Abstract: A boat trailer in which a boat is supported on a carriage, which in turn is roller supported on a wheeled chassis and is extended from the chassis to launch or recover the boat without the trailer wheels entering the water. The trailer wheels are mounted at a fixed position on the chassis and the primary carriage supporting rollers are directly over the trailer wheels, so that the load is concentrated at the trailer wheels during loading and unloading and tipping loads on the trailer and towing vehicle are minimized. A ground engaging roller supports the rear end of the carriage when extended, the forward end of the carriage having a ramp which allows the carriage to be lowered close to and parallel to the ground when fully extended. Adjustment is provided for the bow snubbing post and for the loaded position of the carriage, which allows the trailer to accommodate boats in a wide range of sizes with the load substantially balanced over the trailer wheels.