San Francisco Tides

Time Event Value Units
01:36 am Max Flood 2 kt
03:47 am High Tide 4.32 ft
05:00 am Slack
07:24 am Low Tide 3.7 ft
07:24 am Max Ebb -1.4 kt
10:06 am Slack
12:36 pm Max Flood 1.2 kt
01:27 pm High Tide 5.53 ft
02:24 pm Slack
06:18 pm Max Ebb -3.4 kt
08:44 pm Low Tide -0.21 ft
11:24 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?