I will bring 100+ feet of poly rope with marks, a kayak and gear, a pole that doesn't float with a tether and markings of depth in feet and tenths.

John, I assume you can get inside the gates (I can come by kayak!).

If we use lines drawn to the center of slips as references, we will be able to get the kayak inside the slips and measure there, to correlate with the existing data.  The docks differ in length, so we will need to improvise at the NE ends, as well as outside of the A-dock and E-docks.  The alignment of the finger docks are pretty good, so sighting along the edge of those might be all that is needed.  We will learn as we go!!