alrighty lets see here, you are correct on the plank. Three for the box and the rest 1"x6"x3ft deck boards. The dock will have the 4 for the box. Then I am thinking 8 down the middle. each drum is 23x35 inches. So if I put 3 down the right side, and 3 down the left I have 2 boards butting those up to the sides at 24" apart. Then in the middle of the dock 2 more boards 24" apart for any drums I have to put down the middle. that leaves me with about 72 inches. At 16" spacing roughly 4.5 boards. So basically I will try and put 2 more on the left and 2 more on the right. So what did we end up with (adding)...so I think we have about 12 2x6x12's for the deck. and by the way, thanks for helping me with this.