Abstract: A boat lift includes a vertical main post mounted on a dock, the lower end of the main post inserted into a body of water adjacent the dock and with the lower end spaced above the floor of the water. A frame includes an outer guide post having a base mounted on the water floor with an upper end above the water level; the frame connected by a single member to the main post. A platform unit for supporting a small boat is slidably connected at both ends to the main post and the guide post, and a cable and winch unit is interconnected among the foregoing elements for effecting a level lifting and lowering of the platform unit into and out of the water.