5' Bunkboard Boat Guide-Ons Carpeted bunkboards provide proper center loading even in wind or side current conditions. 2'' x 4'' X 5' boards tilt to hug the hull and are covered with high grade marine carpet. Distance between Fore and Aft galvanized upright posts can be adjusted to fit trailer. Height of 21'' with adjustment out to 13" from frame on each side. Can be mounted on top of frame for extra height. Complete with mounting hardware to fit frames up to 3'' wide x 4-1/4'' high.