
The India armada typically left Lisbon and each leg of the voyage took approximately six months. The critical determinant of the timing was the monsoon winds of the Indian Ocean. The monsoon was a southwesterly wind (i.e. blew from East Africa to India) in the summer (between May and September) and then abruptly reversed itself and became a northeasterly (from India to Africa) in the winter (between October and April). The ideal timing was to pass the Cape of Good Hope around June–July and get to the East African middle coast by August, just in time to catch the summer monsoon winds to India, arriving around early September. The return trip from India would typically begin in January, taking the winter monsoon back to Lisbon along a similar route, arriving by the summer (June–August). Overall, the round trip took a little over a year, minimizing the time at sea.
The critical step was ensuring the armada reached East Africa on time. Ships that failed to reach the equatorial latitude on the East African coast by late August would be stuck in Africa and have to wait until next spring to undertake an Indian Ocean crossing, and would then have to wait in India until the winter to begin their return, so any delay in East Africa during those critical few weeks of August could end up adding an entire extra year to a ship's journey.
The circumnavigation of Madagascar opened an alternative route to get to India, which gave more flexibility in timing. The rule that quickly emerged was that if an outbound armada doubled the Cape of Good Hope before mid-July, then it should follow the old "inner route" – that is, sail into the Mozambique Channel, up the East African coast until the equatorial latitude (around Malindi, in modern-day Kenya), then take the southwesterly monsoon across the ocean to India. If, however, the armada doubled the Cape after mid-July, then it was obliged to sail the "outer route" – that is, strike out straight east from South Africa, go under the southern tip of Madagascar, and then turn up from there, taking a northerly path through the Mascarenes islands, across the open ocean to India. While the outer route did not have the support of African staging posts and important watering stops, it sidestepped sailing directly against the post-summer monsoon.
Return fleets were a different story. The principal worry of the return fleets was the fast dangerous waters of the inner Mozambican channel, which was particularly precarious for heavily loaded and less maneuverable ships. In the initial decades, the return fleet usually set out from Cochin in December, although that was eventually pushed forward to January. January 20 was the critical date, after which all return fleets were obliged to follow the outer route (east of Madagascar) which was deemed calmer and safer for their precious cargo. That meant they missed the important watering stop on Mozambique island on the return leg and had to put in elsewhere later, such as Mossel Bay or St. Helena. Between 1525 and 1579, all return fleets were ordered to follow the outer route. This rule was temporarily suspended between the 1570s and 1590s. From 1615, a new rule was introduced whereby return fleets from Goa were allowed to use the inner route, but return fleets from Cochin still had to use the outer route. With the entry of Dutch and English competition in the 1590s, the start of the return legs were delayed until February and March, with the predictable upsurge in lost and weather-delayed ships.
Arrival times in Portugal varied, usually between mid-June and late August. It was customary for return fleets to send their fastest ship ahead to announce the results in Lisbon, before the rest of the fleet arrived later that summer.
Because of the timing, an armada had to leave Lisbon (February–April) before the previous year's armada returned (June–August). To get news of the latest developments in India, the outgoing armada relied on notes and reports left along the way at various African staging posts by the returning fleet.
Portuguese India armadas tended to follow the same outward route. There were several staging posts along the route of the India Run that were repeatedly used.
Setting out from Lisbon (February–April), India-bound naus took the Canary Current straight southwest to the Canary Islands. The islands were owned by Castile and so this was not a usual watering stop for the Portuguese India armadas, except in emergencies.
The first real obstacle on the route was the Cape Verde peninsula (Cap-Vert, Senegal), around which the Canary Current ends and the equatorial drift begins. Although not difficult to double, it was a concentration point of sudden storms and Cape Verde-type hurricanes, so ships were frequently damaged.
The Cape Verde islands, to the west of the Cape Verde peninsula, were the usual first stop for India-bound ships. Relative scarcity of water and supplies on the islands made this a sub-optimal stop, but the islands (especially Santiago) served as a harbor against storms and were frequently a pre-arranged point for the collection and repair of damaged ships.
The Angra de Bezeguiche (Bay of Dakar, Senegal) was a common watering stop for ships after doubling Cape Verde. The shores were controlled by Wolof and Serer kingdoms, whose relations with the Portuguese were ambivalent, so a warm reception on the mainland could not always be counted on. In the middle of the bay was the island of Gorée (ilha de Bezeguiche), a safe anchoring spot, but the island itself lacked drinkable water. As a result, ships frequently watered and repaired at certain mainland points along the Petite Côte of Senegal such as Rio Fresco (now Rufisque) and Porto de Ale (now Saly-Portudal). It was not unheard of for India naus to water much further south, among the many inlets and islands (e.g. Bissagos) along the African coast to Sierra Leone.
Below Cape Verde, around the latitudes of Sierra Leone, began the Atlantic doldrums, a calm low pressure region on either side of the equator with little or no winds. At this time of year, the doldrums belt usually ranged between 5° N and 5° S. In the southern hemisphere, below the doldrums, the counter-clockwise gyre of the South Atlantic and the southeasterly trade winds, prevented sailing directly southeast to the Cape.
Passing the doldrums was a navigational challenge, and pilots had to avail themselves deftly of the currents and every little breeze they could get to stay on course. The usual tactic was to proceed south or even southeast along the West African coast as long as possible, until the doldrums hit (usually around Sierra Leone), then to strike southwest sharply, drift over the doldrums and then catch the South Equatorial Current (the top arm of the South Atlantic gyre) towards the coast of Brazil. This was usually referred to as following the volta do mar (literally, 'turn of the sea', i.e. the South Atlantic gyre).
The volta do mar was usually contrasted to the rota da Mina (Mina route). The latter meant striking southeast in the doldrums to catch the Equatorial Counter Current (or Guinea Current) east into the Gulf of Guinea. This was the usual route to the fort of São Jorge da Mina on the Portuguese Gold Coast. This was not part of the India run. The route from Mina down to South Africa involved tacking against the southeasterly trade winds and the contrary Benguela Current, a particularly tiresome task for heavy square rigged carracks. However, it sometimes happened that by poor piloting, India naus would be inadvertently caught by the Guinea counter-current and forced to take that route, but such ships would not be likely to reach India that year.
Assuming the India armada successfully caught the south equatorial current of the volta do mar, the armada would drift southwest through the doldrums and reach the southbound Brazil Current off the coast of Brazil (around Pernambuco). Although India naus did not usually stop in Brazil, it was not unheard of to put in a brief watering stop at Cape Santo Agostinho (Pernambuco, Brazil), especially if the southeasterly trade winds were particularly strong (pilots had to be careful not to allow themselves to be caught and driven backwards).
From the environs of Pernambuco, the India naus sailed straight south along the Brazil Current, until about the latitude of the Tropic of Capricorn, visibly the Abrolhos islands or the Trindade and Martim Vaz islands, where they began to catch more favorable prevailing westerlies. These would take them quickly straight east, across the South Atlantic, to South Africa.
The Cape of Good Hope–once aptly named the "cape of storms"–was a very challenging headland on the India Run. The outbound crossing was always difficult, and many a ship was lost here. Larger armadas often broke up into smaller squadrons to attempt the crossing, and would re-collect only on the other side – indeed quite far on the other side. There was usually no stop or collection point after the Cape crossing until well inside the Mozambique Channel. The reason for this is that outbound ships tried to steer clear from the South African coast, to avoid the rushing waters of the contrary Agulhas Current.
The exception was the Agoada de São Brás (Mossel Bay, South Africa), a watering stop after the Cape. It was not always used on the outbound journey since individual ships often charted wide routes around the Cape, and sighted coast again only well after this point. However, ships damaged during the crossing frequently had no choice but to put in there for emergency repairs. Trade for food supplies with the pastoral Khoikhoi peoples that lived in the area was frequent (although there were also occasional skirmishes). São Brás was a more frequent stop on the return journey, as a place to repair the ships before doubling the Cape the other way. As a result, particularly in early years, São Brás was used as a postal station, where messages from the returning armadas would be left for the outward armadas, reporting on the latest conditions in India.
If the armada went by the inner route, then the next daunting obstacle was Cape Correntes, at the entrance of the Mozambique Channel. Treacherously fast waters, light winds alternating with unpredictably violent gusts, and dangerous shoals and rocks made this cape particularly dangerous. It is estimated that of all the ships lost on the India Run, nearly 30% of them capsized or ran aground around here - more than any other place.
The ideal passage through the Mozambique Channel would be to sail straight north through the middle of the channel, where a steady favorable wind could be relied upon at this season, but this was a particularly hard task in an era where longitude was determined largely by dead reckoning. If a pilot miscalculated and charted a course too close to the African coast, the current ran south, the winds were light or non-existent, subject to arbitrary gusts from strange directions, and the coasts were littered with shoals. Into this dreaded mix, Cape Correntes added its own special terror to the experience. The Cape was not only a confluence point of opposing winds, which created unpredictable whirlwinds, it also produced a strange and extraordinarily fast southerly current, violent enough to break a badly-sewn ship, and confusing enough to throw all reckoning out the window and lure pilots into errors.
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