This 12 inch Hot-Dipped Galvanized Swivel Top Bunk Bracket kit is designed for boat trailer bunk board set ups that commonly use (2)- 6 Foot Boat Trailer Bunk Board Runner Pre-Carpeted 2 in x 4 in sets and also to adjust the angle to the contour of the boat hull. Typically, these adjustable swivel bunk board brackets are mounted to cross members in front and behind the axle, a common single axle trailer might have (4) of these. These galvanized 12 inch Bunk Brackets have slotted 1/2 inch diameter holes to accommodate 1/2 inch Boat Trailer Bolts or Boat Trailer U-Bolts. The slotted holes allow you to adjust the height of the bunks. Keep in mind when replacing the entire Swivel Top Bunk Bracket you commonly will also need new mounting Bolts or U-Bolts, and also we be needing replacement 5/16 x 1 1/2 Galvanized Lag Screws for Swivel Top Bunk Bracket (2) to re-mount your bunk boards if you are using a 2 x 4 or 2 x 6. There is an image that shows a Model of a Swivel Top Bunk Bracket attached to a 3 by 3 Cross-Member using a U-Bolt (This Does not represent how every swivel top is mounted, but just shows an example.) These Swivel Top Bunk Brackets are also commonly mounted to cross members that are C Channel in shape and have different dimensions. Measure your frame dimensions, or simply measure your previous U-Bolts if you are replacing with the same setup!
This Style of bunk support is also sometimes used towards the front of the trailer on the front two cross beams. You would use what is referred to as mini bunks to support and guide the bow of your boat towards your winch post.
This kit includes the support bracket, swivel top, 7/16" x 1" zinc plated bolt for mounting the swivel top to the bracket, and the bolt hardware.