ORI GIN AL PA PER

Analysis of the Gulf of Mexico’s Veracruz-Havana Routeof La Flota de la Nueva Espana

A. Lugo-Fernandez Æ D. A. Ball Æ M. Gravois Æ C. Horrell Æ J. B. Irion

� Springer Science+Business Media, LLC 2007

Abstract During colonial times, an active maritime trade existed between Spain and the

New World, with convoys sailing annually to and from Mexico and returning via Havana,

Cuba, after wintering in America. A database constructed from secondary and open sources

revealed that Spanish vessels were sailing over open waters along a northern path near

Louisiana and a southern path across the central Gulf of Mexico. These routes were

traversed in about one month and scheduling for the convoy was based on an under-

standing of the Americas’ meteorological and oceanographic climate. However, other

factors may also have been involved in the directional layout of the routes. Today these

ancient routes crisscross planning areas for oil and gas lease sales in the US Exclusive

Economic Zone and the information presented in this article may aid in identifying areas

where historic shipwrecks may lie. Maps and documents found during this study helped

piece together the evolution of our understanding of the Gulf of Mexico surface circulation

and how this knowledge influenced sailing during colonial times.

Keywords Routes � Derrotas � Gulf of Mexico � Veracruz � Havana �New Spain � Shipwrecks

A. Lugo-Fernandez (&)Physical Sciences Unit (MS 5433), 1201 Elmwood Parkway Blvd., New Orleans, LA 70123-2394,USAe-mail: alexis.lugo.fernandez@mms.gov

D. A. Ball � C. Horrell � J. B. IrionSocial Sciences Unit (MS 5411), 1201 Elmwood Parkway Blvd., New Orleans, LA 70123-2394, USA

M. GravoisMapping and Automation Unit (MS 5413), 1201 Elmwood Parkway Blvd., New Orleans, LA70123-2394, USA

123

J Mari ArchDOI 10.1007/s11457-007-9015-5

Introduction

On August 21, 1766, a Spanish convoy left Veracruz, Mexico, for Havana, Cuba, through

the Gulf of Mexico. This voyage was to be the first leg of a return trip to Spain of one of

the convoys of La Flota de la Nueva Espana. Between September 1 and 10, a powerful

storm caught the convoy at latitude 268 N and inflicted heavy losses of two vessels along

the coasts of present day Louisiana and Texas. Since Veracruz, the embarkation port of this

convoy, lies just south of latitude 208 N and Havana, the convoy’s destination, is located

just south of latitude 23.58 N, the authors wondered why a Spanish convoy was so far north

and whether this was common or not. A cursory examination of available information

suggested that wind and current patterns were instrumental in the design of the routes that

this and other convoys followed. However, as more information was uncovered, additional

questions arose and a complete pattern of the routes emerged.

Soon after the discovery of the New World and the realization of its economic potential,

Spain began to exploit these lands, documenting this immense undertaking in great detail.

Historic documents, especially ship logs, have been used to study many aspects of this

period, including past climatic conditions, e.g., Garcıa-Herrera et al. (2004, 2005) and

Garcıa et al. (2000, 2001). Because the authors did not have access to primary sources for

this study, they examined historical maps, books, and published materials to ascertain

Spanish shipping routes from Veracruz to Havana. Ships also travelled from Havana to

Veracruz by crossing the Yucatan Channel and sailing across the southern Gulf of Mexico,

but this route differs from the one examined here. The main objectives of this study are to

analyze and ascertain the Spanish sailing routes and to identify deepwater areas (depths

>350 m) crossed by these routes in the northern Gulf of Mexico. These routes cover areas

where present-day exploration for oil and gas occurs. The inference here is that areas

crossed by Spanish sailing routes are also areas where ship losses may have occurred

during the colonial period. By exploring these routes, it may also be possible to determine

the likelihood of archaeological sites occurring in these areas as well as prevent distur-

bance of these sites from oil and gas activities on the US Outer Continental Shelf (OCS).

As a Federal regulatory agency, the Minerals Management Service (MMS) is required by

the National Historic Preservation Act of 1966 (16 USC 470) and Executive Order 11593

to consider the effects of its actions on significant cultural resources of the United States. A

secondary objective was to examine historic reports of winds and surface currents that

affected sailing to explore any differences from present conditions that could have existed.

This latter objective addresses the fact that the study period (1575–1800’s) coincides with

the Little Ice Age (LIA), a widespread climatic event starting some time between 1200 and

1400’s and ending in the late 1800’s (Grove 2001; Soon et al. 2003).

Historical development of the Armadas de la Guardia de la Carrera de las Indias

The discovery of the New World in 1492 saw a wide array of administrative and economic

strategies that, above all else, focused on maximizing trade between these newly discov-

ered lands and the Kingdom of Spain. Continued discoveries in the latter part of the

fifteenth and early part of the sixteenth centuries fuelled further conquest of the circum-

Caribbean region, resulting in the continued growth of the empire and its wealth. In 1503,

as a means to address the ever-expanding trade between Spain and its new possessions, the

Crown formed the Casa de Contratacion, a maritime council located in Seville that li-

censed and administered all colonial trade, shipping, navigation, and ran a postal service

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(Peterson 1975:58). The ordinances that gave life to the Casa de Contratacion were clear

in how trade was to be conducted. Essentially, the Casa de Contratacion chose captains

and assigned an escribano (clerk) to record all items brought aboard ships involved in trade

with the New World (Peterson 1975:57).

However, by 1510, the magnitude of trade between Spain and the New World, along

with the expanding geographical extent of the empire, overwhelmed the Spanish Crown

(Peterson 1975:57). To relieve this growing pressure, the Crown turned to private indi-

viduals and enterprises to help manage the trade. New ordinances redefined the Casa deContratacion’s function and mandated that only trade between Spain and her colonial

holdings be allowed. By 1511, the Casa de Contratacion was transformed into an official

office of the Spanish government charged with regulating the trade handled by private

individuals and companies (Peterson 1975:57).

While the Casa de Contratacion was primarily concerned with regulating trade and

preventing smuggling, this government entity focused equally on the protection of that

trade from privateers, pirates, corsairs, and other foreign interlopers. Once significant

amounts of gold and silver started to flow into Spanish coffers, European corsairs began to

lie off the coast of Spain to line their pockets with the spoils of prizes taken at sea (Smith

1988:85). Enemies of the Spanish crown also began to cruise throughout the islands of the

Caribbean with the same intent. Armed caravels and naos had already been making the run

across the Atlantic during the early part of the sixteenth century, protecting small fleets of

merchantmen carrying goods from the New World (Smith 1988:75). Even with these

protections in place, merchants in Seville were no less stunned when, in 1521, the French

captured two vessels laden with precious commodities and treasures from the New World

(Peterson 1975:60). This incident prompted the Crown to outfit a small fleet whose charge

was to patrol the waters off Cape St. Vincent, Portugal. To maintain this fleet, the Crown

initiated a tax on all trade with the West Indies. This tax, or averia, became the primary

means of maintaining ships, weapons, equipment, and men for the trade between the New

World and Spain (Peterson 1975:60).

The gradual development of the treasure fleet was predicated on the need for the Casade Contratacion to maintain control on trade and to provide protection to the fleet as it

plied the waters of the Atlantic, Caribbean, and the Gulf of Mexico. During the reign of

Charles V (1516–1556), the treasure fleet system started to take shape (Peterson 1975). The

increasing dangers associated with sailing throughout the West Indies forced government

officials to order armed escorts to accompany these vessels on each end of the trans-

Atlantic route. Merchantmen, as per a requirement of the Casa de Contratacion, were

already required to sail together as a group. The addition of armed vessels traveling with

the merchantmen during times of war would soon become a permanent feature of the

treasure fleets (Peterson 1975:61).

In 1543, government officials published regulations requiring that vessels of 100 tons or

more were to sail in groups of no less than ten and mandated that these vessels sail during

certain times of the year providing, for the first time, a regular schedule for the shipment of

commodities to and from the New World (Peterson 1975:61). However, it was soon

realized that this protection was inadequate and new regulations were implemented. These

safeguards became particularly important after extensive silver deposits were found in Peru

in 1545 (Parry 1966:106). This prosperity was compounded in 1555 when Bartholomew

Medina successfully worked out a procedure using mercury for the amalgamation of silver,

from the mines (Haring 1918:158). This not only facilitated a massive boost in the pro-

duction of silver but forced government officials to consider implementing additional

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regulations ensuring that treasure and other cargo were protected as they made the long,

arduous journey across the Atlantic to Spain.

Simultaneously with the discovery of silver, changes in the manner in which cargo was

transported back to Spain were made. In 1552, the averia and the fleet system were

abolished. In place, the crown now required the owner of a vessel involved in the trans-

portation of cargo from the New World to be responsible for outfitting and protecting his

ships (Peterson 1975:62). During this time, only one private fleet with an armed escort of

four vessels was able to make the journey as war soon broke out between France and Spain

(Franco-Habsburg War, 1551–1559). This war saw the end of privatized fleets and a return

to a fleet system subsidized by the crown to protect the precious cargos leaving the New

World (Peterson 1975:62). From 1564 to 1566, a series of new laws helped reshape the

fleet system providing a structure for the continued trade between Spain and her colonial

holdings until the latter part of the eighteenth century. As the flota system continued to

evolve, the two squadrons responsible for the protection of the fleet between the Caribbean

and the Canary Islands continued to patrol the waters of the Atlantic. Eventually, these two

squadrons were renamed the Armadas de la Guardia de la Carrera de las Indias and were

charged with escorting the fleet and its valuable cargo from the New World to Spain. The

fleet traveling to and from Panama, termed Galeones, was named after the well armed and

constructed galleons. The fleet traveling to and from New Spain (Mexico) was named the

‘‘flota’’ and was protected by two heavily armed warships designated the Capitana and

Almiranta (Peterson 1975:64). Changes to the fleet would occur throughout the remainder

of the colonial period, but its overall structure remained relatively intact until the end of the

empire (Peterson 1975).

The development of the treasure fleet system was, in reality, an evolution of the mer-

cantilist economic polices of the Spanish Crown as well as an understanding of the

environmental constraints and conditions that existed while at sea. Most importantly, this

development was not haphazard in nature; rather, it was a result of trial and error where the

Spanish Crown and, later, private companies developed methods to mitigate smuggling,

piracy, and ultimately losses occurring at sea.

The fleet system

Essentially, the regulations mandated that two separate fleets were to leave for the New

World each year on a prescribed schedule. The fleet would leave Spain (first from Seville

and later Cadiz) from February through September with a peak in July (Chaunu 1977),

along with ships bound for Honduras, Cuba, and Hispaniola, sailing down the coast of

Africa until reaching the Cape Verde Islands. At the Cape Verde Islands, the fleet turned

west, using the prevailing trade winds until they entered the Caribbean. Here the ships

split into two separate fleets, the Nueva Espana fleet and the Tierra Firme fleet (after

1648 this fleet was termed Los Galeones). The first fleet sailed to New Spain’s (Mexico)

port of Veracruz, keeping south of the Greater Antilles, crossing the Yucatan Channel

and sailing along the southern Gulf of Mexico. Arrival at Veracruz occurred in the

summer (Perez-Maillania 1998); but again, Chaunu (1977) found that arrivals occurred

from May through November with a peak in September. The fleets were ordered to

winter in America (Chaunu 1977; Parry 1966; Peterson 1975; Haring 1918). The second

fleet hailed the South American mainland ports of Cartagena, Nombre de Dios, and Porto

Bello (Smith 1988).

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At these ports, the ships offloaded manufactured goods produced in Spain, making

room for the precious and rare cargo of the Indies (Smith 1988). In addition,

commodities from another Spanish fleet called the Manila Galleons crossed the

Pacific, bringing exotic goods from the Orient to the port of Acapulco. Here the

goods were loaded on mule trains and hauled across Mexico to the Caribbean flotas(Smith 1988).

After the fleets were loaded with their cargos, they began the long trip back to Spain.

The Nueva Espana flota left Veracruz from February through August, with a peak in June,

and sailed along a northeasterly route into the northern Gulf of Mexico to the west coast of

Florida (Smith 1988; Chaunu 1977). Here the flota made its way down towards Cuba. The

two flotas would rendezvous at Havana for the voyage home to Spain after the ships were

refitted and made ready. The combined flota departed Cuba sailing north through the Straits

of Florida with the Gulf Stream propelling the ships past the Bahamas and eventually

setting a course for the Azores and Spain (Smith 1988:86). However, a joint convoy was

not always possible because of delays (Peterson 1975).

The flota system reached its height between 1590 and 1600. Over the next century, the

system slowly began to decline, primarily as a result of Spain’s weakened leadership,

enormous debts to foreign countries, continuous privateer attacks on shipping, colonization

of the Caribbean by other European countries, and a reduction in the extraction of precious

metals from colonial mines. By the end of the sixteenth century, the average number of

vessels used in the flota was approximately 100. However, by 1610, the number of vessels

used in the flota system dropped from 55 in 1610 to 25 by 1640. Back home, Spain suffered

economic and industrial decline. The shipbuilding industry began to decline as well and by

1650 more than two-thirds of ships used in the flota system were constructed in foreign

countries. This resulted in a weakened Spanish navy, forcing Spain to hire out foreign

warships to escort the flota home by the end of the seventeenth century. The last flotamaking the trans-Atlantic journey to Spain carrying cargos from the New World sailed in

1779 (Parry 1966).

Methodology

About one-third of the effort, energy, and time invested in preparing this study consisted of

searching and examining reprints of historic maps that depicted routes or derrotas that

colonial ships took between Veracruz and Havana. The literature search yielded maps from

books and online collections of maps by academic institutions or map collectors. Several of

the maps examined were not employed in this work because they are duplicates of other

maps and provided no new or additional information. In total, eighteen maps from late

1600’s to mid-1800 were examined and incorporated into our database of shipping routes.

Since our interest focused only on the shipping routes, the digital maps were stretched over

a modern projection and the routes were digitized. A description of how these maps were

manipulated is presented below. One map in particular was used, as it represents an

original captain’s chart depicting a ship’s route through the Gulf of Mexico. This route is

denoted as Madrid2 in Fig. 1.

Other sources of information pertaining to Spanish sailing routes included sailing

instruction books or derroteros and reports containing sufficient details to allow

reconstruction of the sailing routes. Some of the books and research employed in this

study includes Itinerario de Navegacion (Escalante de Mendoza 1575) and a report

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Fig. 1 Derrotas or routes examined in this study: all routes (A); routes digitized from maps (B);reconstructed routes (C). The route Madrid2 is shown by the heavy dashed path in panels A and C

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from an earlier MMS study entitled Cultural Resources Evaluation of the Northern Gulf ofMexico (Gagliano 1977). Derrotas or routes from sailing instructions were reconstructed

by plotting them over a 1905 Navigational Chart. The accuracy of the routes was checked

against details such as water depths, distances from known coastal areas, and sediment

distributions, all of which are described in the pilot books. The agreement between the

reconstructed routes and the details in the documents provided confidence that our plotted

shipping routes were accurate renditions of the actual routes.

Three sources widely consulted in this work were Chaunu and Chaunu (1955),

Chaunu (1977), and Garcıa-Baquero Gonzalez (1976). These works examined in detail

the shipping routes between Spain and the New World by examining the records of the

Casa de Contratacion (House of Trade) housed in the Archivo General de Indias (AGI)

in Seville. Chaunu and Chaunu (1955) and Chaunu (1977) examined the records from

1550 to 1650 and Garcıa-Baquero Gonzalez (1976) examined those between 1717 and

1778.

Source data

The data used in this study were derived from approximately eighteen non-georeferenced

images of maps with unknown projections obtained from publicly available sources. The

original maps date from approximately 1696 to the 1850’s and, while the latitude of the

original maps was fairly accurate, they contained large errors in longitude. Some maps also

exhibit large gaps of geographical knowledge, as demonstrated by misrepresented or

misplaced land forms.

Rectifying maps

The routes for this project were re-created from the original maps, which were dated before

the mid-1800’s. The original maps were not geographically accurate, had no known

coordinate system, and were not to scale. To re-create the map routes for this project, we

used the major steps outlined as follows:

Using ESRI’s ArcGIS software, each image was georeferenced using several control

points (points that are easily identified in both data sets that have known geographical

coordinates). The primary control points of Veracruz; Havana; and Tampa, Florida,

were selected because their locations were known at the time of the maps’ creation and

they were easily identified on each map. Other features that were identifiable on the

original maps, such as rivers, bays, and coastline segments, were used in the trans-

formation.

The newly georeferenced images were placed over layers of accurate geographical

themes, and the distortion in the routes of the original maps was easily identified. Using the

process known as ‘‘rubbersheeting,’’ (manipulating one set of map data to match another

known set of georeferenced data), the routes were interpolated by using the shapes of the

routes in relation to their location on the original maps to the control points and features.

The original errors in longitude were corrected during this process, allowing us to maintain

proportionate geometry with the known coordinates of Veracruz, Havana, and other control

points.

Finally, all routes were projected to Albers Equal-Area Conic and their distances were

measured.

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Results

Figure 1 shows the routes followed by sailing ships from Veracruz to Havana across the

Gulf of Mexico from at least 1575 until the end of the organized flota system in the late

eighteenth century. All routes started at Veracruz, headed northeast until reaching between

latitudes 258 and 27.58 N, turned eastward until reaching west Florida, then turned

southeastward, crossed the Florida Straits, and reached Havana. These 23 routes are from

historic maps and sailing instructions from Spanish, English, French, American, and other

European mapmakers of the period. The route was first established by the pilot Anton de

Alaminos, who in 1519 returned to Spain from Veracruz by orders of Hernan Cortez during

the conquest of Mexico (Fernandez-Duro 1893; Marmer 1929; Cerezo-Martinez 1994). In

1513, while piloting for Juan Ponce de Leon, Alaminos discovered the route back to Spain

through the Florida or Bahamas Channel and this inspired him to seek the route from

Veracruz to Havana as shown in Fig. 1 (Cerezo-Martinez 1994). The classic Fishery

Bulletin 89 (1954) stated that Spanish ships from Mexico to Havana followed the Gulf of

Mexico’s northern coast, without further explanation.

The most notable aspect of Fig. 1 is the vast extent of the Gulf of Mexico affected

by the routes, which cover almost the entire north-south expanse (from latitude 198 N

to 288 N or *540 nautical miles (nm)) and the entire west-east span (latitude 978 N to

818 N or *961 nm) of the Gulf of Mexico. Figure 1 also reveals that all routes are

over deep waters (i.e., depths >200 m), a new realization for us, but not surprising,

since Spanish vessels were commonly crossing the Atlantic since l492 thanks in part to

the use of the magnetic compass (Cerezo-Martinez 1994). The routes show a large

scatter in the western Gulf of Mexico, which we ascribe to the fact that courses were

set either to the NE or NNE depending on the wind conditions at departure (see for

example Escalante de Mendoza 1575; Gonzales-Carranza 1740; Gagliano 1977). The

northern and eastern portions of the routes exhibit a smaller scatter, which we believe

is because of reduced variation of currents and winds that influenced these segments of

the routes. However, the scatter could also be attributed to the practice of copying and

transposing information between maps, a common occurrence among cartographers of

the period or errors resulted from ‘‘rubbersheeting.’’ Finally, the figure shows evidence

of two clusters of routes, those reaching north to latitude 27.58 N and a second group

around latitude 258 N. The latter cluster is mainly because of routes from sailing

instructions by English and French sources. This cluster could also reflect a seasonal

shift of routes. For example, Gonzales-Carranza (1740) states that in winter one needs

to reach latitude 268 N before turning east, but in summer only to latitude 258 N;

however, Kerhallet (1853), Lopez de Velasco (1894), and the Derrotero de las Antillas

(1849) indicate the opposite, that summer routes are the more northerly ones, and

winter routes the more southerly ones. Peterson (1975) and Haring (1918) indicate that

the route from Veracruz to Havana was along the latitude 258 N route without any

indications of seasonal changes. The important point here is that historic maps are

biased towards the northern route and that Spanish sailors were using both routes.

Table 1 shows distance covered and travel times employed to estimate the speed range

of colonial sailing ships in the western Atlantic waters. The speeds range from 1.5 knots to

a maximum of 8 knots. However, there are two cautionary points regarding vessel speed–

first, winds or currents could reduce speeds by 1–3 knots (Cerezo-Martinez 1988) and,

second, when heavily loaded, speeds could be reduced by up to 25 percent (Escalante de

Mendoza 1575). Recall that vessel speeds were anything but uniform along the routes. On

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the basis of this information and the calculated speeds, the range of 2–6 knots was chosen

as representative of actual conditions to estimate travel time between Veracruz to Havana.

There could have been a trend towards higher speeds near the end of the study period, but

we do not have information to appraise such change. Furthermore, travel times are esti-

mated assuming no tacking, no problems, and uniform speeds; therefore, these values

represent minimum travel times. The other variable needed to estimate travel time is the

route length or distance. The Veracruz-Havana route length, from Fig. 1, varied from a low

of 985 nautical miles (nmi.) to a maximum of 1364 nmi. (range of 379 nmi.), with a mean

of 1170 nmi. and standard deviation of only 89 nmi. The range is about four times the

standard deviation. The distribution is skewed toward high values because our sample of

routes is biased toward the northern or longer routes. The bias arises because very few

maps depicting the southern routes were found. The longest distance represents a route

during wartime (Gagliano 1977). These lengths compare well to reported distances of 992

nmi. (310 leagues) (Escalante de Mendoza 1575) and 960 nmi. (300 leagues) (Peterson

1975) for routes close to latitude 258 N. Estimates of travel times varied from about

24 days at 2 knots to about eight days at 6 knots. In addition, their ranges are relatively

small: seven days at 2 knots, five days at 3 knots; three days at 4 knots, and two days at 6

knots. These travel time estimates agree with those reported in historical sources (Table 2),

which varied from 10 to 87 days. A plot of the travel time versus route length (not shown)

reveals two clusters: one at lengths �1,050 nmi. and the other at distances of 1,150–

1,300 nmi. The plot also reveals that the longest route is an outlier route. These clusters

reflect the obvious fact that northern routes near latitude 27.58 N are longer, while the

southern routes near latitude 258 N are shorter (Fig. 1). Of course, it could be that more

intermediate routes, while present, were not captured by our sampling; but this seems

unlikely, given the navigational practices of the era.

Winds, surface currents, and ship routes in the Gulf of Mexico

It has been established that vessels of the study period attained cruising speeds of 2–8

knots. These speeds are comparable to those commonly observed in oceanic currents and

Table 1 Reported distances and travel times in the western Atlantic employed to estimate the speed ofcolonial vessels

Distance (nm) Travel time (days) Vessel speed (knots) Source

1,190 11 4.5 Escalante de Mendoza (1575)

688 5 5.7 Escalante de Mendoza (1575)

992* 20 2 Escalante de Mendoza (1575)

2,560 28 3.8 Escalante de Mendoza (1575)

2,155 20 4.5 Cerezo-Martinez (1988)

2,155 30 3 Cerezo-Martinez (1988)

–a – 2.6 Chaunu (1977)

–a – 1.5 Chaunu (1977)

– – 2.5–3 Fernandez-Duro (1996)

– – 6–8 Fernandez-Duro (1996)

* Using the shortest route along latitude 258 Na Average speed on the inbound and outbound legs respectively to America

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especially in areas of the Gulf of Mexico such as the Florida Straits, the Bahamas or

Florida Channel, or the Yucatan Channel, where surface currents of 2–3 knots are com-

mon. In fact, sailing instructions from Escalante de Mendoza (1575), Gonzales-Carranza

(1740), Romans (1775), and others warn sailors of the dangers of such currents in the

Florida or Bahamas Channel. Interestingly, no such warnings were found in the literature

for the Yucatan Channel, despite this being an area of strong currents and heavily transited

by colonial ships of the era (e.g., Fernandez-Duro 1893; Cerezo-Martinez 1994). These

current speeds represent up to 50 percent of the ship’s speed and, under light winds,

currents could dominate or dictate the movements of the vessels, as was the case during

Ponce de Leon’s expedition to Florida. Porter y Casanate (1634) states that ocean currents

are one of the main sources of error in colonial navigation; however, it appears that pilots

could account for these errors in their navigation. It seems that an understanding of ocean

currents is critical to comprehend how these routes from Veracruz to Havana came to be. It

must be recognized that sailors from the study period lacked the theoretical knowledge and

observations available to us, and that these routes must have been based on a different

paradigm of the Gulf of Mexico surface circulation. In this subsection, we examine these

routes in terms of our present knowledge of the winds and surface currents in the Gulf of

Mexico. Later, we examine the routes in terms of the knowledge of ocean currents during

the study period.

Sailing ships of the period usually carried both square and lateen sails, so they had some

capability of sailing close to the wind, although generally no closer than 70 degrees off the

wind. Figure 2 shows the mean wind stress field over the Gulf of Mexico during May

(Fig. 2A), June (Fig. 2B), and July (Fig. 2C) (Patchen et al. 1993). As was discussed

earlier, during these months departures for Havana peaked. Figure 2 allows us to examine

the trip in terms of winds for the entire route during the peak departure season. In all three

months, the average winds were favorable to sailing in a north–south direction because the

winds were blowing on a beam reach to the routes or ships at the beginning and conclusion

of the trip. In this regard, the work of Garcıa et al. (2001) is helpful since they examined

the speed of colonial vessels as a function of wind angle of attack and speed. On a beam

reach, or wind blowing at 908 to the ship, typical Spanish ships would have to travel at 0.25

of the wind speed. These are the conditions during the first (near Mexican waters) and third

(near the west Florida coast) legs of the trip; recall that the winds tend to be stronger in the

western Gulf of Mexico. In the west-east or northerly segment of the routes, the winds

were mostly diagonal to the ship (a broad reach) and their speed can be estimated as 0.32 of

Table 2 Reported travel time from Veracruz to Havana

Source Time* (days) Range (days)

Escalante de Mendoza (1575) 20 –

Perez-Mallaina (1997) – 14–21

Parry (1966) – 21–38

Haring (1918) – 18–20

Cerezo-Martinez (1988) 10 –

Garcia-Baquero Gonzalez (1976) 35 25–58

Chaunu (1977) 62 14–87

Hirzy (1992) 15 –

Garcıa et al. (2000) 55 –

* This column represents the average time for the trip

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Fig. 2 Derrotas or routes superimposed on average wind field stress over the Gulf of Mexico in May (A),June (B), and July (C)

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the wind speed. During this eastward leg, the winds became weaker but their angle of

attack allowed ships to reach their maximum speeds (0.32 of the wind speed). Once the

vessels reached latitude 258 N or near Dry Tortugas, the wind speed increased and re-

mained favorable for southward sailing to Havana as ships reached speeds close to 0.25 of

the wind speed. For ships sailing under typical trade wind speeds of about 8 m/s or 15.5

knots, their speed would have varied from 4 to 5 knots, which agrees very well with our

speed range of 2–6 knots used to estimate travel time. This is not the case in winter, e.g.,

October through January (Patchen et al. 1993), when the average winds near Veracruz are

from the north (northers), making departure not only very difficult but even dangerous.

Wind fields similar to those shown herein can be found in Rhodes et al. (1989).

During colonial times, sailors of the Gulf of Mexico avoided two seasons: summer

because of tropical storms and winter because of northers. The present tropical storm

season of the western Atlantic runs from June 1 through November 30; the Spanish

believed that the season ran from July through September, a 50-percent shorter season.

This could explain why some trips occurred during the present-day hurricane season. By

definition, tropical storms have wind speeds greater than 17 m/s (34 knots) and hurricanes

over 33 m/s (64 knots), with measured significant wave heights of 9–18 m. While the

number of tropical storms varies over time, in modern days the Gulf of Mexico experiences

about four tropical storms per year (*18 storm days per year) with the average storm

residing about 5 days in the Gulf of Mexico (Florida A&M University 1988). A pre-

liminary analysis of historic records suggests that the number of hurricanes was fewer than

15 hurricanes per 50 years from 1500 through 1749, then increased until 1898 and reached

a maximum of over 45 in the second half of the eighteen century (Garcıa-Herrera et al.

2004). Furthermore, the frequency of tropical storms is high in the southwestern and

central Gulf of Mexico, affecting the routes in the beginning of the trip. Northers are winds

from the north associated with extratropical cyclones and cold fronts in winter (December

through March). The extratropical cyclone classification starts at wind speeds of over 8 m/s

(16 knots) (Hsu 1993), and wave heights measured during such events reach over 4 m

(Nowlin et al. 1998). The number of extratropical cyclones varies regionally, but over the

northern Gulf of Mexico it reaches about seven events per winter on average, and near

Veracruz it decreases to about two events per winter (Florida A&M University 1988).

Nowlin et al. (1998) report the number of extratropical cyclones varying from 12 to 25

events per month with the maximum in January on the basis of just two winter seasons.

Cold fronts attain a frequency of about nine events per month down to latitude 288 N,

lasting 30–36 h (Florida A&M University 1988). The Derrotero de las Antillas (1849) cites

a frequency of 4–6 days between events of north winds. During such events, the winds are

strong enough to reverse currents (e.g., Gonzales-Carranza 1740) that, coupled with high

waves, would make sailing nearly impossible.

Figure 3 shows an overlay of routes compared to near-surface currents of the Gulf of

Mexico, derived from near-surface drifters deployed between 1989 and 1999 (Nowlin et al.

2001). The figure shows surface currents as annual averages (Fig. 3A), summer averages

(Fig. 3B), and winter averages (Fig. 3C). This gross partition is because of the limited

number of observations available. As can be seen, the routes avoid the counter-currents

present throughout the year near the southern Mexican coast. Further, the routes seem to go

around a large clockwise vortex centered near latitude 258 N and longitude 908 W.

Summer currents near Veracruz, while stronger, are mostly perpendicular to the routes,

meaning that they did not help or oppose the wind-induced forward motion of the vessel.

As the routes turn eastward, the currents become more favorable but weaker; however, the

winds are still favorable for sailing. When the routes turn southeastward, the currents

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Fig. 3 Derrotas or routessuperimposed on average surfacecurrents derived from near-surface drifters in the Gulf ofMexico: annual field (A);summer (B), and winter (C)

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increase in speed and become more favorable to the forward motion of the vessel, even if

the winds were at their minimum strength. This condition persists through the middle of

the Florida Straits, where the currents become easterly. In winter, the currents near Ve-

racruz are southward or against the ship’s forward motion until latitude 218 N, where the

currents become more northerly and more favorable to the ship’s northward motion. But as

the ships turn eastward, the currents decreased in speed and even opposed the progress of

the vessel for a short interval. Afterwards, the currents become southeasterly and favorable

to the ship’s progress until the Florida Straits are reached, where they become easterly.

From the standpoint of winds and currents, the routes followed by Spanish sailing

vessels are the most favorable to make the voyage from Veracruz to Havana in the shortest

time in summer. Further, the trips were timed to avoid the hurricane season, which they

regarded as starting in July, and the winter northers. While this discussion demonstrates

how well the Spanish routes were charted and the trips timed with respect to modern

understanding of winds, currents, and storms, their planning could only guarantee a certain

degree of success in navigation because winds and currents exhibit large variations around

the mean climatology.

Effects on the OCS

Figure 4 shows the sailing routes overlaid on oil and gas protraction areas in US Federal

waters of the northern Gulf of Mexico. The routes pass over 23 of these protraction areas,

but only 16 of these are of concern. The areas of interest are in water depths greater than

350 m with active leases and exploration and production activities. Those areas east of the

north–south line near longitude 868 W are of no concern since these have no active leases

or activities related to oil and gas. Regardless of this, from the archeological point of view

these still could be areas of high risk. However, the areas of Garden Banks, Keathley

Canyon, Green Canyon, Walker Ridge, Mississippi Canyon, Sigsbee Escarpment, Amery

Terrace, Atwater Valley, Lund, Lund South, De Soto Canyon, Lloyd Ridge, Henderson,

and Florida Plain are of interest and potentially high probability for having ship casualties

of this period within their submerged bottom lands. Although most routes lie far offshore,

one route does approach close to the coastline, but this occurs near Florida, where oil and

gas activities are not occurring.

The MMS has contracted three studies (Gagliano 1977; Garrison et al. 1989; Pearson

et al. 2003) aimed at modeling areas in the Gulf of Mexico where historic shipwrecks are

most likely to exist. The purpose of these models is to limit the requirement for detailed,

high-resolution acoustic and magnetic survey of the seabed (specified at present in Notice

to Lessees and Operators 2005-G07) to those areas most likely to yield positive results. The

first two studies concentrated almost exclusively on analyzing primary and secondary

historical sources to posit likely loss areas for historic shipwrecks. As a result, the greatest

concentrations of wrecks were thought to be either close to shore or within a 7.2-km radius

of their reported loss positions. Consequently, some lease areas in deepwater were des-

ignated erroneously as having a high probability for the location of shipwrecks on the basis

of faulty historical data, while most deepwater blocks had no archaeological survey

requirements whatsoever (Irion 2002). The Pearson et al. (2003) study benefited from the

experience of almost 15 years of high-resolution, shallow-hazard surveys in lease blocks

and along pipeline routes. Some of these surveys (almost exclusively for pipeline routes)

were conducted in deepwater. Several of these pipeline hazard surveys succeeded in

locating historic ships, ranging in age from an eighteenth-century armed sailing ship (Irion

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2006) to a World War II German U-boat (Church et al. 2007). Historic shipwrecks have, to

date, been discovered through oil industry sonar surveys in water depths of up to 1,981 m.

Many of these wrecks were not previously known from the historic record to exist in these

areas. Taking these discoveries into account, the Pearson et al. (2003) study then recom-

mended including some deepwater areas, primarily on the approach to the Mississippi

River, among those lease areas requiring archaeological investigation.

With this investigation, new information has come to light, suggesting a higher potential

for early (sixteenth-eighteenth century) shipwrecks in the deepwater areas than previously

suspected. The MMS studies to date have largely discounted the presence of exploration or

colonial period shipwrecks in significant numbers in the Gulf of Mexico because of the

paucity of reported shipwrecks from those periods in the secondary literature. The few

early wrecks that have been discovered and reported in the central and western Gulf were

associated with hurricanes or storms that drove them into the shallow waters on the coasts

of Texas (viz., the 1554 Fleet) and Louisiana (viz., El Nuevo Constante). What has not

been explored thoroughly are losses associated with causes other than wrecking or

stranding (such as fire, structural failure of the hull, foundering, or armed attack) that

would have caused a ship to sink far from land. Since the likelihood of anyone surviving

such a catastrophe at sea also diminishes considerably, the likelihood of its loss site

being accurately reported is almost nil. Generally, such ships would be reported as simply

‘‘lost at sea.’’

Fig. 4 Derrotas or routes overlay on oil and gas lease protraction areas in US waters. Note that the southernroutes are outside American waters except in the southeastern Gulf of Mexico

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Losses of ships on the Veracruz-Havana route are poorly understood. From the works of

Chaunu and Chaunu (1955), Garcıa-Baquero Gonazalez (1976) and other sources, we

assembled Table 3, which contains a partial listing of ships, drawn from those and other

sources, that were lost between Veracruz and Havana somewhere in the Gulf of Mexico.

Table 3 shows that 14 shipwrecks occurred over the deep Gulf of Mexico during the study

period. This list, however, should not be considered exhaustive. While the cause of loss of

each ship is not available, it would not be a stretch of the mind to assume that most were

related to hurricanes or storms. Recent findings on hurricane and storm activity in the

sixteenth to eighteenth centuries for the western Atlantic based on records at the AGI

(Garcıa-Herrera et al. 2004, 2005), reveal that this period experienced high hurricane/storm

activity, but the seventeenth century did not. The number of hurricanes/storms was highest

in 1576–1601, 1610–1626, 1726–1730, and 1760–1780 (Garcıa-Herrera et al. 2005). Also

interesting and informative is the monthly distribution of hurricanes and storms. As ex-

pected, hurricanes were most frequent during September, but hurricane activity was still

high in October and dropped fast in November through December (Garcıa-Herrera et al.

2005). The storm distribution shows two peaks, winter and summer, reflecting, as ex-

pected, the main types of storms in the Gulf of Mexico: extratropical in winter with a peak

in February instead of January, as reported earlier, and the tropical storm season in summer

with a peak again in September (Garcia-Herrera et al. 2005). Examination of Table 3

reveals that 8 out of 14 shipwrecks occurred during the 1576–1601 period, 3 of 14 occurred

in 1610–1630, and 2 of 14 in the 1726–1730. A corresponding peak is not evident for

1760–1780, but examination of the shipping data (Garcıa-Baquero Gonzalez 1976) reveals

that only five convoys sailed during 1717–1778; data is absent for the remaining two years.

Shipping data from Chaunu and Chaunu (1955) and Chaunu (1977) reveal that convoys

were sailing regularly from 1550 to 1650, but that was not the case between 1718 and 1778

(Garcıa-Baquero Gonzalez 1976). There is a data gap of 68 years between 1650 and 1718

when no information on sailing convoys was found in the published literature. The

available data suggest a correlation between shipwrecks and hurricane activity. We

examined the correlation between the number of hurricanes and duration of the trip from

Table 3 Ships lost between New Spain (Mexico) and Havana, provenance unknown

Year lost Name of ship Name of master Type of ship

1562 Unknown Pedro Menendez nao

1567 N.S. de los Remedios Lazaro de Rosas nao

1573 La Madalena Cristobal Sanchez nao

1586 Unknown barco con situado

1592 Nao de Diego Felipe Andino nao

1592 Nao grande de Granillo nao

1592 Nao de Miguel de Alzate nao

1595 El San Crucifixo de Burgos Pedro de Madariaga galleon

1600 Unknown Diego Rodriguez nao

1606 Unknown Pedro de Izaguirre frigate

1615 Candelaria Juan Estevan nao

1719 S. Juan Bautista frigate

1725 S. Bartolome ‘‘El Cambi’’ unknown

1730 Constante ship

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Veracruz to Havana and found it to be very low (0.08). Coincidence of shipwrecks with

periods of high hurricane/storm activity might not be a cause-effect relationship, but it

suggests that shipwreck activity is related to hurricane/storm activity, while trip duration is

not. These correlations should be explored in more detail by using larger databases.

Knowledge of winds and currents in colonial times

It has been established how well modern climatological wind and current fields in the Gulf

of Mexico clarify and justify the path and timing of the Veracruz-Havana shipping routes.

But as stated previously, colonial sailors lacked the theoretical, technological, and

observational knowledge of winds and currents available today. So, what was their

understanding of the winds and currents then? Before this question is answered, a historical

context needs to be provided. The study period (1775–1800’s) was one during which the

Aristotelian view had to be abandoned for one that accounted for new knowledge and

understanding gained from travels, observations, experiences, and technological advances.

Therefore, this was a time of transition and evolution in almost every human endeavor.

Peterson et al. (1996) present an excellent review of these changes in oceanography and

navigation. To start answering the previous question, these navigators’ understanding of

the general patterns of winds and currents was fairly accurate, when one considers that

their knowledge consisted of *75 years of observations from ships by the time of Es-

calante de Mendoza’s (1575) book. Recall also that during this time the problem of

longitude made observation from ships very difficult and inaccurate. The Spanish sailors’

knowledge of the trade winds and westerly winds was fairly good; in fact, judging by the

map of Popple (1733) and others, they thought that the trade wind field had sharp

boundaries and did not cover the entire Gulf of Mexico. In this sea, the wind field covers its

center in the shape of a tear and excluded the coastlines. Notation over the route in

Popple’s (1733) map and others indicates that the routes were designed to avoid the

southwestward trade winds. A similar statement is related by Romans (1775). Several other

maps of the late 1700’s and early 1800’s provided a similar representation of the trade

wind field: a tear shape mainly over the center of the Gulf that excluded the coastlines.

While the pattern was empirically known, what the Spanish sailors lacked was theoretical

understanding of the trade winds, but this was not to come until the late 1800’s (see

Peterson et al. (1996) for discussion of this topic).

The Spanish navigators’ knowledge of the ocean’s currents is easier to assess because,

despite the lack of maps depicting their conception of the flow field, they provided two

detailed descriptions about 160 years apart of the Caribbean and Gulf circulation (Esca-

lante de Mendoza 1575; Gonzales-Carranza 1740). Figure 5 shows our interpretations of

the surface flow descriptions from these sources. As readers can appreciate, Spanish sailors

had a fairly good knowledge of the general circulation of the Caribbean Sea and the flow

through the Florida or Bahamas Channel, which we know as the Gulf Stream system (c.f.,

Fernandez-Duro 1893; Cerezo-Martinez 1994). They understood well that the currents

flowed westward through the Caribbean Sea and that these currents reached the Yucatan

coast and were deflected northwards across the Yucatan Channel (Fernandez-Duro 1893;

Cerezo-Martinez 1994). A problem identified during this study pertains to the flow inside

the Yucatan Channel. For example, Fernandez-Duro (1893) and Derrotero de las Antillas

(1849) indicate high speeds inside the Channel; however, others say that the speeds are

small (Rennell 1832). Aside from this problem, the circulation agrees well with our present

knowledge of currents in the Caribbean (c.f., Gordon (1967) for a comparison). The big

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difference, however, occurs inside the Gulf of Mexico! The descriptions indicate that they

thought the currents turn westward upon entering the Gulf and flow along the coast all the

way around until becoming the outgoing current at the Florida Straits (Escalante de

Mendoza 1575; Gonzales-Carranza 1740; Lopez de Velasco 1894). This pattern is shown

in several maps found in sources such as Maury (1855), maps by de Fer (1702) and Dudley

(1661) both in Cerezo-Martinez (1994), a pilot chart by Kerhallet (1853), a chart by

Garcıa-Cubas (1885), and many other maps in Peterson et al. (1996). Pillsbury (1890)

states that the common view of the currents in the Gulf of Mexico is that a portion of the

Fig. 5 Surface circulation of the Caribbean and Gulf of Mexico, reconstructed from descriptions inEscalante de Mendoza (1575) and Gonzalez-Carranza (1740). Arrows represent direction of flow only sincespeeds were not reported or, more accurately, not observed

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waters turn to the Florida Straits after entering the Gulf and that the remaining water turns

west and goes around the Gulf of Mexico until merging with the outflow at the Florida

Straits, a view shared by Rennell (1832). A 1914 chart by Soley (in Fishery Bulletin 89

1954) depicts three main currents inside the Gulf: a Gulf Stream gyrating around the Gulf

and exiting through the Florida Straits; an eastern branch that enters the Gulf and turns

immediately towards the Florida Straits; and a northwestern branch that intrudes the Gulf,

rotates anticyclonically, and exits through the Florida Straits. A chart in Chaunu (1977)

shows that some of the waters entering the Gulf of Mexico go north and turn east to exit via

the Florida Straits; another portion goes mainly west and becomes a vortex that is joined by

a third fraction that flows northwestward. The map does not show how the waters in the

western basin leave the Gulf of Mexico. The Chaunu (1977) map resembles two current

charts shown as Figures 34 and 35 in Fishery Bulletin 89 (1954) that suffer from the same

mass conservation problem. By the mid-1800’s it was no longer accepted, at least by some,

that waters entering the Gulf of Mexico flow westward along its perimeter, as descriptions

in Rennell (1823:150) and Derrotero de las Antillas (1949:401) indicate. Comparing old

depictions of the circulation in the Gulf of Mexico with that shown in Figure 3A reveals

that the colonial sailors were missing what is at present known as the Loop Current. This

high-speed current flows northward into the Gulf of Mexico through the western half of the

Yucatan Channel, turns clockwise, and exits through the Florida Straits, carrying most of

the influx of Caribbean water (Fig. 6). The Loop Current reaches speeds of 1.5–2.0 m/s,

carries 23–27 million cubic meters per second of water, and reaches up to latitude 288 N

inside the Gulf (Schmitz et al. 2005; Lugo-Fernandez in press). The Derrotero de las

Antillas (1849: pages 399–400) gives a description of the flow inside the Yucatan Channel

resembling our modern view of this current.

The early Spanish paradigm of currents in the Gulf of Mexico also makes the layout of

the routes logical. In fact, examination of the annual current map (Fig. 3A) reveals that

hypothesizing that the currents move around the Gulf of Mexico is a plausible interpre-

tation of the circulation. Only detailed observational studies, calculations of volume flux,

and modern numerical circulation models have revealed the circulation inside the Gulf.

Therefore, the Spanish paradigm of the Gulf’s circulation was probably justified on the

Fig. 6 Schematic representation of the Loop current in the Gulf of Mexico on the basis of modernunderstanding of this important current

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basis of their oceanographic knowledge and observations of currents. But given the

experience gained during 300 hundred years of sailing in the Gulf of Mexico, the question

remains, how could these sailors miss the Loop Current? Two possible explanations are the

bias caused by the scheduling, which allows observation mainly during summer, and the

bias introduced by the routes themselves, which prevented observing the area of the Loop

Current. To the colonials’ defense, modern oceanography did not identify the Loop Current

until sometime between 1935 and the 1950’s; in his study of the Gulf of Mexico, Parr

(1935) did not mention this current but claims that water from the Caribbean takes the

shortest route to the Florida Straits with appreciable penetration inside the Gulf.

Discussion

This work examines the navigation route followed by Spanish vessels from Veracruz,

Mexico, to Havana, Cuba, across the Gulf of Mexico from 1575 to late 1800’s. Our route

database was assembled from historic maps and texts readily available; we did not have

access to the primary sources. While we do not know the basis for the mapmakers’ rendition

of the routes, it is apparent that these depictions are not just artistic renditions. We believe

that factual information was employed, and perhaps copied among them, in the routes’

portrayal to make their maps truthful and accurate within their limitations. Agreement

between the maps and reconstructed routes (Fig. 1) lends support to our claim against just

artistic renditions. Furthermore, Fig. 1 reveals a bias of the mapmakers for the northern

branch against the southern branch; only one of the maps showed the southern route. The

navigation texts revealed this branch of the route. Thus, we believe that we uncovered

sufficient and accurate information about the nature of the route employed by the Spanish in

their travels across the Gulf of Mexico. However, we could not assess the evolution and

refinements made to the route as new knowledge and experience were gained.

Spanish vessels navigated annually, as circumstances allowed, between Spain and

Mexico and returned to Spain via Havana. It is the first leg of the return trip, Veracruz to

Havana, that we examined in detail. The return leg consisted of two branches depending on

the wind direction at departure. The long or northern branch consisted of an arch that went

to latitude 27.58 N, then east, turned southeast near Florida until reaching Dry Tortugas,

and headed south to Havana through the Florida Straits. The second or southern branch

went only to latitude 258 N, proceeded east until the Dry Tortugas, and reached Havana,

similarly to the long route. The basic route pattern was established by Anton de Alaminos

in 1519 during his return trip to Spain to inform the King about the progress of the Mexican

conquest. No doubt that subsequently the route was refined but we could not evaluate this

aspect. The northern route had an average length of 1,170 nmi., while the southern route

had a length close to 985 nmi; both seemed equally important on the basis of the navigation

textbooks. The entire trip was over the deepwater (depths >200 m) of the Gulf, a fact not

surprising in light of the transoceanic travels of the era. The route length was covered in an

average time of 8–24 days, but reports suggest durations as high as 38–58 days with an

extreme of 87 days. Following the route was not a guarantee of a successful trip, but its use

over 350 years suggests that it was a highly advantageous route over which to conduct their

commerce, despite how widely known and predictable it was to Spain’s enemies.

The route, especially the northern branch, crosses over 16 OCS planning areas in which

oil and gas activities occur at present. Regulations governing the development and

exploration of petroleum resources require that the effects of these activities upon

archeological resources be considered during the permit processes. The results of this work

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suggest that there is a significant probability that ships from the study period could be

found in areas depth’s of greater than 350 m under consideration by the oil and gas

industry. As Table 3 shows, 14 wrecks could be found in the deep waters of the Gulf of

Mexico. There is a good chance that more records of losses could be found in the Gulf if

the primary sources were consulted. Further study of primary sources is required to

determine if vessels were lost along this portion of the route, as opposed to waters closer to

Mexico, Florida, or Cuba.

Examination of historical events or conditions can always fall in the trap of basing the

analysis on current knowledge and not on the understanding of the time when the event

took place. In this study, we analyzed the Veracruz-Havana route under our present

knowledge of wind and current patterns and those during the study period. Under both sets

of knowledge, the pattern of the routes and timing of the trip were well designed. In fact,

the routes’ design was refined with considerations of the climatic conditions of the starting

and final destinations (Escalante de Mendoza, 1575). As such, the Spanish had a good

working knowledge of the hurricane season and the winter winds in the Gulf of Mexico;

however, that knowledge was still incomplete when compared with our modern knowl-

edge. Examination of their knowledge of the Caribbean and Gulf circulation reveals that it

resembles the large-scale aspect of our present understanding of the Caribbean, but departs

significantly in the Gulf of Mexico. In the Gulf, their paradigm of currents indicates a

strong flow entering through Yucatan, turning west and flowing along the entire perimeter

of the Gulf until exiting by the Florida Straits.

However, this pattern was evolving and approaching the modern view as observations

and knowledge increased over time. At present, we know that the flow across the Yucatan

Channel flows northward as a strong jet, turns clockwise near the Florida Peninsula without

extending farther west than about longitude 918 W, and exits across the Florida Straits. A

second branch seems to flow from Campeche around southern Mexico and north to the US,

where it flows eastward as a diffuse current. So the natural question is: Is the circulation

difference caused by interpretation and lack of data or was it real? The question is con-

founded by the fact that the study period coincided with the Little Ice Age.

We studied this difference and are proposing the following explanation: The interpre-

tation of the sailors’ observations of currents suggested the westward flow pattern could be

done from modern current fields (Fig. 3A), since their theoretical knowledge suggested that

flows continue until reaching a barrier and turning. This interpretation was reinforced by

the biases of the scheduling and routes of the trips, which prevented sampling the Loop

Current region. It was not until the advent of the chronometer, which allowed accurate

determination of longitude, that the accuracy of current observations increased to allow

distinguishing patterns better (Peterson et al. 1996). However, it took at least another

50 years before modern scientists identified the Loop Current. If there are any changes by

the Little Ice Age on the Gulf of Mexico circulation, it is hard to distinguish these effects in

the databases and literature available to us.

Conclusions

The main findings of this work are as follows:

1. Spanish vessels were crossing the Gulf of Mexico from Veracruz, Mexico, to Havana,

Cuba, at least annually for over 350 years; these trips took place over deep waters by

using a route that went north to latitude 27.58 N or to latitude 258 N and lasted from 8

to 24 days on average, but could last up to 87 days.

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2. The route layout was optimal with respect to wind and ocean current fields, in terms

that it avoided areas that could delay the trip and used areas that helped with the

speedy crossing of the Gulf. The trips were scheduled around their knowledge of

winds and the hurricane season.

3. The routes crossed the portion of US waters where oil and gas activities are currently

taking place. This realization could potentially bring the oil and gas industry in contact

with a shipwreck of this period. Further study is needed to determine the likelihood of

such an occurrence.

4. Analysis of the current pattern in the Gulf as understood by the sailors of the study

period suggests that it differs from our present understanding of this circulation. We

hypothesized that such differences are caused by incomplete data and different

interpretations of the observations of currents because of their theoretical understand-

ing of oceanography.

Acknowledgments The authors appreciate the support of the US Department of the Interior, MineralsManagement Service, Gulf of Mexico OCS Region during the preparation of this manuscript. The opinionsexpressed by the authors are their own and do not reflect the opinion or policy of the US Government.

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