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Tidal Diamonds

1) Find a tidal diamond close to the area where you will be boating

2) Locate the tidal diamond data on the chart

3) Here you will also find the directions on what each column means, the information at the top of the column gives you the geographical location in Lat & Long

  • 1st column = Direction of the stream in degrees (True bearing)
  • 2nd Column = Rate (speed) in Knots during a Spring Tide
  • 3rd Column = Rate (speed) in Knots during a Neap Tide
  • 4th Column = Hours of the Tide, 0 = HW time (found in a tide table)

Calculating your speed / how long it will take you: 

Distance ÷ Speed × 60 = Time

 

Example: 

Distance to Travel = 5 nautical miles

Boat Speed = 10 knots

Tidal Stream (flowing with you) = 3.7 knots

Time = 21min 53s

 

Distance to Travel = 5 nautical miles

Boat Speed = 10 knots

Tidal Stream (flowing against you) = 3.7 knots

Time = 47min 37s


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