Floating Docks
Floating docks are used at many waterfront homes as a means of securing and gaining easy access to the owners boat. Docks are usually constructed from pressure treated wood with buoyancy provided with Styrofoam. The most common material is Pressure Treated lumber that has been pressure-impregnated with a preservative which makes the wood resistant to attack by termites, fungi and marine organisms that can cause decay. Some designs utilize the new trex plastic wood planks for decking. Compared to conventional decking lumber, Trex decking offers outstanding durability without preservatives or sealants, Trex also offers an elegant natural coloring that stays looking great year after year. When using Trex be sure to add additional support because these planks are more flexible than conventional wood planks.

 
When mounting a floating dock to a bulkhead you can use pipe or a bar that is U shaped. The pipe can be mounted to the top of each piling rise upward then outward and then straight down into the sea bed.
 

Floating dock should be secured to a bulkhead or pilings with proper marine hardware. Make sure you consider maximum high tide and use hardware that permits the dock to float well above the high tide mark without breaking free. When mounting a floating dock to a bulkhead you can use pipe or a bar that is U shaped. The pipe can be mounted to the top of each piling rise upward then outward and then straight down into the sea bed. Depending on the bottom composition the pipe could be screwed into the bulkhead at its base or the pipe could just be left long and jetted into the seabed. Jetting may should difficult but its actually pretty easy. Just adapt a garden hose onto the top end of the pipe and turn on the water. The pipe will dig itself into the seabed. On the Floating dock mounting rings are securely bolted in place. The bulkhead mounted pipe runs through these rings. Basically the floating dock can then slide up and down the pipe with fluctuations in tide level while still being held in place and not floating away.

 
Floating dock on left is secured to pilings with chain. The chain is paced through small segments of pvc pipe in an effort to prevent it from getting caught on the piling as the tide goes up and down.  floating dock on right utilized marine hardware U bar which hold the dock nice and secure without the disadvantage of snagging onto the piling with tidal movement.

Floating docks can also be secured in place to pilings. Usually a chain is secured to the dock that wraps around the piling. Chains work fairly well but I have seen a couple that get caught on the piling. The result is that the floating dock get pulled under as the tide rises. Using a u bar to wrap around the piling will solve this problem.