I decided to build my 16'x4' dock from a combination of steel, wood, and composite. The posts were built from 3"x1"wall steel pipe with a 1'x1'x 3/4" steel plate welded to the bottom at a slight angle to match the slope. I then welded a 30"x 1" Pin (salvaged anchor bolts for concrete barrier) to the bottom. The main frame was constructed of 4x4x1/4" angle iron welded. I drilled two holes approx. 12' out 3" and welded 3"id x 3 1/2" pipes over the holes. The 3"x3 1/2" short pipes had 2 1" holes in each which I welded 7/8" nuts to. The posts slipped through the frame and short pipes and bolts could be tightened to clamp the post. This design allows the dock to be adjusted if needed. The bank side had concrete piers dug 30" deep. I used concrete tubes for this. The entire frame was coated with organic zinc, epoxy, followed by a coat of urethane. Joists were laid across the angles, I used 4x4s left over from a fence I had to redo because the wife wanted vinyl (that's another story). Over the 4x4's I laid the composite decking. It stays cool, has good traction when wet, doesn't rot and requires no sealer. I do bridge construction so all the steel and paint was free but I still would have not done it any other way. Check out the picture
Dock photo
