The first type: open the Maritime Safety Administration of the People's Republic of China and Shanghai Maritime Safety Administration on the computer, which contains navigation warning materials, which are divided into navigation notices and navigation warning columns. You can query in the navigation early warning section as needed.
The second type: mobile apps with maritime navigation warnings are available everywhere, mainly involving Shanghai, Tianjin, Liaoning, Hebei, Shandong, Zhejiang, Fujian, Guangdong, Guangxi, Hainan, Yangtze River, Heilongjiang, Shenzhen and Lianyungang. You can download the APP through your mobile phone and check the navigation warning after logging in.
The third type: call the local provincial and municipal maritime bureaus to ask for navigation warning data during working hours.