In the Florida Keys the cradle boat lift is sometimes called a 4-post boat lift. There are several types of boat lifts available on the market today and they all have their advantages as well as disadvantages. A cradle lift is a boat lift that is mounted on top of 4 pilings. These pilings are normally wood or concrete and are driven into the bottom.
The cradle lift is the lift that I would recommend to the person that has the space for it. In Islamorada, Key Largo, and Marathon this is a common lift due to the fact that when the boat is on the lift and lifted out of the water there is no aluminum immersed in the water as can be seen in the photo above. This will prolong the life of the boatlift in our salt-water environment where electrolysis is a huge concern as compared to an elevator lift where there is always aluminum immersed in the saltwater. As you can see in the photo below the aluminum I-beams are in constant contact with the water.
The disadvantage of a 4-post cradle boat lift is accessibility, because there are 4 pilings that you must pull your boat between. You must have the space to maneuver and navigate between the pilings upon entering the lift. The 4-post lift is recommended for docks that do not have limited space due to neighbors or other boats.
As you can see in this photo you can pull straight into the lift.