Soon after Vice Admiral Courbet’s proclamation of the blockade of Taiwan, the Imperial Court in Peking demanded action to be taken in order to relieve it. Thus, orders were given to the commanders of the Peiyang and Nanyang districts – Li Hung-chang and Tseng Kuo-ch’uan. After the annihilation of the Fukien Fleet, the Nanyang Fleet was most suitable to lift the blockade of Taiwan, but Tsen Kuo-ch’uan was unwilling to risk ‘his’ warships in the coming operation without participation of the Peiyang Fleet ships. After long-lasting arguments, both Li and Tseng decided to detach five warships from their respective fleets, and send the squadron thus created to the coast of Taiwan.
Tseng Kuo-ch’uan detached the cruisers K’ai Chi, Nan Ch’en, Nan Shui and Yu Yuan as well as the small cruiser Teng Ch’ing for the planned operation. Li Hung-chang ultimately sent only two small cruisers, Chao Yung and Yang Wei, instead of the promised five warships. The two cruisers arrived at Shanghai at the beginning of December 1884. For Li, the situation in Korea was a priority, compared to which the conflict with France was less important. Meanwhile, in December 1884 a pro-Japanese coup d’état was attempted in Seoul. It was suppressed with help of Chinese troops, but the situation was exacerbated to such an extent, that on December 10, Li Hung-chang requested the Tsungli Yamen to relieve both cruisers from the planned mission.
The arguments made for the withdrawal of the two ships were not without grounds. Chao Yung and Yang Wei were, despite their relatively small displacement, very modern warships of substantial fighting strength, so the Tsungli Yamen suggested sending to Korean waters the older vessels Yu Yuan and Teng Ch’ing. However, Li, not waiting for the Tsungli Yamen’s reply, ordered ‘his’ warships to leave Shanghai, which they immediately did, returning to Port Arthur. Consequently, only the aforementioned five vessels of the Nanyang Fleet took part in the operation against the French squadron blockading Taiwan. Admiral Wu An-k’ang assumed command of the squadron, while Vice Admiral Ting Ju-chang, Li Hung-chang’s ‘man’, detached from the Peiyang Fleet became the second in command.
In preparation for the operation, at the end of December 1884, Wu’s squadron departed Shanghai for Wusung to perform gunnery drill. Soon thereafter, the Chinese warships sailed to Chusan. After two weeks spent on further gun nery practice, at the end of January 1885 they headed south. Admiral Wu was not in a hurry, as a result, the Chinese squadron arrived at Nankou only on January 25. The next day it reached Yuehnan, 200 NM north of Foochow. Admiral Wu next made for Wenchow, which he intended to use as a base for further operations. However, instead of taking decisive action, the Chinese commander began to cruise, unproductively, along the coast of the Chekiang province, clearly in fear of an encounter with the French warships.
At the end of January Vice Admiral Courbet received the first piece of intelligence concerning the dispatching of the Chinese squadron to relieve Taiwan. It was transmitted by Captain Baux, the commander of the armoured cruiser Triomphante, then stationed in Hong Kong. The notification was soon confirmed by news reports, on February 3, so Courbet sent orders to the commanders of Triomphante and Nielly that the French naval forces should be concentrated at Matsu, at the mouth of the Min River, where he arrived himself with Bayard, Ėclaireur, Aspic and Saône three days later. Soon thereafter, that force was joined by the cruiser Duguay- Trouin. Blockade duty at Taiwan was carried on by Rear Admiral Lespès’ squadron composed of La Galissonnière, Atalante, D’Estaing and Volta in the north as well as Villars and Champlain in the south.
Initially the French admiral thought that Admiral Wu’s squadron’s destination was Foochow, hence an order on February 6 for the ships to blockade the mouth of the Min River. On the same day, Courbet acquired additional information about the movements of the enemy squadron that revealed its commander’s passivity. In view of that intelligence, on February 7 the French commander seized the initiative and headed north. On the fourth day of the journey the French reached Chusan.
Since the enemy was not present in the harbour, Vice Admiral Courbet decided to turn back towards the mouth of the Yangtze River. His squadron reached his destination the next day (except Duguay-Trouin, which was running short of coal and had to be sent to Keelung) and dropped anchors at Gutzlaff Island. After contacting the local telegraph station, Courbet received new information concerning Admiral Wu’s squadron (his warships had been seen in Sanmoon Bay a day before) and on February 12 the squadron headed south. This time, the French admiral was almost certain to encounter the enemy. Therefore for the entire night the warships of his squadron were in a state of advanced combat readiness. Indeed, at dawn, on February 13, the cruiser Ėclaireur, steaming at the head of the French squadron, spotted five Chinese vessels on the horizon.
Admiral Wu spent the night of February 12/13 at anchor in Sanmoon Bay at Montagu Island. At about 05:00 his warships weighed anchor and steamed into the open seas, circling the island from the south at which point they were spotted by the French, who were approaching from the north. At that time the Chinese squadron was steaming in two line-ahead columns: K’ai Chi (flagship), Nan Shui and Nan Ch’en formed the starboard column, and Yu Yuan and Teng Ch’ing, the port.
Although Admiral Wu initially intended to accept battle, upon spotting the approaching enemy, he apparently suddenly changed his mind and ordered the slow Yu Yuan and Teng Ch’ing to turn back to nearby Sheipoo (Sheip’u). Wu then attempted to escape with the three remaining cruisers. It was 07:00 and both squadrons were no more than 10 NM apart.
After spotting the enemy, the entire French squadron began to chase the Chinese warships. Reaching 13 knots, the French warships were steaming in the following order: Bayard (flagship), Nielly, Ėclaireur and Triomphante (the last cruiser was initially behind the flagship, but was unable to maintain the speed of over 12 knots and gradually fell behind), while the slower Aspic and Saône finished the formation. Meanwhile, K’ai Chi, Nan Shui and Nan Ch’en, capable of reaching 14-15 knots, broke away from the two remaining Chinese warships and headed south-east, while Yu Yuan and Teng Ch’ing, following Wu’s orders, headed for Sheipoo.
Confronted with that situation, Vice Admiral Courbet ordered the slower Triomphante, Saône and Aspic to deal with the vessels fleeing towards Sheipoo, while he, along with Bayard, Nielly and Ėclaireur continued the pursuit of Admiral Wu’s cruisers. It soon became apparent that the French cruisers were not capable of catching the fleeing Chinese vessels. The situation was exacerbated when the weather soon broke and visibility was considerably reduced. Consequently, Vice Admiral Courbet abandoned the pursuit and, at about 13:00, joined his three remaining warships guarding Sheipoo.
The harbour of Sheipoo was located within a labyrinth of islands, islets and shallows. Four waterways leading to it were unknown to the French. For that reason, although the harbour was not guarded by any fortifications, Yu Yuan and Teng Ch’ing were relatively safe at Sheipoo, since Vice Admiral Courbet did not dare to venture with his warships into the treacherous, unknown waters. The only thing that he could do was to guard the entrances of the three waterways and that of the nearby Sanmoon Bay in case the Chinese ships attempted to slip away.
During the night and in the morning of the following day, three French steam launches covered by the gunboat Aspic, reconnoitred the waterways and located both Chinese warships anchored between Sheipoo and Tungnun Island. Since it was still dangerous for the French cruisers to close on the enemy, Vice Admiral Courbet decided to send in the steam launches armed with spar torpedoes.
Two launches from Bayard commanded respectively by Commander Palma Gourdon and Lieutenant Émile Duboc were designated for the action, each armed with one, 1878-pattern spar torpedo with a charge containing 12 kg of pyroxylin. The preparations had been completed by 22:00 and at 23:00 (February 14) both launches, guided by another two launches under the command of the hydrographer Lieutenant Ravel, set off for their mission. The night was very dark, which on the one hand favoured the attackers but also increased the danger of their launches grounding, getting separated or getting lost in the labyrinth of islands. Fortunately for the French, all the launches managed to avoid these dangers. Finally, at 03.00 both torpedo launches, struggling with the strong current, reached the inner roads of Sheipoo, where they began to search for the enemy warships.
As it turned out, finding the Chinese ships was not as easy as had been supposed. The French steam launches performing the reconnaissance of the waterways had been spotted during their sortie. Therefore, before 10:00 the previous day, Yu Yuan and Teng Ch’ing shifted their position and anchored closer to the town. After some time searching, the launch commanded by Gourdon was the first to locate the enemy, namely the Yu Yuan. The French launch managed to approach undetected within 200 metres of the enemy, and at 03:45 they extended the spar torpedo into its combat position and began their attack. They were at that moment spotted from the cruiser’s deck, but it was too late to open fire with the ship’s battery (particularly because the Chinese crews had not maintained full combat readiness) and the launch was instead chaotically fired on with small arms and mitrailleuses. This could not stop the French vessel, which successfully detonated her spar torpedo on the Yu Yuan’s starboard stern quarter and retreated, although not without suffering losses. One sailor was killed and the launch’s boiler was slightly damaged.
In the meantime, taking advantage of the ensuing confusion, the second French launch commanded by Duboc began her own attack. Practically unnoticed, she approached the Yu Yuan’s port side, but her spar torpedo failed to explode. It seems Lt. Duboc maintained his composure and since there was no time to once again detonate the torpedo at the Yu Yuan’s side (the launch had to keep moving and could not stop or go back), he apparently headed for Teng Ch’ing, anchored slightly further away, and repeated the attack. That time, the torpedo exploded at the side of the enemy vessel and Duboc’s launch retreated suffering no casualties.
Soon after the attack, both French launch es rendezvoused and together (Gourdon’s faster launch towed Duboc’s) set out for the rest of the French squadron. Their return journey was not without adventures – at about 05:00 Gourdon’s launch grounded, but was refloated with help from her consort. At 10:00, after steaming through the channel between the Islands of Kintan and Niumio (Niumiu), the launches reached the transport Saône. At the same time, Lt. Ravel was waiting for both launches’ return at the entrance north-west of Niumio Island. Only at dawn did he gave up further waiting and returned to the armoured cruiser Bayard.
On February 16 it was confirmed that both Chinese vessels had sunk. On hearing the news, the French warships weighed anchor and departed Sheipoo. Triomphante, Nielly and Saône headed for Keelung, while Bayard, Ėclaireur and Aspic steamed to Matsu.
As far as the crews of the Chinese warships were concerned, their losses during the attack were small and were apparently limited to only one man killed on board Yu Yuan8. Following the evacuation to the shore, the Chinese sea men set out for Shanghai. After four days they reached Chenhai, where they encountered the remainder of Admiral Wu’s squadron which had been reinforced with the small cruisers Chao Wu and Yuan K’ai as well as the gunboats Lung Hsing and Hu Wei. Since the French blockaded Chenhai soon thereafter, the Chinese squadron remained trapped until the end of the war.