I use these on the posts at my home dock:
https://www.westmarine.com/buy/taylo...04?recordNum=3
They mount on the vertical posts.
Parafunalia also has them, so support our local vendors.
If you prefer, they make a version that is very temporary:
https://www.westmarine.com/buy/taylo...05_157_006_005
They last for years! They can be removed and reused if you rent a slip. They can be easily cleaned.
Place them so your rub rail will hit them at both high and low lake levels and you are good to go! See the photo to see how I install them.
I try not to use fenders as they will scuff and scratch the fiberglass! It took me a couple of years to learn about this.
Now I only use fenders when:
1: Boat to boat, such as when rafting
2: I'm at a dock where my rub rail won't match up to the posts, even if the posts are bare wood.
Some use polyester fender covers to try to stop the scuff and scratches caused by fenders, I try to minimize fender use as much as possible:
https://www.westmarine.com/buy/west-...rs--P017216367
Or you can make your own covers cut from the legs of cheap polyester sweat pants purchased at Wal-Mart.
With a black hull the scuff and scratches from the use of fenders is very apparent. If you have a white hull, it's not as easy to see, but it is still occurring.