Looking for some help here --
We've just placed a 12' x 8' pontoon raft in about 9' of water. We used 2 250lb cement blocks each with its own SS chain on two sides of the raft. It's still floating away! In about two hours, it drifted ten feet.

There was no slack in the chain - but we still have 3-4' of chain to spare on each side. In the area where it is, we get a lot of waves (boat wake) and we're thinking it's causing it to lift and move??
What can we do to keep it in place? Do we need more weight? Should we consider using snubbers? (I know what they are but need some advice as to how to use them in this case.)
Thanks in advance for your help and advice!