A Conolift sling lift trailer offers users the ability to easily launch, retrieve, and store both powerboats and sailboats on a launch ramp. The sling system simplifies lifting boats, and unlike a conventional trailer, a sling lift can place boats either into cradles or on stands. For facilities with a launch ramp, a sling lift offers the ease of use of a straddle carrier, while avoiding the need for a costly lift well. Sling lifts offer lift in both the posts and the wheels, and are adjustable in width to minimize the wasted storage space inherent in a fixed-width lift.