My mistake is about 10x10 and only serves as an occasional fishing platform.
Not only do the bungs seem to finally crack and leak but people seem to prefer sitting at a table or in a smaller, more face to face grouping. And, unless they are fishing or swimming, adults will pick a shady spot every time. On the other hand, children... well, no sane person would try to predict what boys will do, but it'll probably be somewhere between totally unacceptable and just plain dumb. Girls seem to be much less adventurous.
The good thing about my dock is it is off the edge of a hill and has shade every evening for about 2 hours. Furthermore, it is 50 feet from my back porch and outdoor kitchen. I anticipate a LOT of time out on the dock. It will also serve as a swimming platform as the banks are very steep and the boys LOVE to jump off of it.
