The crossing bell

At low tide the ferry ramp was exposed, and its lower section was slippery with wet weed. A crew member directed passengers towards the handrail while another checked tickets at the top. I had crossed this water many times without looking at the ramp closely. Waiting for my turn gave me time to notice its patches, bolts and worn painted line. The boat was familiar; the narrow connection between it and the shore suddenly seemed worth more attention.

From the passage, select two words or phrases that describe the condition of the ramp's lower area at low tide.