San Francisco Tides

Time Event Value Units
12:01 am Low Tide 3.59 ft
02:23 am Slack
04:39 am Max Flood 0.8 kt
06:01 am High Tide 5.38 ft
06:16 am Slack
11:04 am Max Ebb -2.5 kt
01:39 pm Low Tide 0.28 ft
04:34 pm Slack
07:23 pm Max Flood 1.8 kt
09:30 pm High Tide 4.15 ft
10:18 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?