hi all
Referring to what Dicky has drawn - its quite feesible. However, what we must remember is that the position of a boarding plank isnt always from deck down to quayside or from deck up to quayside. Sometimes a boarding plank has to move through a variety of angles as the ship moves up/down with the tide.
If the formation of the steps is at a triangle shape, when the ship is level with the quayside these points would then be very difficult to walk on.
I think the triangle has a broad flat top on it and also if you have a close look, you will see where the checkered aluminium plate has been bent to form the shape and then riveted to the next piece. The best people would be either Shipmates60 or PShips to give a better answer/description.
Here's my interpretation
aye
john
bluebird