Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Section 4--NSS > Bowditch > Flashcards

Bowditch Flashcards

1
Q

What is Bathymetric Navigation?

A

Uses topography of the sea floor to acquire positioning data.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is Inertial Navigation?

A

Navigation accomplished by integrating the output of a set of sensors to compute position, velocity, and attitude. Includes gyros and accelerometers.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

List 8 types of Navigation.

A 
Bathymetric
Celestial
Dead Reckoning
Inertial
Piloting
Radio
Radar
Satellite
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the exact length of a Nautical Mile?

A

1852 meters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a great circle?

A

The line of intersection of a sphere and a place through the center of the earth. The largest circle that can be drawn on the Earth’s perimeter.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which way do lines of latitude run? What are their units?

A

East West

Degrees north / south

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which way do lines of longitude run? What are their units?

A

North South

Degrees east / west

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Where is 0 degrees of latitude?

A

Equator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where are the 90 degree points of latitude?

A

Poles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Define latitude.

A

Angular difference from the equator.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Define longitude.

A

Angular difference from the prime meridian.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the difference between 2 meridians called?

A

Departure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a Rhumb Line?

A

A line connecting 2 points that crosses all meridians at the same angle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

In a scale of 1:80,000, approximately how much does an inch scale to?

A

1 inch on chart ~= 80,000 inches of Earth ~= 1 NM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the 4 types of charts?

A

Sailing
General
Coastal
Harbor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the smallest scale charts sued for long voyages, and what scale would you normally see on them?

A

Sailing charts

1:600,000 and smaller.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are General charts used for, and what scales do they range?

A

Coastwise navigation outside of outlying reefs and shoals.

1:150,000 to 1:600,000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are Coastal Charts used for, and what scales do they range?

A

Inshore coastwise navigation, entering & leaving bays and harbors.

1:50,000 to 1:150,000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are Harbor Charts used for, and what scales do they range?

A

Navigation and anchorage in harbors and small waterways

1:50,000 or larger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

In what reference would you find chart symbols?

A

US CHART No. 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

On a chart, what is a “No Bottom” Sounding? What does it look like?

A

A number with a line over the top and a dot over the line.

The spot was sounded to the depth indicated without reaching the bottom.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What sounding datum is typically used for NOAA charts in US and PR?

A

Mean Lower Low Water (MLLW)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How do you know if a sunken wreck is dangerous, and what depth must it be at to qualify as dangerous?

A

Dotted curve surrounds the wreck on the chart

Any depth less than 30 m

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Discuss what “6” Fl(2) R 10s 80m 19NM means.

A 
Light #6
Group flashing; 2 flashes
Red
2 flashes in 10 seconds
You can see the light out to 80 meters height, 19 NM away
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

For buoys, what do the letters C, N, or S indicate?

A

Can
Nun
Spar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How do you know if a buoy or NAVAID is privately owned?

A

It is marked with “Priv” on the chart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How accurate is an official chart?

A

1 NM is accurate within 6 feet of the correct length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How many feet is a NM?

A

6080

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What datum do most charts use?

A

WGS 84

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What chart scale would you need to look IOT review a Traffic Separation Scheme?

A

1:600,000 and higher

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Is ECDIS-N and Electronic Chart System the same?

A

Nope. ECS is a chart system that doesn’t meet the level of standard as ECDIS-N.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

ECDIS-N: What is ENC and ECDB?

A

ENC The databse issued for use with ECDIS with all chart information necessary for safe NAV

ECDB The ditial database from which electronic charts are produced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is a RASTER chart? What is a VECTOR chart?

A

Raster A digital image of a chart on one single layer. HUGE file, many pixels.

Vector A digilta chart with a ton of layers that you can hide or alter.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What publication requires us to always carry charts?

A

SOLAS, Chapter V

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is IBS designed to do?

A

Integrate all bridge sensors and controls to mitigate chances of grounding/collision while also providing automated control.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

ECDIS: What is DNC?

A

Digital Navigation Chart. A vector chart produced by NGA.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

How many DNC regions exist in the database?

A

29

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

How many DNC charts exist?

A

5,000+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What is Tactical Ocean Data (TOD)?

A

An overlay to DNC that provides military-centric layers, such as OPAREAs, ranges, bottom contours, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What is Sailing Directions?

A

Consists of 37 Enroutes and 5 Planning Guides to assist with voyage planning

Includes elements like dangers, currents, weather, wind, port facilities, tides, ice, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is US Coast Pilots?

A

A collection of 9 supplemental charts that give US harbor details from surveys. NTM updates this document.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is Light List?

A

Comprehensive list of lights in US waters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What is List of Lights?

A

The international version

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is Luminous Range?

A

MAX range at which an observer can see a light under existing visibility.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What is the term for the distance in which a light can be seen in weather conditions where VIS is 10NM?

A

Nominal Range

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

In what document would you find an explanation of the IALA Buoyage System?

A

Chart No. 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What is the World Port Index?

A

Contains a tabular listing of thousands of ports throughout the world, including the locations, characteristics, facilities, and services available.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What is Distances Between Ports?

A

Lists the distances between major ports, including reciprocal distances on different routes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What is Pub. 151?

A

Distances Between Ports (same publication)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

How are buoys classified?

A

Lighted or unlighted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What are the 3 parts to a lighted buoy?

A

Buoy Hull
Buoy superstructure
Counterweight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What is a Pillar Buoys?

A

A lighted buoy with a circular base

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

How are Unlighted Buoys typically classified?

A

Shape (can, nun, special purpose)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What is an ODAS Buoy? What does it stand for?

A

Ocean Data Acquisition System

A buoy moored or free-floating in offshore waters for science and data collection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Roughly how long is the anchor chain below the buoy?

A

Roughly 3 times the water depth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

What types of sounds are Sound Buoys mounted with?

A

Bell
Gong
Whistle
Electronic Horn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

What does a Wreck Buoy specifically signify? Where is it NOT located?

A

A wreck is nearby, and a hazard. It is NOT located directly above the wreck…

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

What abbreviate does a WRECK buoy show on a chart?

A

WR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Define Beacon.

A

A stationary, short range visual aid to navigation that is fixed to the earth.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

List 5 types of beacons.

A 
Lighthouse
Lights
Ranges
RACONs
Daybeacons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

What is a Major light? What is a Minor light?

A

Major High-intensity light with a nominal range of at least 10 NM

Minor Less intense light with a nominal range < 10 NM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

For buoy lights, what is an Eclipse?

A

The dark period during a light sequence.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Describe what it means for a buoy to be FLASHING.

A

Period of light visible is shorter than the Eclipse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Describe what it means for a buoy to be OCCULTING.

A

Duration of light in a period is longer than the total duration of darkness. Intervals of darkness are equal in duration.

65
Q

Describe GROUP OCCULTING.

A

An occulting light for which a group of eclipses is regulator repeated.

66
Q

Describe COMPOSITIE GROUP OCCULTING.

A

Same, except that successive groups in a period have different numbers of eclipses.

67
Q

Describe ISOPHASE.

A

A light for which all durations of light and darkness are clearly equal.

68
Q

What are the 2 types of buoyage systems? Describe them.

A

Lateral Used in areas with well-defined channels

Cardinal Used in areas with fucked up rocky coasts and lots of dangers

69
Q

What does IALA stand for?

A

International Associated of Lighthouse Authorities

70
Q

What countries use IALA B?

A

N / C / S America, Japan, Korea, Philipplines

71
Q

What are the 5 basic buoy shapes?

A 
Can
Cone
Spar
Pillar
Sphere
72
Q

Which of the 5 shapes has a shape of significant, and what is the significance?

A

Can, Conical, Sphereical. The shape indicates the correct side to pass

73
Q

What are the 4 types of Topmarks?

A

Can
Conical
Spherical
X-shaped

74
Q

Describe a cardinal mark.

A

Used with the compass to indicate where the mariner may find the BEST navigable water. Placed in 1 of 4 quadrants (N, S, E, W) bounded by true bearings. A mariner is safe if the pass NORTH of the NORTH mark, EAST of the EAST mark, etc.

75
Q

Describe the topmark, color, shape, and light for a DANGER Mark.

A

A black double-sphere

Black buoy with one or more red horizontal stripes

Pillar or spar buoy, if it’s a buoy

White flashing light showing a group of 2 flashes (2 flashes to represent the 2 balls!)

76
Q

Describe Safe Water Markers.

A

Indicates that there is navigable water around the mark. Red and white verical stripes with a spherical, RED, topmark.

77
Q

What would you use IALA Special Marks for?

A

ODAS buoys, Traffic separation marks, Recreation Zones, Cable pipelines, etc.

78
Q

What color are special marks? What is their topmark? What color is their light?

A

Yellow mark
Yellow X
Yellow light!

79
Q

How do preferred channel buoys/beaons work?

A

They are banded horizonally with red/green to mark junctions or bifurcations which may be passed on either side.

If topmost band is GREEN:
Preferred channel will be followed by keeping the NAVAID to PORT when entering from sea

If topmost band is RED:
- Preferred channel will be followed by keeping the NAVAID to STBD when entering from sea (red on right returning)

80
Q

What color are nuns and cans?

A

Red nun

Green can

81
Q

What color are special purpose buoys?

A

Yellow

82
Q

What are 3 types of magnetism your ship will have?

A

Permanent
Induced
Subpermanent

83
Q

What direction does a magnetic compass point towards?

A

Magnetic North (not True north)

84
Q

What is the difference between where the compass points and True North?

A

Variation

85
Q

What is another word for variation, but is seldomly used?

A

Declination

86
Q

What is the World Magnetic Model?

A

A magnetic model used by the DoD, NATO, etc. for navigation, attitude, and heading referencing systems using the geomagnetic field.

87
Q

What is Subpermanent Magnetism?

A

The magnetism in the various structures of a ship, which tends to change as as result of cruising, vibration, or aging, but which does not alter immediately to as to be properly termed Induced Magnetism.

88
Q

Why is Subpermanent Magnetism important?

A

It is the principal cause of Deviation changes ona. Magnetic compass.

89
Q

What is the total of all combined errors of the gyrocompass, and what units does it have?

A

Gyro Error

Degrees E/W

90
Q

What are the errors for which a gyrocompass is subject?

A 
Speed
Latitude
Ballistic Deflection
Ballistic Damping
Quadrantal
Gimballing
91
Q

Describe how magnetism affects a gyrocompass.

A

It doesn’t — therefore it is not subject to variation or deviation

92
Q

What’s the NEGATIVE about a gyrocompass?

A

It requires a constant course of stable electrical power. If power is lost, it requires several hours to settle on the meridian again before it can be used.

93
Q

Where is the gyrocompass on a warship, and why?

A

Closest to the center as possible, which minimizes errors caused by the ship’s motion

94
Q

What are some advantages of a DFGMC and a RLGC?

A
  • No moving parts
  • Low power ops
  • Standard digital output
  • Zero friction
  • Rapid startup and self-alignment
  • Self-correction
95
Q

What are 2 types of Optical Gyroscopes?

A

RLG

Fiber Optic Gyroscope

96
Q

How does a RLG work?

A
  • Device sends a beam of light into a beam-splitter, causing 2 beams of light in opposite directions around a ring.
  • Light beams meet, combining into a standing wave which changes in direct relation to the direction and velocity of ship’s movement.
  • If there’s no rotation on the ship, the path lengths will be the same and the beams will recombine in phase.
  • If the device rotated, there will be a difference in the length of paths of the 2 beams, which results in detectable phase differences.
  • This is digitally output into a readout interpretable by a Helm on the SCC
97
Q

Define variation and deviation and compass error.

A

Variation: Diff. between magnetic heading and true heading.

Deviation: Difference between the compass heading and the magnetic heading.

98
Q

What are the 2 TRs for assisting in correcting/uncorrecting the compass?

A

Compass least, error east; compass best, error west.

When correcting, add easeterly errors and subtract westerly errors.

CDMVTAE Compass Deviation Magnetic Variation True, Add East

99
Q

Does set and drift go into DRs?

A

Nope

100
Q

What is the charted symbol for a DR?

A

Semicircle on the course line

101
Q

What is the charted symbol for an Estimated Position?

A

Small square and time

102
Q

What factors affect DR position accuracy?

A

Set
Drift
Leeway

103
Q

What is set and drift?

A

Set Direction of the current

Drift Speed of the current

104
Q

What is the Estimated Track Made Good?

A

The direction of a straight line from the last fix to the Estimated Position (EP)

105
Q

What is estimated speed made good?

A

A time-speed-distance calculation based on the ETMG

106
Q

How do you calculate MIN DEPTH of your vessel for marking shoals on a paper chart?

A

MIN DEPTH = draft – height of tide + safety margin + squat

107
Q

What 3 evolutions should be completed prior to piloting?

A

Testing ASTERN bells
Make anchor ready for letting go
Calculate gyro error

108
Q

What criteria go into choosing an anchorage?

A 
Water depth
Bottom type
Proximities:
-	NAV HAZ
-	Adjacent ships
-	Traffic lanes
Weather
NAVAID availability
109
Q

What types of bottom should you avoid, and what times should you select?

A

Avoid rocky bottoms

Select sandy/muddy bottoms

110
Q

What is your swing and drag circle distances?

A

Drag: Length of the chain plus the distance from hawsepipe to pelorus
Swing: Length of ship + length of chain

111
Q

When is a TSS officially approved for use?

A

When adopted by the IMO (International Maritime Organization)

112
Q

What’s the charted symbol for a TSS boundary?

A

Thick purple dotted line

113
Q

List 5 forms of Vessel Traffic Services (VTSs).

A 
Information Service (INS)
Traffic Organization Service (TOS)
Navigatino Assistance Service (NAS)
AIS
Ports and Waterways Safety System (PAWSS)
114
Q

What are EPIRBs?

A

Emergency Position Indicating Radiobecons

Automatically alert rescue authorities and indicate distress locations.

115
Q

What are the 3 frequencies used in the EPIRB system?

A

121.5 / 243 MHz (aircraft emergency)

406

116
Q

Where are these beacons required?

A

300+ ton cargo and passenger ships

117
Q

What are the 2 categories of 406 MHz EPIRBs?

A

Type 1: Float-free, automatically activated. Detectable by satellite anywhere n the world

Type 2: Same as above but manually activated.

118
Q

Tides: what is stand?

A

The period at high or low water during which there is no apparent change of level

119
Q

What are the 2 sources that cause tide, and which one is the main cause?

A

Moon (Main cause)

Sun (only 46% of the moon’s pull)

120
Q

Where might you find diurnal tides?

A

Gulf of Mexico

Gulf of Tonkin

121
Q

Where might you find semi-diurnal tides?

A

Boston

East coast

122
Q

What are the 3 types of tides? Define them.

A

Semi-diurnal (2 high and 2 low tides each day)
Diurnal (1 high and 1 low tide each day)
Mixed

123
Q

Define Spring and Neap Tides.

A

Spring Sun, moon, and earth are aligned. Greater tide ranges occur.

Neap Sun and moon are acting at right angles to the Earth. Ranges are less than average.

124
Q

What is a Perigean tide?

A

Tides that occur when the moon is at its closest point to the earth

125
Q

What is a Apogean tide?

A

Tides that occur when the moon is at its farthest point from the earth

126
Q

Define: MLW, MLWS, MLLW, TcLLW, ISLW, MLLWS, LNLW, LLW.

A

MLW average height of all low waters for a given place
MLWS Average level of the low waters that occur at times of Spring Tides
MLLW Average height of lower low waters of each tidal day
TcLLW Average height of lower low waters that occur during a tropic tide
ISLOW Indian Spring Low Water. Lwo water datum that includes the spring effect of the tide and the toropic effect caused by the moon’s maximum declination
LNLW (N = normal) Approximates the average height of monthly lowest low waters.
LLW Lowest low water. Absolute lowest tide.

127
Q

What are nontidal currents?

A

Currents not due to tide, such as temporary storm

128
Q

What is slack water?

A

Water with no current

129
Q

What is a hydraulic current?

A

The tide causes by 2 ends of a strait that are not in phase

130
Q

What kind of tide would you normally find offshore? Which direction does it move?

A

Rotary

Clockwise (northern hemisphere), counter clockwise (southern hemisphere)

131
Q

Describe the tropopause and its importance in weather.

A

The area just under the stratosphere. This layer is about 7 miles thick. More than ¾ of air is concentrated within this layer.

Toposphere is about 5 miles to 10 miles high.

132
Q

What is the standard lapse rate of temperature?

A

2 degrees celcius per thousand feet

133
Q

What is a jet stream (air)?

A

A relative strong (> 60 knots) horizontal wind concentrated in a certain area

134
Q

What is a doldrum?

A

A belt of low pressure at the Earth’s surface near the equator, approx.. 30 to 35 degrees on each side (latitude)

135
Q

What is the Meteorological Equator?

A

The equator line that runs through 5 degrees N

136
Q

What are the Trade Winds?

A

A doldrum is located between higher pressure areas. The Trade Winds flow from these higher pressure areas into the doldrums. All about that proximity to the equator.

137
Q

What are the Roaring Forties?

A

Winds in the southern hemisphere in Latitudes 40-50 degrees S that blow between 17-27 knots

138
Q

What are Northeasterlies and Southeaserlies?

A

Polar winds that blow from the poles and outward. N = Artic, S = Antarctica

139
Q

What is a polar front?

A

Where polar esaterlies meet westerlies, near 50 degrees N and 50 degrees S, the temperature and wind suffer a discontinuity

140
Q

Define Frontal Zone.

A

A transition zone between two air masses wher ethe density of the atmosphere changes and isobars form a trough of lower pressure.

141
Q

What happens if a frontal zone exhibits a larger density difference?

A

Larger pressure/temperature change and stronger winds

142
Q

Should you be worried about being in a warm front? Why or why not?

A

Maybe. Although you can experience light rain in the warm front, a cold front is likely following it — and cold fronts cause violent squalls with showers.

143
Q

How far ahead of a cold front might you feel the effects at sea?

A

200 miles

144
Q

Describe the Shapiro Keyser Model and its 4 stages.

A

Models the development of a front cyclone over the ocean

1 Incipient frontal wave
2 Frontal fracture
3 Bent-back front and frontal T-bone
4 Warm core seclusion

145
Q

What are 2 types of wind and their characteristics?

A

Anabolic blows up an incline due to heating
Katabatic Blows down an incline

Characteristics:
Foehn Dry, warm wind that initiates from horizontally moving air encountering a mountain barrier

Fall		Cold wind blowing down an incline
146
Q

What causes a sea breeze?

A

At 0900-1100 each day, the coastal land warms, which causes warm air to rise, which draws in cooler air from the sea

147
Q

What causes a land breeze?

A

After sunset, the land cools below sea temperature, and the air above the land cools. Wind flows from land to the sea

148
Q

What are 2 types of waterspouts?

A
  • A tornado that forms over land and then heads over the sea

- A tornado that forms over the sea, lasts an hour max, and has variable strength

149
Q

What are 2 types of fog, and where are they predominantly (generally) seen?

A

Radiation fog (land)

Advection fog (sea)

150
Q

How are Tropical Cyclones classified?

A

Wind speed

151
Q

What are the 4 terms we apply to varying strengths of tropical cyclones, and what wind speed are they?

A

Tropical Depression <= 33 kts
Tropical Storm 34-63 kts
Hurricane 64-96 kts
Major Hurricane 96+ kts

152
Q

What is a typhoon? What is a super typhoon? What is a Bagyo?

A

A hurricane, except in the Pacific

Tropical cyclone with 130kts of wind sustained

It’s what the Philippines calls a typhoon

153
Q

What is a Willy-Willy?

A

A severe tropical cyclone that moves through Australia

154
Q

How can you read the weather to identify and maneuver around a tropical cyclone?

A
  • Presence of an exceptionally long swell
    o In deep water, it approaches from the direction of origin
    o In shoal water, this may not be true
  • Cirrus clouds appear
    o Point of convergence provides an indication of the storm center
    o From your POV, if the point slows shifts in a direction of storm movement, then it will pass well to one side of your
    o From your POV, if the convergence point remains steady, the storm is going to pass very close to you
  • Storm bar appears
    o Darkest part of the cloud is in the direction of the storm
    o Bar appears to drift slowly along the horizon? Storm will pass to one side.
    o Bar remains fixed? Storm is headed straight for you!
155
Q

In the northern hemisphere, which half is the dangerous semicircle of a tropical cyclone?

A

The half to the right of the direction in which the cyclone is heading

156
Q

In the northern hemisphere, you’re in the dangerous semicircle. How do you steer?

A

Place the wind on the STBD bow (045 R). Hold course and make as much way as possible. If necessary, heave to with head to the sea.

157
Q

What about less-dangerous semicircle?

A

Place the wind on the STBD quarter

158
Q

What should you do if you are on the storm track and ahead of the storm?

A

Bring the wind 2 points on the STBD quarter

159
Q

What should you do if you are on the storm track but behind the center?

A

Steer the best practicable course, keeping in mind that tropical cyclones in the NH tend to curve northward and eastward

Section 4--NSS (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions