Waves & Wind

Question 1

What is wavelength?

Answer 1

Horizontal distance from crest of one wave to crest of another wave.

Question 2

What is height in terms of waves?

Answer 2

Vertical distance from crest to trough.

Question 3

What is the period of a wave?

Answer 3

Time it takes for successive crests to pass a given point.

Question 4

When do waves break?

Answer 4

Waves break when the water depth is 1.5 times the wave’s height.

Question 5

What causes alternating tides?

Answer 5

The attraction of the sun and moon causes alternating tides.

Question 6

Which celestial body has a stronger effect on tides?

Answer 6

The moon has a stronger effect on tides due to its closer proximity.

Question 7

What is a semi-diurnal tide?

Answer 7

A semi-diurnal tide consists of 2 high tides and 2 low tides occurring approximately every 24.5 hours.

Question 8

What is the tidal range in Southern Maine?

Answer 8

Tidal ranges in Southern Maine vary from high tide to low tide, reaching up to 11ft to -18in

Question 9

What is a diurnal tide?

Answer 9

A diurnal tide consists of 1 high tide and 1 low tide occurring every 24 hours.

Question 10

What are spring tides?

Answer 10

Spring tides occur twice a month when the moon has the greatest influence on tides.

Question 11

When do tides rise highest?

Answer 11

Spring tides

Question 12

What is the best time for tide planning?

Answer 12

neap tides

Question 13

Slack tide

Answer 13

Still tide between high and low

Question 14

What causes onshore winds?

Answer 14

Onshore winds are caused by the difference in temperature and pressure between land and water.

Question 15

What causes offshore winds?

Answer 15

Offshore winds occur when the land cools more rapidly than the water, creating a pressure difference.

Question 16

Working with Currents

Answer 16

• largest effect ferry angle = 60° off course
• bow and quarter currents take less correction than full and beam
  -bow currents slow you down
• Quarter currents speed you up
• Use eddies to work us shoreline

Question 17

Prevailing winds in Maine

Answer 17

Summer - Southwest
Winter- Northwest
Coming from the direction

Question 18

Fetch

Answer 18

Unobstructed distance over which wind travels creating waves

Greater the fetch distance the greater the wind can create larger and more powerful waves 

Question 19

What are beam winds?

Answer 19

Wind from side

Question 20

What are head winds?

Answer 20

Wind from front

Question 21

What are tail winds?

Answer 21

Wind from behind

Question 22

What are quartering winds?

Answer 22

Wind from angle

Question 23

What is a dumping wave?

Answer 23

Caused by steep drop in sea floor, bottom wave, reaching critical that shallow depth quickly and breaks suddenly 

Question 24

Ripples

Answer 24

Smallest waves

Produced by wind moving across still water

Question 25

What is the importance of Wave timing?

Answer 25

Wave period affects the process of launching and landing on the beach.

Question 26

What is the effect of a longer wave period?

Answer 26

A longer wave period results in a slower process and more time to get clients through.

Question 27

What is the effect of a shorter wave period?

Answer 27

A shorter wave period results in a faster process.

Question 28

When is tidal flow the strongest

Answer 28

Middle 2 hours

Question 29

Rule of 12ths

Answer 29

A way of tracking water movement over the change of high to low tides. 6 hours 1/12 goes in the 1st hour, 2/12 in the 2nd hour, 3/12 in the 3rd hour, 3/12 in the 4th hour, 2/12 in the 5th hour, and 1/12 in the 6th hour. So 1/2 of the water movement is in the middle 2 hours

Question 30

Reflection

Answer 30

Waves hitting a barrier causing choppy seas

Question 31

Wave height

Answer 31

Concerns:  are clients visible, can clients remain upright  Vertical distance separating the crest from the trough 

Question 32

Steep standing waves

Answer 32

Caused by wind blowing against tidal stretch

Question 33

What determines wave size?

Answer 33

Determined by wind, speed, duration, and fetch 

Question 34

What is the impact of tides on kayaking?

Answer 34

Avoid mud flats, avoid hazardous areas when current is strong get free ride and wrong direction. Know where to pull boats on beach know where to explore/avoid river channels.

Question 35

Current strength

Answer 35

Strong = 1.5 knots or greater Modest = .5 - 1.5 knots Weak = less than .5 knots

Question 36

Clapotis

Answer 36

 explosive water  waves hit a surface for example a harbor wall or another wave. This makes the wave double in size.

Question 37

Determining direction and speed of current

Answer 37

Determining current direction: - field observation, NOAA reports books DETERMINE CURRENT SPEEDS : -NOAA reports, boat drift, current (knots) equal 60 x drift

Question 38

Rip

Answer 38

Water moving at a different speed from that of the water adjacent to it

Question 39

Types of breaking waves

Answer 39

Spilling breaks, plunging breaks, surging brakes

Question 40

Spilling breaks

Answer 40

Gently sloping waves break slowly over a long distance

Question 41

Plunging brakes

Answer 41

Moderate slope wave slow down crest curls front of wave

Question 42

Surging brakes

Answer 42

Steep slope wave builds suddenly breaks right on beach

Question 43

Ideal landing surf

Answer 43

Flat beach and spilling waves

Question 44

Refraction

Answer 44

When waves bend inward and pile up near land creates rough seas

Question 45

Waves

Answer 45

Caused by wind Crest equals highest part  Trough equals lowest part  soup name given to wave after it breaks