San Francisco Tides

Time Event Value Units
01:06 am Slack
03:48 am Max Flood 1.9 kt
05:57 am High Tide 5.23 ft
07:00 am Slack
10:42 am Max Ebb -2.4 kt
12:30 pm Low Tide 1.87 ft
03:06 pm Slack
04:48 pm Max Flood 0.8 kt
06:05 pm High Tide 3.55 ft
07:18 pm Slack
10:30 pm Max Ebb -1.9 kt
11:33 pm Low Tide 1.85 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?