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Tides for Sea Kayakers

Tides for Sea Kayakers. Overview. What is a Tide? Types of Tides – Spring and Neap High and Low Tides Rule of Twelfths Calculation of Tides at Secondary Ports Calculation of Currents at Secondary Stations Tide Races and Over falls Tidal flow direction. What is a Tide?.

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Tides for Sea Kayakers

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  1. Tides for Sea Kayakers

  2. Overview What is a Tide? Types of Tides – Spring and Neap High and Low Tides Rule of Twelfths Calculation of Tides at Secondary Ports Calculation of Currents at Secondary Stations Tide Races and Over falls Tidal flow direction

  3. What is a Tide? Tides are the vertical rise and fall of the ocean level due to the gravitational and centrifugal forces between the earth and the moon and to a lesser extent the sun.

  4. High and Low Tide High tide is when the water stops rising (Also known as HighWater). Low tide iswhen the tide stops dropping is Low Water or low tide Slack Water is when there is NO movement of water in either direction.

  5. Different Tidal Patterns Diurnal Tide Semi Diurnal Tide Mixed Tide

  6. Semi-diurnal Tidal Pattern In general in most of the world, the tides go up and down on a semi diurnal curve. A Semi-diurnal tide has two high tides and two low tides in a lunar day (24.8 hours).

  7. Diurnal Tidal Pattern A Diurnal tide is a tide with one low and one high tide in a lunar day (24.8 hours).

  8. Mixed Tidal Pattern Mixed tides are a diurnal and a semi-diurnal tide within the same geographic area. Mixed Semi-Diurnal Tides have two different ranges in tide levels

  9. For kayakers to remember: A Diurnal Tide has a 24 hour 50 min cycle. A Semi Diurnal Tide has a 12 hour 25 min cycle. Tidal Patterns

  10. Tidal Patterns Around the Earth

  11. Cause of different Tidal Patterns

  12. The Four Phases of the Moon

  13. Consider the general rule of twelfths: The flow of water between low and high tide is divided into a 6 hour period. The first hour will move 1/12 of the total volume of the tide. The second hour will move 2/12. The third hour will move 3/12. The fourth will move 3/12. The fifth hour will move 2/12. And The sixth hour will move 1/12. As a result the middle two hours move roughly half of the tidal volume. Rule of Twelfths

  14. TIDAL FLOW Tidal flow can be augmented by a number of factors: • Shallow water • Headlands • Constrictions • Wind direction

  15. Tidal Races and Overfalls

  16. Reading Tide Tables If we were to plan a paddle up Indian Arm launching at Deep Cove on Saturday October 5 when would it be a good time to launch?

  17. Reading Current Tables . You have to catch a Ferry back to the mainland at Departure Bay on October 19th and have to travel North though False Narrows, when would you attempt this in a kayak? Hint: A Flood tide travels north through False Narrows – from marine chart.

  18. Tide Take-aways Know your tidal type (mixed, diurnal semi-diurnal) Know when high and low tide occur Know when neap and spring tides occur Know the rule of twelfths for peak flow Check the tidal tables before getting on the water Be aware of tidal races and where they occur Be aware of tidal directional flow and it’s variance around land masses

  19. THE END

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