I usually put one 6-7' trunk vertically (3" pvc) with two 1.5" lengths running at a 45 angle and fill the bucket with 40lbs of concrete. I also add some 1.5" pieces (4 or 5) that stick just above the top of the bucket. All these that are in concrete, I drill a 1" hole on the end so the concrete can fill and get a hold on the pipe. Then I put 3/4" or 1/2" PEX in 5' lengths on the vertical pieces to make branches and then rough sand all the pieces. Then I stick cedar or bamboo in the short tubes and anchor with a couple of screws and wire. This way I can build a bunch at one time and add the foliage when I want to put a few out.
Here are ones with Cedar.
Here are ones with Bamboo.
If it is a Corp. of Engineer lake, you could get a ticket for dumping them in the water. I tend to wake about 2:00 in the morning so I have never verified if the Corp frowns at this activity.
LiftSaver Trolling Motor Mounting Bracket - Patent Pendingwww.liftsavertmmount.com
Works with MG Xi5, Xi3 and MK Terrova, Ulterra, PD V2 and Riptides as well.