Boat lifts can either be installed on the dock, or on ships and boats. The dock ground is strong enough to hold the boat lift securely. When lifting objects, they will not fall off the ground.
Even boats whose floor is usually made up of wood require boat lifts to be installed very strongly. They must also be checked and tightened using strong nuts and bolts.
The biggest reason why people use boat lifts is that they have undersized boats or if there is a storm rolling in. This will protect the boat from banging against the side of the dock as the water picks up energy.
Boats that can be lifted out of the water will be protected from damage from the water's energy. Also, they will not be subjected to the rot which can occur when a boat is in the water too long. This is why most boathouses will have the right kinds of lifts to keep high and dry.
These lifts are not used for heavy lifting purposes and will only manage to lift normal boats. You may find these lifts which are operated manually or are operated on electricity. The manual ones are cheaper than the electrical ones as they can operate manually and you have to load and unload the boat in and out of the water yourself.
Finding the right lift will help you to protect your boat as well as keep your boat safe while you are using the lift.