6 foot by 8 foot homemade barrel raft

Hello to everyone. Me and my friends are currently building a barrel raft. It seems to be a popular design from what i gather online. We're using 4 plastic 55 gallon drums to keep afloat. To keep the barrels in place we're using 1inx4inx8ft slats of pressure treated lumber. The flooring will be 2 sheets of 3/4th inch 4ft by 8ft plywood. The catch is that we're cutting them into 2 3ft by 8ft pieces and attaching them together to make a 6ft by 8ft flooring. We're also throwing in some galvanized steel wire to keep the barrels from slipping out. According to stuff I've looked up it our sink weight is 1,800lbs (4drums x 55gal x 8.3lbs). Our 4 person combined weight is 700lbs, 50 lbs in supplies, 100lbs for the 4 drums, I'm hoping 300-350lbs for all the lumber+plywood. Total: 1,200lbs?

Attaching a sketch.
brown is the 1in x 4in x 8ft pressure treated lumber
background is the plywood
the dotted line is the connection of the 2 3ft by 8ft pieces
green is the galvanized steel wire
blue is the barrels

Thanks for reading. Just wondering... will it float!? Also can we sail it in the Chicago River? or in Lake Michigan? Is it allowed? None of us have a boating license and it won't be registered. Thanks!!!

http://img294.imageshack.us/img294/8202/raftsketchmh9.jpg

 

Bad design. At maximum load your hulls (barrels) should be submerged no more than about 1/3 their depth -- or at the very most 1/2. You're way beyond this with only 4 barrels, so you need more.