Abstract: An accessory to be removably or fixedly attached to a boat trailer and including a support assembly having a casing means attached to the frame of the boat trailer. A cradle frame is disposed and configured to be slidably mounted within the casing of the support assembly and be positioned for longitudinal movement relative to the longitudinal axis of the boat trailer by activation of a positioning means including a winch and interconnected cable structure. Dimension and configuration as well as disposition of the cradle is such as to force it to extend outwardly from the rear of the boat trailer on which it is mounted for the purpose of delivering a boat to the surface of the water and/or retrieving it therefrom without getting the wheels or like running gear of the trailer submerged within the water itself.