Dock Hinge System

I used the dock hinge system to attach a 12 ft gangway ramp from a seawall to a floating dock. It made the whole process very easy. Please excuse my joist tape in the pictures, it got a little torn during installation and decking is incomplete.

It looks to me like it is upside down. The top hinge solid piece should be on the bottom so in my case, the ramp, will rest on the solid piece and the bottomhinge (2 piece hingle with the bolt) should close down to secure the hinge system. Then tighten the hinge from under neither. I know that does work well in water but it appears to me it would be strong and hold more.

Great quality, but they only rotate about 80 degrees to each side. One of the videos makes it look like they can rotate at least 90 degrees. I was hoping to use one of mine with 90 degrees as the neutral position, but that did not work.