San Francisco Tides

Time Event Value Units
12:38 am Slack
03:29 am Max Flood 1.4 kt
05:10 am High Tide 5.42 ft
05:41 am Slack
09:59 am Max Ebb -2.4 kt
12:35 pm Low Tide 1.16 ft
03:34 pm Slack
06:00 pm Max Flood 1 kt
07:45 pm High Tide 3.46 ft
08:38 pm Slack
11:02 pm Max Ebb -1.1 kt
11:16 pm Low Tide 3.08 ft
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?