What do you mean, have two feet on both sides?

Metaphor is to look at both sides and want to take advantage of both sides.

Trade two boats.

A popular saying is to look at both sides and want to take advantage of both sides. You can't let go of the five acres of wheat by the river. Who hasn't stepped on two boats in the first year? (Liu Shaotang's "Green Branches and Leaves")

Knowledge expansion:

A ship or boat refers to a vehicle that uses the buoyancy of water and relies on the power of manpower, sails and engines (such as steam engines, gas turbines, diesel engines and nuclear power plants) to pull, pull, push, paddle or push propellers and high-pressure nozzles to move on the water.

In addition, civilian ships are usually called boats (junk in ancient times), ships, airplanes and boats, military ships are called ships (junk in ancient times) and warships, and small ships are called boats, junk, rafts or boats, collectively referred to as ships or boats.

Ships are developed with the development of human beings. Whether in wartime or in peacetime, there are ships. Millions of fishermen around the world use fishing boats to catch fish. Wartime naval warfare and maritime munitions are all related to ships.

In 2007, there were about 35,000 merchant ships carrying 7.4 million tons of cargo. By 20 1 1 year, about 104304 ships in the world have obtained IMO numbers.

In the era of great navigation, a ship was defined as a sailboat with at least three masts and a complete bowsprit, and masts were also used to define other types of ships, such as three-masted sailboats and cross-sail masts.

When a ship sails in water, its leading edge will be resisted by water, which can be divided into many components, mainly the resistance of water acting on the hull and wave resistance. If the resistance decreases, the speed will naturally increase, and it is necessary to reduce the wetted surface. The hull without water should also be changed into a shape with smaller amplitude of water waves.

In order to achieve this goal, high-speed ships are generally slender and have little or no attachments. If the parasitic organisms and algae on the hull are cleaned regularly, the resistance of the ship can also be reduced, and the antifouling paint can also reduce the organisms on the hull. Advanced design such as spherical bow can also reduce wave resistance.