Building a floating duck raft/platform..?

[iluvsedward]

I want to build a floating duck raft out of logs (I have plenty because of a big storm recently) I'm thinking 4x4, 4x5, or 5x5 would be a good size range.. and then somehow rope them together and put a piece of plywood on top and then attach a dog igloo in the middle (nesting and protection from hawks) and then anchored with a cinder-block. I think it will sit low enough in the water that they can get on it.. I currently have 4 ducks, does anybody have any advice/tips?

 

[Stealth Squabs]

I am way late to post on this, but I have the same idea using capped PVC tubes for pontoons. I have a duck house and Muscovies who don't feel they need to follow rules. I have fox coyote and mink for predators, and until the pond freezes, I am trying to keep the miscreants safe.