They turned Lake Texcoco from the Spaniards’ chief vulnerability to their greatest asset

From Carnage and Culture by Victor Davis Hanson. Page 227.

Hanson's claim is made in strong form which is at least arguable, but I suspect directionally correct.

It is popular to suggest that natural resources alone determine cultural or military dynamism. If true, we should remember that the Aztecs were sitting atop a war merchant’s bonanza—an entire subcontinent replete with the ingredients of gunpowder, iron, bronze, and steel. In truth, it was the absence of a systematic approach to abstract learning and science, not the dearth of ores or minerals, that doomed the Aztecs. They lacked wagon wheels perhaps because of the absence of horses; but they were also entirely without other wheel-based instruments of war and commerce—wheelbarrows, rickshaws, water wheels, mill wheels, pulleys and gears—because there was neither a rational tradition of science nor a climate of disinterested research.

Nowhere was the rational Spanish approach more apparent than in their ad hoc construction of battle machinery, which followed siege and ship designs dating back to classical antiquity. During the bitter fighting on the eve of the Noche Triste the Spanish within a few hours constructed three manteletes, portable wooden towers that protected harquebusiers and crossbowmen who fired over the heads of the infantrymen. When Cortés next discovered that the causeways were breached, he ordered movable bridges built—a European specialty that dated back to Caesar’s campaigns in Gaul and Germany. After the flight from Tenochtitlán, gunpowder was fabricated, sulfur being drawn from the nearby “smoky mountain” (Mount Popocatépetl, 17,888 feet above sea level). Native metalsmiths were given Spanish designs and instructions to assist in the making of more than 100,000 copper arrowheads for their own bows, and another 50,000 metal bolts for the Spanish crossbows. In an effort to save powder, during the final siege a gigantic catapult was even fabricated—the mechanics of its winch, armature, and springs apparently being misdesigned by amateurs, since it proved ineffective.

The most impressive project was Martín López’s brilliant launching of thirteen prefabricated brigantines. These were enormous galleylike boats more than forty feet long and nine feet at the beam, powered with sails and paddles, and yet with flat bottoms that drew only two feet of water and were thus especially designed for the shallow and swampy waters of Lake Texcoco. Each held twenty-five men and could carry a number of horses, as well as a large cannon. To craft such ships, the Spaniards drafted thousands of Tlaxcalans to haul lumber and the iron hardware salvaged from their beached ships at Vera Cruz. Then López had his carefully organized native work gangs entirely dismantle the brigantines and transport them over the mountains in a large column of some 50,000 porters and warriors to Lake Texcoco. When they arrived in the dry season at Tenochtitlán, López engineered a canal twelve feet wide and about the same depth, through which to navigate the ships from the marshes into deeper waters of the lake: 40,000 Tlaxcalans were involved in the latter project for seven weeks.

The brigantines proved the deciding factor in the entire war, as they were manned by a third of the Spanish manpower and were allotted nearly 75 percent of the cannon, harquebuses, and crossbows. The ships kept the causeways free, ensured that the Spanish camps were secure in the evening, landed infantry at weak points in the enemy lines, enforced a crippling blockade of the city, systematically blew apart hundreds of Aztec canoes, and transported critical food and supplies to the various isolated Spanish contingents. They turned Lake Texcoco from the Spaniards’ chief vulnerability to their greatest asset. Their high decks prevented boarding and gave ample cover for the harquebusiers and crossbowmen to fire and reload—characteristic of traditional Western skill in combined infantry and naval tactics:

However, in the final analysis, Tenochtitlán had an importance that cannot be assigned to Salamis: Tenochtitlán was synonymous with final victory, the conclusion of a war; Salamis was not. At Salamis a civilization was challenged; at Tenochtitlán a civilization was crushed. Possibly in all history there is no similar victorious naval engagement that concluded a war and ended a civilization. (C. Gardiner, Naval Power in the Conquest of Mexico, 188)

The brigantines, despite being fabricated more than a hundred miles from Lake Texcoco, proved to be far more ingeniously engineered for fighting on the Aztecs’ native waters than any boat constructed in Mexico during the entire history of its civilization—a feat possible only through a systematic approach to science and reason that had been ubiquitous in the West for two millennia.