What are the pertinent code requirements for running power on a dock for a boat lift for a 30 amp 110 circuit?

For example: For a typical installation ...is the wiring run in 1/2 or 3/4 " Schedule 40 or Schedule 80 rigid conduit running along or underneath the edge of the dock with a GFI breaker on shore before power goes to the dock and another GFI breaker at boat lift motor. Does the conduit need to be continous or are PVC weatherproof juction boxes acceptable along the way?