chapter 8: tides and tidal currents

Navigation Study GuideF

loti

lla 1

2-10

Chapter 8: Tides and Tidal CurrentsInstructor: Forrest Meiere

All Questions are important for exam

PowerPoint Presentation

by Forrest Meiere


loti

lla 1

2-10

the maximum height reached by each rising tide; and low water denotes the minimum height reached by each falling tide

S8-2. The term high water denotes ______________

S8-1. Tides and currents arise from the same forces and, although related, are distinct terms. Tide refers to the . motion of the water, tidal current to the ._________ flow of the water.verticalhorizontal


loti

lla 1

2-10

difference between consecutive high and low waters .

S8-4. There are three principal daily patterns observed for tides: _______,____________ and ______.

S8-3. Tidal range is defined as the _________________

Diurnal Semidiurnal mixed


loti

lla 1

2-10

S8-6. When the moon and the sun are "pulling together," larger tidal ranges, termed ____________, occur.

S8-5. In addition to the daily tide patterns, there are more subtle patterns with a longer period. Tides have decreased range when the moon is in ________ and increased range when the moon is in ________.

ApogeePerigee

Spring Tides


loti

lla 1

2-10

S8- 7. Alternatively, when the gravitational force of the sun and the moon are at right angles, tides with smaller range, termed __________, occur.Neap tides

S8-8. In the United States and certain other parts of the world, the vertical reference plane or datum is what is termed _____________________________.mean lower low water (MLLW)


loti

lla 1

2-10

difference in height between mean high water and mean low water.

S8-9. Locations for which tidal predictions can be made with the aid of the Tide Tables are subdivided into two classes: _______________ and ___________________.

S8-10. The mean range is defined as the _____________

reference stations subordinate stations


loti

lla 1

2-10

S8-11. The spring range is defined as _______________

S8-12. The mean tide level (also termed half-tide level) is defined as __________________________________ a plane midway between mean low water

and mean high water, measured from chart datum.

average semidiurnal range occurring semi-monthly as a result of the moon’s being new or full.


loti

lla 1

2-10

S8-13. Three common errors made by students in tide height calculations are: _________________________

S8-14. Three methods for estimating tidal currents include: _____________________________________

a. neglecting to convert from daylight to standard time, b. not being alert to date changes when calculating tides for subordinate stations, and c. applying high water time differences to low water or converse.

a. observed directly from the movement of the water around stationary objects, b. calculated as you go using the methods of current sailing, and c. estimated or calculated from various published aids.


loti

lla 1

2-10

a tidal current which flows alternately in approximately opposite directions with a slack water at each reversal of direction.

S8-15. Data given in the Tidal Current Tables for reference stations include ______________________

S8-16. A reversing current is defined as _____________

the time of all slacks, the time and strength of ebbs and floods and the direction of the ebb and flood.


loti

lla 1

2-10

the most advantageous time of departure to maximize fair currents over the intended voyage route.

S8-17. A rotary current is defined as ________________

S8-18. The most important use of the Tidal Current Diagrams is to determine ______________________

a tidal current that flows continually with the direction of flow changing through all points of the compass during the tidal period.

chapter 8: tides and tidal currents

Documents