Tie Down Floating Post Style Trailer Guide-Ons The Tie Down Floating Boat Trailer Guide-Ons makes loading and unloading your boat trailer easy. These floating posts feature the ability to adjust the overall height from 48 to 60 inches. This post can be notched at a specific height or can be set on floatable mode. In floatable mode, the waterline will naturally and automatically adjust the overall height as the post enters and exits the water. This allows the post to always remain above the water