@capseaquel sounds like you are doing some upgrading on your Hunter.
The lifeline gets terminated on either side of the gate. Since your going to be putting some stress on the lifelines you cannot just leave a single pole stanchion at the gate. It needs to be braced. Here is what a sample gate stantion looks like.
There are several variations to this basic design. I found mine from RailMakers of Everett WA. Mine use through bolts to attach the stanchion to the deck. The gate is between the 2 long vertical posts. The side posts act to brace the main post from bending.
You can use a pelican hook to latch the gate. The material can be wire, or as I did dyneema.
Take a look around your marina to see the various designs, then choose one that meets your needs.
Good luck.