It consists of a structural platform that is lifted and lowered exactly vertically, synchronously by a number of hoists.Many shiplifts use a transfer system for ships so that the vessels can be transported from the water to a parking place where they can be painted or repaired.For large vessels the transfer system consists of a number of trolleys or cradles, supported by high capacity steel wheels.The cylinders are also used to lower the ships on a static support, so that the transfer system with the active elements can be recovered.Smaller devices called "Boat lifts" are available that simply raise yachts, sailboats, or small watercraft above the water level at a dock for storage, for reduced maintenance cost and increased security.
