My nephew & I built a small floating dock (8 x 8) a couple of years ago with barrels. It is way too small. I'm a pretty big guy and I can stand on one edge and tilt it enough to think getting wet is very possible. With another person we are both going for a swim.
My plan is to build a fix dock about 21 feet long and then attach the floating dock to the end.
Zep, I'm delighted to hear that your pond is full. I'm hoping after the rain from the past couple of days that we are getting full. It will be the first time in 2.5 years.