An issue with this example?

Hi Grant Regarding the example below, to clarify my understanding, won't more of the rock will be visible at 1030 at low tide, not below the surface? " This above means that in Eastport on the 31th August at 1030 am, the depth of the water will be 2.6 feet below the chart datum depth at any point. e.g. if the harbor reads 7.0 feet deep at a certain point, then the real depth at 1030 will be 7.0 - 2.6 = 4.4m. Or if the chart shows a rock at 2 ft above the datum, at 1030 it will be below the surface. For a 5 ft draft and at 4.4 ft real depth, this could be a grounding situation, even though the chart says 7 ft.