In ancient times, how ships in the sea were oriented

By the sun during the day and by the constellations at night, plus a compass.

Compass, and the captain's knowledge of the astrology.

A few days ago, this reporter saw in Dongfang City, Hainan Province, that Jiulong Square, which covers an area of more than 640 acres and was once regarded as an image project by the masses, has become a nursery base for returning farmland to forest. This is a microcosm of Hainan's construction of an ecological province. Since the beginning of this year, Hainan Province has signed three major ecological responsibility certificates with cities, counties and key enterprises of "coastal defense forest construction", "energy conservation and emission reduction" and "protection of cultivated land", and comprehensively launched the action of guarding mountains, protecting rivers and protecting the sea, and comprehensively promoting Hainan's ecological construction.

Hainan is known as the "Garden of Four Seasons". However, in the past 10 years, the ecological environment has changed worrisomely: coastal defense forests have been severely damaged, millions of acres of wetlands have been desertified, the perennial flow and storage of rivers and reservoirs have decreased, and the area of sea pollution has reached square kilometers.

The excellent ecological environment is an important foundation for Hainan's sustainable development. At no time and under no circumstances can a temporary economic boom be exchanged for the environment. In May this year, Wei Liucheng, secretary of the Hainan Provincial Party Committee, proposed at the provincial party congress to take "ecological province" as the strategic fulcrum of Hainan's scientific development and comprehensively promote Hainan's ecological construction.

Hainan has started to promote ecological construction from "mountain protection". This year, Hainan will compensate 3.9 million mu of forests that are not included in the natural forest reserve in the province at the rate of 5 yuan per mu per year. At the same time, the construction of civilized ecological villages has been promoted, and more than 6,900 civilized ecological villages have been built, accounting for the total number of natural villages in the province.

More than 200,000 rural households in mountainous areas have been supported to build biogas digesters, so that 1.4 million acres of natural rainforest in the province are protected every year. Wuzhishan City has invested more than 100 million yuan in five years for ecological protection. Baoting Li and Miao Autonomous County, Tunchang County, and Qiongzhong Li and Miao Autonomous County, which are located in the mountainous area of Wuzhishan, have closely combined the construction of small towns with ecological migration, and relocated more than 5,000 farmers who have lived in deep mountain forest areas to small towns, implemented the closure of migrants, and effectively protected the ecology of Wuzhishan.

Nandu River, Changhua River, Wanquan River and Wenchang River are the four main rivers in Hainan, which are important water sources for drinking water for 8 million people in the province and irrigation of more than 6 million mu of cultivated land. Since 2006, Hainan Province has dispatched thousands of law enforcement personnel to conduct comprehensive inspections of 1,653 polluting enterprises in the province. This year, the province and 18 cities and counties and 11 key energy-consuming enterprises in the province signed a target responsibility letter to rectify projects with high energy consumption, high pollution and serious ecological damage within a time limit.

According to recent information provided by the Hainan Provincial Department of Oceans and Fisheries, in recent years, the water quality of the waters adjacent to the estuaries of the four major rivers has all met or exceeded the national Class I water quality standards.

In the past two years, Hainan has gradually improved the supporting system of laws and regulations for the protection of the sea, and intensified the construction of coastal defense forests. At present, Hainan has established 6 nature reserves with mangrove wetlands as the main protection objects, and the existing 3,930 hectares of mangrove forests in the province have been effectively protected.

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Related:

Dreaming of a boat in a rough sea: The boat journey symbolizes the voyage of life. Hardships and dangers mean that the road of life is full of thorns, or it represents the challenges and crises of life.

Smooth elimination: It means that there is no danger, and any difficulties can be overcome, and it also indicates that the future life path will become stable and smooth. It's a good dream. Good luck!

(1) F float = g row = m row g = 10000 103kg (2) The ship floats, the dead weight remains the same, the buoyancy of the ship remains the same, the sea water river water, by the F float = liquid v discharge g get:

The volume of the discharged seawater is smaller than the volume of the drained river, and it will sink a little Therefore, the answer is: Sinking

Riding the Wind and Waves: [Basic Explanation]: The ship rides the wind and waves to move forward. The metaphor overcomes difficulties and forges ahead.

Pinyin pronunciation]: chéng fēng pò làng [use example]: The ship is in , and the car is driving through the field. (Mao Dun's "Midnight" 5) [synonym group]: overcoming obstacles and marching forward.

Antonym phrase]: hesitant and depressed.

How to use]: Linked; as a predicate; With praise, describing the rapid development of the career [idiom source]: "Song Shu Zongfu Biography": "When he was young, Bing asked his ambition and said: 'I am willing to ride the long wind and break the waves of thousands of miles.'" ’”

After the break]: Sailing in the sea.

The career is smooth sailing, brother, take me with you.

In the Yangtze River: According to Archimedes' principle, the buoyancy is equal to the gravitational force of 50,000,000 Newtons of the water discharged.

In the sea: floating, buoyancy equal to gravity, 50000000 Newtons.

In this process: because the density of seawater is greater than that of river water, the discharge decreases and it floats.

Buoyancy is equal to the mass of the ship, the mass of the ship decreases, the buoyancy decreases, the waterline decreases, the pressure = pgh, and the pressure decreases when h decreases.

Buoyancy becomes less and the pressure becomes smaller.

The speed of the boat in a river is equal to the speed of the boat v plus the speed of the current.

The algebraic expression is: v+3

When the speed of the ship in still water is v km, the speed of the ship is (v+3) km, and the speed of the reverse water is (v-3) km.

If the speed of the boat in still water is v kilometers per hour, then the speed of the boat in the river is (v+3) kilometers per hour and the speed of the boat against the water is (v-3) kilometers per hour.

If the power speed of the ship is V, then when going up, the speed of the ship is V-3; When descending, the speed of the boat is V+3.

The speed of the uplink is: V+3

The speed of the downlink is: v -3

Happy New Year's Day!

Downstream: v = v boat + v water.

Countercurrent: v = v boat - v water.

Hope it helps!

Take the water directly as the reference system, or the original velocity, and try to do it later.