Chapter 54: The Clinker-built Fu Ship versus the Sailing Warship

Unlike what many people imagine, sailboats powered by wind—whether soft sails or hard sails—can actually sail against the wind. This is possible not because the wind directly pushes the sails, but due to the principles of Bernoulli fluid dynamics.

When the wind blows at a slight angle toward the sail—a position known as the "angle of attack"—the sail curves into an arc. This creates a difference in airflow speed on either side of the sail. Those who have studied physics know that the faster the airflow, the lower the pressure. As a result, the sail naturally generates a lateral force toward the leeward side, operating on the same principle as airplane wings.

At present, the wind on the sea is coming from due north. The Zhang Fushun can sail at a course 30-40 degrees east or west of north, facing into the wind. This posture, hugging the wind at the closest possible angle, is called "close-hauled sailing."

The sailboat alternates between tacking left and right, advancing by zigzagging against the wind. Theoretically, the better the vessel’s seaworthiness, the smaller the angle of this zigzag, and by the Pythagorean theorem, the faster its upwind progress.

“Heave-ho, heave-ho...”

The crew aboard the Fujian ship, under the direction of the first, second, and third mates, together turned the winches to adjust the sails at a wide angle. The sailors handling the rigging on the wind-powered warship, under the boatswain’s command, adjusted a maze of running lines, using the masts as pivots to transform the square sails into fore-and-aft sails. Both ships began to beat upwind in concert.

From high above, the two vessels cut through the snowy waves, each carving a perfect white arc across the sea. It was clear that the hard-sailed Fujian ship, Zhang Fushun, traced a smaller radius, with a narrower angle to the north wind, demonstrating superior sailing capability.

The north wind, laced with snowflakes, struck Wang Cheng’s face, whitening his hair and freezing his furrowed brow.

“Hard sails really do allow for more flexible wind angles. But compared to the wind-powered warship, its masts are shorter and weaker, and the hard sails themselves don't bear much force. In fair winds, it can't outrun the larger, more wind-catching carracks and galleons; in non-upwind conditions, it's barely distinguishable from composite soft sails; but in upwind or variable wind scenarios, it excels, thanks to the hard sails’ wide-angle rotation, achieving an ‘eight directions’ effect. The only advantage I can exploit now is its ability to beat upwind—Zhang Fushun’s sole slim chance for survival!”

For half an hour, the two ships chased each other relentlessly. Zhang Fushun, leveraging its hard sail advantage, managed to seize the windward position by a narrow margin.

The pursuing wind-powered warship, Ziying, immediately slowed down. As the wind passed over the windward Zhang Fushun, its masts and rigging disrupted the airflow, creating a chaotic “wake” like a boulder in a river.

The leeward warship was now caught in this turbulent stream, naturally losing maneuverability. This is the classic opening tactic of naval combat: beating upwind! Once positions are set, it’s very hard to reclaim the windward advantage.

“Captain, their helmsman made no mistakes, clinging tightly to their only chance. Ziying likely won’t capture them anytime soon. Should we change targets?”

The vice-captain, Tanaka, with his signature samurai topknot, spoke in his native tongue, accompanied by an interpreter in a hooded cape. Clearly, this was a hastily assembled team for the pursuit, with little opportunity for coordination; most of them probably didn’t even know their true superior.

Yet their professional competence was unquestionable.

Tanaka was absolutely right. In this situation, if the windward ship is outmatched, it can escape by tacking upwind, while the leeward ship, trapped in turbulence, will fall further behind. If the leeward ship is outmatched, it cannot escape—the turbulent flow slows even its downwind speed. Of course, this latter scenario was impossible: Ziying could only achieve victory or overwhelming victory, never be defeated by a mere fishing boat.

Captain Cui Sheng realized this, too. Chasing Han Xingfa would be easy with a fair wind, but the ship before him might never be caught. Continued pursuit would not be as effortless as imagined; it could easily become a drawn-out ordeal.

Before he could decide, Wang Cheng made the choice for him.

Zhang Fushun had neither cannons nor even the most rudimentary bowl-mouth gun or heavy falconet.

Wang Cheng stood at the bow, gripping the only heavy crossbow he’d salvaged from Yuegang’s ghost market. He affixed a wind talisman drawn by his master to the anchor-shaped bolt, meant for fighting sea monsters, and locked his gaze on a figure aboard Ziying. He pulled the trigger.

Whoosh—

The giant crossbow snapped, blasting a hole through the swirling snow. The bolt, as long as a spear, shot forth with tremendous force. The wind talisman burned out instantly, a whirlwind wrapping the shaft, spinning it at high speed with a piercing howl.

Like an unstoppable drill, it traversed nearly a hundred yards in an instant, piercing the helmsman's chest and pinning him against the stern castle.

The helmsman’s eyes widened in disbelief. His throat emitted two strange rattles, and with a twist of his neck, he was dead.

“Urakami—!”

“Hurry! Chase them down! Kill them all, avenge Urakami!”

A chorus of samurai cried out.

The helmsman was one of the most crucial technical roles aboard, far more important than an ordinary sailor.

Before Captain Cui Sheng could speak, the enraged samurai crew, led by Vice-Captain Tanaka, swung the bow around and resumed the pursuit of Zhang Fushun.

Behind them, Han Xingfa had vanished into the snowstorm, lost from sight and impossible to track.

Cui Sheng saw this and his expression darkened, but there was nothing he could do. Next spring, when the weather in the East Sea improved, the Five Peaks Banner would launch a full assault on the prefecture under the pretext of avenging the Sea King, Wang Zheng. His superiors dared not risk exposing their own men, relying instead on these samurai, which inevitably led to poor coordination.

Cui Sheng could only comfort himself:

“It’s not a problem. With Ziying here, the outcome won’t change—they’ll die sooner or later; it’s only a question of when. The Han family’s young lady still carries monkey hair on her ship, enough for me to use a curse to lock onto their location. Eventually, I’ll catch up.”

The Ziying wind-powered warship was thirty-nine meters long, with a crew of nearly two hundred. It had a full-length gun deck fore and aft, equipped with twenty twelve-pounder cannons, and an open deck with twelve six-pounders—a total of thirty-two guns.

For comparison, the largest cannon of the Imperial Navy was eighteen-pounder; most pirate vessels used three-pounder falconets as their main artillery.

A single Ziying, one-on-one against an ordinary Fujian ship, would be a massacre. The Imperial Navy was not worth mentioning; only the main fleets of famed pirates or armed merchant lords from the East Sea or Southern Seas could stand up to it.

Cui Sheng believed that nobody could be flawless forever; all he needed was one opportunity to crush them utterly...

Whoosh!

Another bolt tore through the air, grazing his temple and nailing a samurai crewman to the deck, leaving a savage gash on Cui Sheng’s cheek.

“Ah—!”