ATSC 113 Sailing Modules Exam
Questions with Correct Answers
rogue waves - Answer-these freak waves occur due to interference and result in a wave
crest higher than the theoretical maximum
interference - Answer-when two waves intersect they either cancel each other out or
add each other up
destructive interference - Answer-waves that cancel each other out and calm down
constructive interference - Answer-waves that add each other up and create a bigger
wave
rogue waves - Answer-constructive interference of waves
tsunami - Answer-caused by seismic events
when the bottom of a wave meets the ocean floor - Answer-the wavelength is reduced
wave height increases due to lagging waves building up behind the waves in front
if the ratio of height:length exceeds 1:7, the wave breaks due to instability
slope of the sea floor, tide and direction - Answer-influences the speed and type of
wave break
spilling breakers - Answer-occur across gently sloping sea floors, white water spills from
the crest down the front
plunging breakers - Answer-occur over a moderately steep sea floor, the crest falls in a
curl forward with considerable energy
surging breakers - Answer-Steepest sea floor
Energy spread over shortest distance
Best for body surfing
Waves rapidly slide up the beach
swell direction - Answer-forecast in degrees where 0=north and 180=South from where
the swell is coming FROM
wave height - Answer-measured by a buoy in feet/meters
onshore winds - Answer-blow from the ocean onto the shore, creates chop, reduces
wave steepness
, offshore winds - Answer-blow from land to water, slow down the incoming waves,
smooths the face of breaking waves
tide - Answer-affects how the waves break because it changes where the break occurs,
is the movement of the ocean's surface up and down due to the gravitational pull of the
moon and sun
confused sea - Answer-mixed interference of several wave trains coming in different
directions and/or with different wave lengths and heights
swell refraction - Answer-As the swell hits the shallower part the rest of the wave starts
to curve such that wave becomes more parallel to the shoreline.
Swells w/ longer wave periods refract more.
swell decay - Answer-how quickly waves lose energy as they travel away from their
initial source
New Moon - Answer-A moon that is completely dark because it's unlit side is facing
Earth
full moon - Answer-moon phase when the entire side facing Earth is illuminated.
quarter moon - Answer-when the sun an moon are at right angles to each other, half of
the moon is illuminated
spring tide - Answer-when the sun and moon line up (during new and full moons) their
forces add to each other, creating higher and lower tides than usual
neap tide - Answer-during quarter moon phase, weaker tides because the sun and
moon exert opposing forces on each other
tidal range - Answer-shown on a graph plotting day and height of highest and lowest
tides
tide tables - Answer-predict the time and height of high and low tides
tidal currents - Answer-horizontal flow of water accompanying the rise and fall of the tide
flood current - Answer-incoming tide
ebb tides - Answer-outgoing tide
slack tide/current - Answer-the moment when the tide turns and the current ceases and
reverses direction
Questions with Correct Answers
rogue waves - Answer-these freak waves occur due to interference and result in a wave
crest higher than the theoretical maximum
interference - Answer-when two waves intersect they either cancel each other out or
add each other up
destructive interference - Answer-waves that cancel each other out and calm down
constructive interference - Answer-waves that add each other up and create a bigger
wave
rogue waves - Answer-constructive interference of waves
tsunami - Answer-caused by seismic events
when the bottom of a wave meets the ocean floor - Answer-the wavelength is reduced
wave height increases due to lagging waves building up behind the waves in front
if the ratio of height:length exceeds 1:7, the wave breaks due to instability
slope of the sea floor, tide and direction - Answer-influences the speed and type of
wave break
spilling breakers - Answer-occur across gently sloping sea floors, white water spills from
the crest down the front
plunging breakers - Answer-occur over a moderately steep sea floor, the crest falls in a
curl forward with considerable energy
surging breakers - Answer-Steepest sea floor
Energy spread over shortest distance
Best for body surfing
Waves rapidly slide up the beach
swell direction - Answer-forecast in degrees where 0=north and 180=South from where
the swell is coming FROM
wave height - Answer-measured by a buoy in feet/meters
onshore winds - Answer-blow from the ocean onto the shore, creates chop, reduces
wave steepness
, offshore winds - Answer-blow from land to water, slow down the incoming waves,
smooths the face of breaking waves
tide - Answer-affects how the waves break because it changes where the break occurs,
is the movement of the ocean's surface up and down due to the gravitational pull of the
moon and sun
confused sea - Answer-mixed interference of several wave trains coming in different
directions and/or with different wave lengths and heights
swell refraction - Answer-As the swell hits the shallower part the rest of the wave starts
to curve such that wave becomes more parallel to the shoreline.
Swells w/ longer wave periods refract more.
swell decay - Answer-how quickly waves lose energy as they travel away from their
initial source
New Moon - Answer-A moon that is completely dark because it's unlit side is facing
Earth
full moon - Answer-moon phase when the entire side facing Earth is illuminated.
quarter moon - Answer-when the sun an moon are at right angles to each other, half of
the moon is illuminated
spring tide - Answer-when the sun and moon line up (during new and full moons) their
forces add to each other, creating higher and lower tides than usual
neap tide - Answer-during quarter moon phase, weaker tides because the sun and
moon exert opposing forces on each other
tidal range - Answer-shown on a graph plotting day and height of highest and lowest
tides
tide tables - Answer-predict the time and height of high and low tides
tidal currents - Answer-horizontal flow of water accompanying the rise and fall of the tide
flood current - Answer-incoming tide
ebb tides - Answer-outgoing tide
slack tide/current - Answer-the moment when the tide turns and the current ceases and
reverses direction
