You don't say where you expect to build it - Maybe.

Dan Listermann wrote:
I want to build two docks, one permanent and a floating one. The floating
one will be supported by 15 gallon plastic drums. I can get 55 gallon, but
for a 4 x 8 dock, I worry about center of gravity issues.

The permanent one will be built of 55 gallon drums filled with dirt. Any
issues to look out for?