There is a launch ramp at the Top Water Grill in San Leon, TX (29.471771266983346, -94.92593759466979). It is steep and a bit narrow but Connie and I launched the 21 footer there several times. Day sailed the bay, come back, tie off to the dock and go get a meal and a drink before retrieving the boat. ;D
Eagle Point Fishing Camp northeast of Top Water Grill has a ramp, also. We launched there ONE time. The end of the ramp was too shallow for Unole and we had to wait for high tide to get the extra depth to retrieve the boat. Your mileage may vary. But we needed nearly 4 feet of water due to the supports of the trailer.