San Francisco Tides

Time Event Value Units
12:40 am Max Ebb -1.4 kt
01:17 am Low Tide 3.49 ft
03:32 am Slack
05:46 am Max Flood 0.9 kt
07:05 am High Tide 5.58 ft
07:30 am Slack
12:14 pm Max Ebb -2.9 kt
02:28 pm Low Tide -0.14 ft
05:11 pm Slack
07:54 pm Max Flood 2.2 kt
10:00 pm High Tide 4.37 ft
10:58 pm Slack
What day is the longest?
Why are there 2 tides per day?
Why doesn't Slack = High/Low Tide?
Why can you ride a flood but not an ebb?