Floating cranes are large pieces of machinery that can stand on a platform in the water. They are used in bridge construction and for construction and dredging required in ports and harbors. Sometimes, they are used to load or unload large vessels that cannot tie up to a wharf or for heavy and awkward loads. Some floating cranes are mounted on a pontoon, which is a flat-bottomed structure made from fabricated materials. The pontoon can support the heavy weight of the crane because it floats on the water like a raft.
Some floating cranes are capable of lifting extremely heavy loads, such as sections of bridges that can weight as much as 10,000 tons. In the case of salvage work, this type of crane is used to bring sunken ships to the surface.
A floating crane can pick up a heavy load and deposit it in another location with pinpoint precision. It has a capacity for sensitive thrust control in longitudinal positions and transverse directions that make it very accurate. Wind and water currents do not affect the operation of this machinery. One of the propellers of the crane is attached to the structure, which could even be a large ship, and the other is attached to the bow. The front and rear winches are powered by hydraulics and the independent hydraulic circuits allow the lines to pull on front and rear drums. Heavy work can be done much faster in this manner.
An operator of a floating crane manually handles the vertical lift controls as well as the boom hoist by manipulating a single sway lever. This lever prevents the load from swaying while it is in the air. The lever puffing control is an automatic one that prevents the crane from pitching or rolling in the water. This control could be either on the crane itself or handled from shore.