B'ski I have seen 2 types. I am sure there are many more. One is a chain link fence type. It has posts about 3 ft on either side of the pier with the gate attached to one and connecting to the other. Gate is about 10in above the pier height. It locks to the second post. It was about 6 ft high. The reason for this approach was to be able to see through the gate to the lake/pier end. The second was similar but was wood and matched the pier. The gate opened in the middle to swing to each post. Locked in the middle.