San Francisco Tides

Time Event Value Units
01:00 am Slack
04:00 am Max Ebb -3.3 kt
05:15 am Low Tide 1.05 ft
07:24 am Slack
10:12 am Max Flood 3.2 kt
11:43 am High Tide 6.53 ft
12:42 pm Slack
04:06 pm Max Ebb -4.5 kt
06:02 pm Low Tide -0.61 ft
08:18 pm Slack
11:06 pm Max Flood 3.2 kt
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?