A winch post is an accessory that can be added to or come stock with a boat trailer. Such trailers are used to haul boats over land by attaching to a towing vehicle such as a pickup truck. In order to get the boat onto the trailer, a winch is usually used to haul it forward. This winch is mounted to a winch post, which is essentially a bar that is secured to the front of the trailer. This bar is usually set at an angle away from the boat itself to provide a strong contact point for the winch system.
The device used to haul the boat onto the trailer features a drum around which a cable is wound numerous times. The drum is mounted to a frame by an axle, and the axle is attached to a handle that can be turned by hand to either feed out the cable or retract it as necessary. Some winches feature a motor instead of a handle to power the system. The entire winch system is secured to a winch post for a few reasons. First, the winch post keeps the winch itself off the frame of the trailer so the weight of the boat and winch does not compromise the strength of the trailer frame; second, the post raises the winch higher than it otherwise would be mounted, which makes hauling boats with larger hulls possible.
Various sizes of trailers and boats will require a different size of winch post. Larger boats will require a post that raises the winch higher up off the frame of the trailer. The end of the cable of the winch system features a hook that will connect with a receiver of some sort on the hull of the boat, so the higher the bar is, the more cable can be retracted, thereby pulling the boat as far forward as possible. Some smaller boats will only need a small winch post, or they may not need a post at all. The winch may be mounted directly to the trailer in some instances.
Sometimes other accessories can be mounted to the winch post as well. One of the most common accessories mounted to the post is the spare tire for the trailer. This keeps the tire out of the way and prevents it from taking up usable space anywhere else on the trailer. The tire will not interfere with the function of the winch either.