A semi-submersible vessel or deck carrier is mainly used in marine projects to carry large structures like production platforms, other floating vessels, or heavy cargo. Basically, it is supported by pontoons underwater, with steel columns on top of the pontoons providing support for the vessel. The pontoons can be filled with water (ballasted) to help the ship sink or float easily. If the vessel needs to move from deep water to shallower areas, it can remove water from the ballast tanks to adjust its height. Once the cargo is loaded onto the deck, the vessel can raise itself out of the water and carry the cargo to the destination. Thanks to this technology, many marine operations can be done smoothly and efficiently. This makes semi-submersible vessels very important for offshore and marine work.