I screw/nail them together and used cable ties and or trot line cord. They are hard to sink (not sure 4 blocks will work. If you set them in shallow water for a month then drag them out for final placement it is easier.
4 blocks sank this one with ease, the wood was dry as a bone. If you used 4 pallets that might be differant, But 4 blocks sank three pallets no problem. I placed three of them that day....
the key for me was they still were easy to move in the water because of the dry wood but would sink when realeased. Now they have been under water couple years i might need a crane to move them unless I cut the blocks free.
