As for the remaining more than one million taels of silver, Liuqiu Company invested all of them in the construction of the navy. It is not an exaggeration to say that building a strong navy is a matter of life and death. As a technical branch of the armed forces that rely heavily on equipment, it is not an exaggeration to say that the navy is a gold-eating beast. The sea is stormy, the structure of the ships used is complex, the technical requirements are high, and the price is naturally expensive. For Liuqiu, the naval vessels to be built must be mainly equipped with firearms. Firearms are powerful, but the price is naturally expensive, take the main battle equipment artillery of the warship as an example, not only the cost is expensive, but its subsequent maintenance and ammunition consumption is also a huge expense.

It's just that no matter how expensive the construction of the navy is, it will cost money. In addition to protecting the island, the navy also has the important task of protecting trade routes and opening up overseas. The former is the key to the development of flow, and the latter is what Ouyang Xuan particularly emphasized. From the perspective of actual demand, in the surrounding sea areas of the current Liuqiu, the naval force of the Southern Song Dynasty Coastal Control Division is very strong, although the relationship between the two sides is acceptable at the moment, and even provides escort for the Liuqiu ships that transport displaced people and goods. However, "the husband is not guilty, but he is guilty", and Liuqiu is now developing thrivingly, and sugar alone is a huge income, not to mention a large number of fertile land mines, which is really a huge temptation for the extremely embarrassed imperial court finances. With the virtue of those corrupt high-ranking officials in the DPRK and China, once the political situation changes or their "filial piety" is broken, they will definitely turn their faces faster than turning over books, and if they wake up that day, they will let the officials and navy attack Liuqiu in order to gain the fame of opening up the territory and expanding the territory.

The second threat comes from maritime merchants such as Pu Shou Geng. As the saying goes, "peers are enemies", the Thunderbolts will inevitably squeeze out their monopoly share of maritime trade, and they will obviously not tolerate a share of the lucrative maritime trade. Pu Shougeng and others are now also trying to plant sugarcane on Fujian Road and Guangnan Road, and there will inevitably be conflicts in the future to compete for the sales market, and it is not even ruled out that they will use force to seize Liuqiu. This maritime merchant is powerful, Pu Shougeng alone has tens of thousands of horses and thousands of ships, and he is also an official appointed by the imperial court as the director of Quanzhou City. These are only the superficial strengths of Pu Shou Geng, in fact, Pu Shou Geng and other sea merchants are not only bound to the interests of the court bosses, but also inextricably linked with pirates.

The naval armies of Goryeo, Wa and the northern Han army did not have the strength to attack Liuqiu at the moment, but because of the weakness of the naval armies in these three places, their coastal periphery was full of pirates of all sizes. Many of these pirates were vicious outlaws, many were coastal people who were forced to take risks to make a living, and there were also a few opportunists who mainly fished and engaged in business, and robbed at sea to make a living at every opportunity. Most of these pirates had previously been found near trade routes, and had not been seen in the vicinity of Liuqiu. With the development of the Thunderbolt Army's pioneering career, Liuqiu became more and more prosperous, and these pirates were like sharks smelling blood, frequently attacking Liuqiu's fishing ships and merchant ships, and even tried to sneak attack the sugar warehouse in Taichung City Port, but without exception, the artillery was beaten. Liao Loach, who was in charge of military affairs, was not worried about these stragglers, but worried about the shadowy forces behind them.

More than one million taels of silver seems to be a huge amount, but it is actually not much for naval construction. Liao Loach had previously proposed to expand the navy to 20,000 people, and the number of large and small artillery warships should reach 200, but the cost account was not calculated. In fact, no matter whether it is purchased or self-built, the warship itself is not expensive, the medium-sized warship is only a few thousand taels of silver, the large warship is only worth more than 10,000 taels, and the largest triple-building ship will not exceed 50,000 taels of silver. What was really expensive was the artillery on the battleship. Take a medium-sized warship equipped with 20 guns as an example, a cannon will require 300 catties of copper worth 30 taels of silver, and the manufacturing cost will be about three times that of copper, so a cannon plus the necessary ammunition will cost 150 taels of silver, and 20 guns will cost 3,000 taels, plus the hull cost 2,000 taels, and a medium artillery warship will cost 5,000 taels of silver. Because large ships used larger and more guns, they cost three to four times as much as medium guns. In fact, this is due to the fact that there are abundant copper mines on the island, and there is no shortage of high-quality wood and iron, and if the materials are purchased, the cost will increase several times.

After repeated calculations, Liuqiu Company decided to set up a main fleet and two sub-fleets, which were stationed in Taipei, Tainan and Xiaoliuqiu. The main fleet consisted of ten large ships, twenty medium ships, and forty small ships, and the number of ships in the sub-fleet was halved. 15,000 taels of silver for one large warship, and 300,000 silver for twenty ships; 5,000 taels of medium-sized warships, 60 of which amounted to 300,000 silver; There were 2,000 taels of small warships, 120 of which amounted to 240,000 taels of silver, and the main warships alone cost 840,000 taels. If we add fire warships, reconnaissance ships, blasting ships, transport ships and other ships, this million taels of silver is not only not much, but it seems to be slightly insufficient. In terms of numbers, each large battleship had one hundred and fifty men, eighty medium ships, and thirty small ships, bringing the total strength to ten thousand two hundred, and if the number of sailors of the auxiliary ships was added, the strength amounted to twelve thousand.

At present, the current naval strength is only a quarter of the above-mentioned scale, and although there is a financial guarantee, it is by no means easy to build a navy of tens of thousands of people, and it will still take a long time to achieve. The construction of the naval fleet requires three major elements: "ships, crews, and artillery." Unlike the main shortage of artillery in the expansion of the Thunderbolt Army in western Sichuan, the most lacking thing in the Liuqiu Navy at the moment is not artillery, but warships and experienced sailors. The technicians brought by Yu Zhu from western Sichuan had already mastered the manufacturing technology of copper cannons, and after the copper ore was mined, they adjusted the ratio and optimized the production process according to the local copper material. Due to the excellent ductility and thermal conductivity of copper, the production of artillery only needs to use a simple casting method, and does not need the boring and milling process used by the iron cannon of the Thunderbolt Army in western Sichuan, and the copper cannon produced is not only light in weight but also sufficient in performance, and more importantly, the man-hours spent are much shorter. At present, there is enough copper to be studied, and only after refining, a large number of naval guns can be produced.

The main combat weapon of the Navy is the ship, and the construction of the ship does not happen overnight. From material selection, logging, drying, construction, outfitting and sea trials, a warship can be as short as one to two years and as long as three to four years. If there is wood that has been dried, it will take half a year to a year to make it. Liuqiu, whether it is the current practical needs or long-term threats, cannot afford to wait for such a long time, so Yu Zhu decided to send people to buy shipbuilding wood on the one hand, increase the efforts of self-shipbuilding, and at the same time send people to buy ships for refit with a lot of money, and even buy the warships of the coastal control division through bribery. "There must be brave men under the heavy reward", as long as the price is high enough, those officials of the navy dare to sell the warship at the risk of killing their heads. After these purchased warships were refitted in the dockyard, no one would recognize them as official warships. After some efforts, Liuqiu purchased and modified more than 10 large and medium-sized ships and dozens of small boats, although it still did not meet Liao Loach's expectations, but also solved the urgent needs of the moment.