-Stretches very little and can't absorb shock loads
-Resistant to environment
most popular general rope in marine industry
-Breaking strength 1/4" line = 1200 lbs.
What are the characteristics of Kevlar line?
-Safer than Nylon, no snap
-Does not float
-Expensive
-Does not bend repeatedly
-Does not tolerate chafe well
-Degrades in sunlight, requires jacket or sleeve
-Breaking strength 1/4" line = 6600 lbs
What are the characteristics of Spectra/Dyneema (High Modulus Polyethylene HMPE) line?
-What the Navy uses
-40% stronger than Kevlar line
-Almost no stretch
-Resistant to corrosive chemicals
-Self lubricating
-It floats
-Slippery and resistant to abrasion
-Breaking strength 1/4" line = 8000 lbs
What are the characteristics of Polypropylene line?
-Used for applications that require low stretch
-It floats
-Jet ski tow rope
-Susceptible to UV radiation
-Breaking strength 1/4" = 1250 lbs
What is the function Head/Stern lines?
Stop drift away from the pier
What is the function of Spring Line?
Stop FWD/AFT movement
In terms of line: what is a lead?
-the length of line relative to other lines
*On LCS2 line #6 is susceptible to surge loads due to its small length
Define the following
Bitts
Bollards
-Cleats
-Bitts- onship, pair of short steel post or horns on board ship, used to secure lines
-Bollards- steel or iron post on a dock/pier/wharf used in securing a ship's lines
-Cleats- an anvil shaped fitting for securing or belaying lines. Use a locking hitch
What are the characteristics of a Windlass?
-Horizontal shaft
-force/axis is parallel to deck
-riding pawl used as locking mechanism
-warping head used with turning block
What are the characteristics of an anchor Winch?
Horizontal axis of rotation
-Used for anchor equipment, towling lines or mooring lines
-MAy be self-tensioning
-Line is generally stowed on the drum of the wench
What is the purpose:
Fenders
Camels
Yokohamas
Fenders- used to absorb shock
Camels- used to hold things apart, provide separation
Yokohamas- can do both absorb shock and provide separation
Define the following commands:
Put Over
Take In
Hold
Check
Surge
Double Up lines
What are the characteristics of a Capstans?
-Vertical axis of rotation- does not need a turning block
-Less likely to have a wildcat, but more common smaller vessels
1 knot of current will have approximately the same effect as about how much wind?
30 kts
What considerations should you take into account when anchoring?
-water depth
-traffic
-bottom type
-weather
-availability of nav aids
-Drag circle(from anchor to sensor used to determine dragging
-Swing circle (from anchor to Stern of ship)
What is a lee shore?
The direction/area the ship will show, sure to wind. If something goes wrong which way would you drift
What assumption is made on an anchoring nomograph
Assumes current/wind are in same direction
What is the Navy regulation for anchor fastness?
Regulations state that "the ship must be able to lie to a single anchor in a steady 70kt wind and a 4knot current in 40 farting with a firm same bottom
What are the main parts of an anchor (LWT)?
-flukes
-stock(turns anchor over to dig flukes in)
-shank
List different types of anchors?
-Danforth
-Plow
-Bruce
-Rocna
-Mushroom
1 shot equals how many fathoms and feet?
1 shot = 15 fathoms = 90 feet
What is the flag to signal dragging anchor?
International code Y
How much chain and wire does LCS 2 class have?
½ shot of chain and 12 shots of wire
Recommended times the water depth for best holding power?
5-7 times
What is the fix Accuracy and Fix Interval Guidelines for Restricted Waters?
≤2 nm from land
GPS FOM≤2
Fix 3 mins
What is the definition of deviation?
The deflection right or left of the magnetic
meridian caused by magnetic properties of the vessel.
What are the pros/cons of magnetic compass?
-simple and cheap
-Unable to talk to other systems
-Susceptible to variation and deviation
What are the pros/cons of gyro compass?
-True North referenced, not affected by variation
-Requires consistent and steady electrical; power loss can cause gyro tumbling
-Inaccurate above 70° latitude; requires corrections/most accurate at the Equator
-Add easterly erro to compass heading to get true heading
What are the pros/cons of a fluxgate compass?
-Susceptible to to variation and deviation
-Heading will wonder, so dont expect a steady course
-Instant power-on, no need to spin up
-Talks to other systems
What are the pros/cons of Digital gyro/laser ring gyro compass?
-Talks to other systems
-Expensive
-Takes time to spin up to be accurate
What are the pros/cons of Satellite compass?
-Not expensive
-Integrates with other systems
-Fast turn-on
-Robust
-Subject to jamming
-Subject signal refraction
What is the definition of variation?
The angular difference between the true meridian (great circle
connecting the geographic poles) and the magnetic meridian
(direction of the lines of magnetic flux)
1 kt is equal to 1 1/8 mph, so 8kts = ___mph?
8kts = 9mph
How does flux compass work?
Measures horizontal angle of Earth's magnetic flux
What is the fix Accuracy and Fix Interval Guidelines for Open Ocean?
30 nm+ from land
GPS FOM≤7
Fix 30 mins
What is the fix Accuracy and Fix Interval Guidelines for Piloting Waters?
10-20nm from land
GPS FOM≤6
Fix 15-30 mins
What does the List of Lights provide/cover?
-NGA produced
What does the Light List provide/cover?
-USCG produced
-covers US waters and possessions
What are Pilot Charts and what information is contained within?
-Put into its current format by Matthew Maury (Navy)
-Information was gathered from notes and logbooks from multiple nations
-Charts contain
-Wind Rose
-Tropical Cycle
-Mean Sea Surface Temp
-Air temp
-Currents
-Exceptional Sightings
-Visibility,
-Ice
-Wave Height/ percentage of waves over 12 ft
What are the characteristics of the After Action Reports?
-Created by previous USN vessels and contains various observations on approaches, piers, and services
What are the characteristics of the Port Guides or Fleet Guides?
-Navy only ports and separated by Atlantic/Pacific
-Published by NGA
What are the characteristics of the World Port Index?
-Hydrographic Office Pub #150, Lists location, characteristics, facilities, and services available at ports, shipping facilities, and oil terminals throughout the world
What are the characteristics of the Sailing Directions?
-International Waters
-Published by NGA
-Planning guide has local pps information )unit of money, holidays, flags)
What are the characteristics of the Coast PIlots?
-US Waters
-Published by NOAA in 10 volumes
-Chap 1- General Info
-Chap 2- NAvigation
-Chap 3- Narrative description of coast pier services
How is SOG (Speed Over Ground) measured?
-GPS is the most common and usually reliable. Limitations: atmospheric effects, DIW
-Doppler speed indicator
-INS
*LCS-2 has doppler
How is STW (Speed Through Water) measured?
-Pit Sword
-Small boat spinner wheels
-Pressure Stick
-SOLAS (Safety of Life at Sea) requires that all vessels greater than 300GT be fitted with single axis STW SDME(Speed Distance Measuring Equipment). All vessels greater than 50,000GT be fitted with Dual-Axis STW SDME
What are the characteristics of the US Notice to Mariners (NTM)?
-Published by NGA weekly
-Online or email subscription
-Provides corrections for unclassified nautical charts
What are the characteristics of the US Local Notice to Mariners (LNM)?
-Published by USCG Districts (9 total Districts) weekly
-Online or email subscription
-Similar to NTM, but more costal nature
-Information concerning aids to navigation, hazards to navigation, and other items of marine information of interest to mariners on the waters of the of the US, its territories, and possessions
What are the characteristics of a Broadcast NTM?
-Broadcast by USCG
-In US waters broadcast made on VHF 22A. Initial alert will be made on VHF 16
-Generally restricted to ports, harbors and coastal waters
What are the four types of Navigational Warning handled by NGA?
-NAVAREA IV
-HYDROLANT
-NAVAREA XII
-HYDROPAC
What are the characteristics of NAVAREA broadcasts?
-Broadcast 1 time per week by NGA
-NAVAREA IV and XII DO NOT broadcast distress, man overboard or EPIRB messages
Do HYDROLANT and HYDROPAC messages show distress, man overboards and EPIRB messages?
Yes
What messages are released infrequently and contain information about hazards caused by the political climate?
-Special Warnings and Maritime Administration (MARAD) Advisories
What are the characteristics of Daily Memorandum broadcasts?
- Issued daily M-F, excluding holidays
-Contains a summary of Broadcast warning and Special Warnings promulgated during the past 24-72hours
What are the three main classes of Chart Projection?
-Cylindrical: Tangent along great circle, large size rectangular aea
-Conic: Medium size triangular shape
-Planar or Azimuthal: small area
What causes map distortion?
-Distortion is caused by the Earth’s spherical shape. Its impossible to represent the Earth’s shape on a flat paper without distortion
What are some desirable properties in chart projections?
-True shape of physical features
– Correct angular relationships
– Representation of areas in correct proportions relative to one another
– True scale (accurate distances)
– Rhumb lines or Great Circles represented as straight lines
What are the types of Cylindrical Projections?
-Mercator
-Transverse Mercator (tangent circle is on a meridian of longitude)
-Universal Transverse Mercator
-Easy to use, accurate over large area
-Military projection seen superimposed on regular Mercator charts
What are the types of Conic Projections?
Simple or secant (Parallel on 2 straight lines) conic projections
-Lambert Conformal-used for radio beacon signals and aeronautical navigation charts
What are the characteristics of Cylindrical Projections?
-Points are transferred to the inside of a cylinder
-Mercator is the most common, and is the most commonly used for marine navigation
-used because a rhumb line on a Mercator projection is a straight line
What are advantages and disadvantages of Gnomonic Projections?
– Advantages:
• Great Circles plot as straight lines, which are ideal for
long voyages.
• The Distortion is tolerable within about 1,000 miles of
the point of tangency.
– Disadvantages:
• Rhumb Lines plot as curves and do not plot easily on this
type of chart.
• Cannot measure distance and direction directly.
• True shapes are not represented
What are the characteristics of Planar or Azimuthal Projections?
-Points on the Earth are projected onto a plane, tangent at a single point
-Great Circle Charts
Parallels (except the equator) appear as curves
Meridians appear as straight lines converging toward the nearer pole
What are the advantages and disadvantages of Mercator projections ?
Advantages:
Rhumb lines plot as straight lines
Ease of measurement (distance, direction & position)
Latitude/longitude draw as straight lines
Correct angular relationships
– Disadvantages:
Great circles plot as curves
Distortion of features at extreme latitudes
Difference in plotted distances according to Latitude
What is a Rhumb line?
-A rhumb line is a line on the earth's surface that crosses all meridians at the same angle. It is also known as a loxodrome or spherical helix.
What scales are Paper charts broken up into?
-Sailing
-General
-Coastal
-Harbor
What scales are Digital Nautical charts (DNC) broken up into?
-General
-Approach
-Coastal
-Harbor
A statute mile is how many feet?
5280 ft
1 nautical mile equals how many feet, yards and latitude
-6076 ft
-2025 yds
-1 mind of latitude
How long is a tidal epoch?
-18.6 yrs
The lowest part of the bridge you’re passing under is measured from what?
-Mean high water
Variation is compass error caused by what?
-Earth’s magnetic field
Deviation is a compass error caused by what?
-Ship’s magnetic field due to construction
What are the characteristics of the US Local Notice to Mariners (LNM)?
-Published by USCG Districts (9 total Districts) weekly
-Online or email subscription
-Similar to NTM, but more costal nature
-Information concerning aids to navigation, hazards to navigation, and other items of marine information of interest to mariners on the waters of the of the US, its territories, and possessions
What are the characteristics of the US Notice to Mariners (NTM)?
-Published by NGA weekly
-Online or email subscription
-Provides corrections for unclassified nautical charts
What are the 5 major types of buoys?
-Lateral
-Cardinal
-Safe Water
-Isolated Danger
-Special Purpose / Cautionary
Describe an emergency wreck marking buoy
Temporary response, places as close to wreck as possible
-A pillar o spar buoy
-Yellow and Blue with vertical stripes
-Nominal range of 4 nautical miles
What are the characteristics of lights on lateral marks?
Flashing (FL)-
Quick Flashing (QKFL)
Very quick flashing (VQFL)
Group Flashing
FL- Not more than 30 flashes per minute, flash every 2.5sec, 4sec, or 6 sec
QKFL- 50 flashes per min, 1 flash per second, only on red, green, or yellow buoys
VQFL- 80 flashes per minute, 2 flash per sec
Group- Multiple combinations depending on the application
If lighted what are the characteristics of a bifurcation buoy?
-Composite group flashing (2+1)
-Red over green or green over red
What do Lateral buoys mark?
Lateral buoys mark the sides of a navigational channel as well as junctions, bifurcations, the safe side to pass a hazard, and the centerline of wider fairways and large bodies of water
What do Cardinal buoys mark?
Cardinal buoys mark the directions in which the buoy lies relative to the hazard to navigation
What do Safe Water buoys mark?
Safe water buoys mark safe water on all sides. Outside the US, can mark centerline of traffic separation
-REd and white stripped
-Will show letter NOT numbers
-MILO buoy Morse Alpha, Isophase (2sec on 2 off, Long Flash(on 2 off 8), Occulting(on 8 off 2)
What do Isolated Danger buoys mark?
Isolated danger buoys mark particular hazards to navigation that have water all around it, may be on top of or moored near the hazard
What do Special Purpose/ Cautionary buoys mark?
Special Purpose / Cautionary buoys mark a special area that should be kept clear of.
-Yellow Color
-Top mark is a cross
-If lighted, yellow
Where is IALA B used?
North, Central, and South America, Japan, South Korea, and the Philippines
-Red to RIGHT returning
How is an MRASS buoy activated?
Mariner Radio Activated Sound Signal (MRASS)- They are activated by clicking your VHF radio 5 times on wither 81a or 83a. They will sound from 45mins - 1 hours
How long is a Tidal Day?
24hrs 50mins.
What is a Semidiurnal tide?
Tides have 2 highs and 2 lows per tidal day
When does Slack water occur?
When the horizontal movement of water stops
1 knot of current equals how much wind?
30 kts of wind
How is DSC different from regular traditional VHF radio?
-Allows the user to call a specific vessel using its MMSI
-Provides a button to generate a distress call which contains the vessel's exact position
What does the GMDSS stand for?
Global Maritime Distress and Safety System
What are the following VHF channels used for:
9
13
16
22a
70
87b
88b
9- Boater Calling. Commercial and Non-Commercial
13- Intership navigation safety. ships>20m guard in US waters
16- must guard, intl. distress safety and calling
22a- USCG maritime safety broadcast
70- DSC Channel
87b- AIS
88b- AIS
All vessels of length 2-m or greater are required to guard what VHF channels?
Ch 13
Ch 16
What does VHF-DSC stand for?
Very High Frequency - Digital Selective Calling
What are the primary approved resources of tide and current data for US Navy ships?
-tidesandcurrents.noaa.gov when operating in US waters
-TotalTide operating in international waters
Define the baseline from which tidal heights are measured?
-MHW
-MLW
-MLLW
-MHW- Mean High water, mean of all high waters in a 19 year period (tidal epoch). Datum used to measure bridge clearance
-MLW- The mean of all the low waters in a 19 year period (tidal epoch)
-MLLW- the mean of all the lower of the two low tides in each tidal day over a 19 year period. Primary datum for US charts
What are neap tides?
Tides of less/decreased range and occur when the moon is half
What are Spring tides?
Increased range (higher highs and lower lows. Occur about twice a month and happen because the moon is either New or Full.
-Mean high water springs (MHWS is the mean of all the high spring tides
-Mean Low Water Springs (MLWS) is the mean of all the low spring tides
What are Mixed tides?
Tides with a large inequity between the high and/or low water heights
What is a Diurnal tide?
Tidel has a cycle of one tidal day, there is 1 high tide and 1 low tide per tidal day
What are the characteristics of a Occluded front?
- Purple line w/half diamond and half circle on same side
-Front resulting when a cold front overtakes a warm front, and wedges it aloft
-End up with 3 distinct masses of air
-The weather is nasty and unpredictable
What are the characteristics of a Stationary front?
-They are a cold and warm air mass, lying against each other
-Half circles on one side and triangles on the other side
-They may generate or regenerate into very strong frontal systems, so keep an eye on them
What are the characteristics of a Warm front?
- the leading edge of where a warmer air mass replaces a colder one
-Because warm air is less dense than the cold air it is replacing, in order for a warm front to work, the cold air ahead of it has to be receding. the warm air is lighter and it really can't push the heavier air
-You will Cirrus, then cirrostratus, then altostratus, then nimbostratus, then stratus
-Line with half circles
What are the characteristics of a Cold front?
-The leading edge of a cooler, drier and more stable air mass
-Rapid drop in dew point (air gets dryer)
-May generate squall lines
-Expect squalls and showers preceding the passage of the front
-Blue line with triangles
Which way do do isobars tend to "kink from the lower pressure area?
-A "veering" wind shifts to the right, or clockwise
-A "backing" wind shifts to the left or counter-clockwise
What are the 4 types of fronts?
-Cold Front
-Warm Front
-Occluded Front
-Stationary Front
How long do synoptic weather events last?
Synoptic weather events usually last from a few days to a week or two
What are the global air circulation cells?
Moving North from the Equator (ITCZ) Hadley Cell - Ferrell Cell - and the Polar Cell
What the horse latitudes?
The descending air athe 30's Lat, characterized by high pressure, clear skies, and little wind
What are the characteristics of the ITCZ?
The Intertropical Convergence Zone (ITCZ) or the doldrums.
-Near constant barometric pressure; light and variable surface winds and hot and sultry days.
-Equatorial low pressure trough
-Often see overcast skies and heavy showers and thunderstorms
How do you determine wind direction at the surface by looking at the isobars?
Cross the isobars at a 90 angle going from high to low pressure, then turn about 70 to the right in the Northern Hemisphere (or left in Southern Hemisphere)
What is the Coriolis Effect?
As a result of the earth's rotation, anything moving freely across the surface of the Earth tends to get pulled off to one side
-Northern Hemisphere pulls to the right
-Southern Hemisphere pulls to the left
What are the different types of Fog?
-Radiation fog
-Ground fog
-Advection fog
-Steam fog
-Upslope fog
-Valley fog
What is the most important element in fog formation?
Condensation Nuclei for water to condense upon
Cumulus clouds that have developed into thunderclouds. Huge vertical development, like 50,000 ft sometimes. Thunder, lightning, strong surface winds, torrential rain
Cumulonimbus
Puffy fair weather clouds. Flat base, lots of vertical action. Wind can break up big ones into fractocumulus. These are the clouds that show up over islands at sea, or above landmasses on hot sunny days
Cumulus (Cu)
Clouds that are thick, dark gray shapeless clouds. Rain or snow and lots of it. There are irregular broken clouds beneath and surrounding (fractostratus), they have poorly defined "wet" undersurface unlike the distinct surface of stratus
Nimbostratus (Ns)
What does fracto mean?
Broken up into pieces
What does Nimbo or nimbus?
Rain
What is standard sea level air temperature?
59F
What is dew point?
Dew point is the temperature at which air can no longer hold water vapor
Lines of equal atmospheric pressure are called?
Isobars, Spaced 4mb apart
-The closer the isobars, the steeper the pressure gradient and the stronger the wind
What are the 4 ways that air rises?
-Convection
-Wind Up/Down over a mountain range
-Air may be forced aloft as a result of fronts (cold/hot) meeting
-Air may move vertically (Up or Down) as a result of convergence or divergence
What is standard atmospheric pressure?
-1013.25mb +/- 35mb (normal range)
-29.92” Hg +/- 1.5” (normal range)
-14.7psi
What is Lapse Rate?
-Cooling associated with increased altitude, Usually about 3.6℉ per 1000’
What are the characteristics of the Troposphere?
- Bottom 8 miles (40kft) of atmosphere
-Temperature drops off rapidly as you ascend
-The temperature of the troposphere hovers around that temperature where water evaporates, condenses and freezes
What is the range of AIS?
20-30 miles
True/False Dynamic AIS information updates more as you go faster or make course changes
True
What are the 4 types of information AIS provides?
-Static Information
-Dynamic Information
-Voyage Related Information
-Short Safety Related Messages
What are the operating modes of AIS
-Autonomous and Continuous: most common op mode
-Assigned:
-Polled: shore stations can request specific information form ship stations
How will LCS interact with the SART system?
-VHF Voice Alert
-VHF DSC alert
-show on 3cm wavelength radar
-RCC Notification
What is a SART?
-Search and Rescue Transponder
-8nm effective range
-Will only respond to X-band (3cm wavelength)
How does GMDSS work?
-Global Maritime Distress and Safety System
4 Sea Areas
Area 1 -within VHF range of land
Area 2 - less than 200+nm range
Area 3 -200+nm range
Area 4 -Polar Regions
Voice Signal: Lifeboat - Ground Station/SAR Helo
Digital Signal: EPIRB - COSPAS Satellite systems - Coastguard ground Control Station - transmitter - Inmarsat satellite - ships at sea (for USN ships direct contact from NFC or HYDROLANT/HYDROPAC or Daily Memorandum)
What is the dry adiabatic lapse rate?
5.5 F per 1000 feet of altitude
Large, heavy rolls or blobby masses, in long, ray parallel bands. Cover most of the sky
Stratocumulus (Sc)
What is the saturated adiabatic lapse rate?
3.2 F per 1000 feet
Uniform gray sheet or layer. No particular form or shape, usually cover the sky. Thicker and darker than the higher Altostratus. If it gets low enough, its fog
Stratus (St)
Elliptical globs in groups or individually. When in groups, they may for loose bunches or distinct bands. Maybe gray shading underneath. Sometime elliptical shaped, unlike regular cumulus
Altocumulus (Ac)
Cloud with Uniform bluish or gray-white sheets. Sun may be totally obscured or shine through weakly. Yields a large amount of precipitation
Altostratus (As)
Small white flaky puffs. Mayb cover the sky withbands, little or no shading. "Mackerel Sky"
Cirrocumulus (Cc)
Thin whitish veil of high clouds?
Cirrostratus (Cs)
Which clouds are the highest, light wispy feathery clouds, "Mare's tails", delicate patches?
Cirrus (Ci)
What type of air is fuel for storms?
Warm humid air is fuel for storms
What are extra-tropical Cyclones/extra-tropical frontal waves or Mid-Latitude Cyclones?
-Have cold core
-They form along the jet stream
-They have a life cycle of several days to over a week
-They have length scales of the order of 500–2500 km
-They have cold air at their core
-They derive their energy from the release of potential energy when cold and warm air masses interact
-They always have one or more fronts connected to them
When do you feel shallow water effects?
Less than 2.5x draft of the ship
Kedging
Dredging
Snubbing
Baltic Moor
Med Moor
Kedging-Poor mans tug, put anchor down away from pier and use it to pull the bow
Dredging- Anchor under foot 1.5x depth as ship moves slowly to increase the turning lever by moving the pivot point
Snubbing- like battle ship
Baltic Moor- let go anchor while parallel to pier, dredging to the pier
Med Moor
What is momentum?
the quality of motion measured by the product of mass & velocity
What is inertia?
Inertia is the quality of motion that causes a ship to resist a change in motion
What are the 4 basic functions you able to do on any ARPA?
-Acquire
-Designate
-Perform Trial Maneuver
-Cancel contacts
How much steady tracking does ARPA before displaying 95% accuracy?
Requires 1-3 mins
IMO performance standards for ARPA are intended for vessels of what GT?
Intended for vessels over 10,000 GT
What does ARPA stand for?
Automatic radar Plotting Aid
What is FTC?
Fast Time Constant
-As you turn it up, it decreases the sensitivity of the receiver at the far edges of a contact, be it a rainstorm, or land, or a ship
What is STC?
-STC: Sensitivity Time Control
- As you turn it up, it decreases radar sensitivity near the center of the screen, gradually increasing as you move outward
What are radar unwanted echoes?
-Indirect
-Multiple echos
-Second trace echoes
-Radar Interference
What is the relationship between radar antenna and horizontal beam width?
The wider the antenna, the narrower the horizontal beam width
What determines a radar's minimum range?
Length of the radar pulse
What is the primary determinant in range resolution and range accuracy?
Pulse length
Short vs Longer radar pulse
Short pulse- give crisp, clearly defined presentation, but don't do well on long ranges
Long pulse- great for detecting small weak contacts at long range, but don't paint a very crisp picture
What's the frequency of the energy in 10cm radar?
10cm / S band / 2,000 MHz
What's the frequency of the energy in 3cm radar?
3cm / X band / 10,000MHz
Parts of surface radar system?
Transmitter
Receiver: TR check valve keeps power from transmitter from damaging
Power Supply
Modulator
Indicator
What is super-refraction?
Also called inversion
REsults in maximum radar range
Increased downward bending of the waves as they travel through the atmosphere along the surface of the earth
What is refraction?
Where waves change direction as they pass from a medium of one density into a medium with a different density
What is reflection?
Where waves change direction when they bounce off a barrier
True/False. Radar energy bends toward denser medium
True
What do we use microwave energy for radar?
-Reflects off metal surfaces
-Can be directed through metal waveguides
What is the Speed of Light?
328yds/micro sec
162,000nm / sec
.162nm / micro sec
What is significant wave height?
The average of the highest one third of the waves
What are our options to deal with bad seas?
-Slow down
-Change course
-Combination of slowing and changing course
-Stay in port
What are the four basic types of seas?
Head Seas- Bad for Ship
Beam Seas- Bad for people
Quartering Seas
Following Seas
What is the goal of operational Guidance & Safe Operating Envelopes?
-Provide the maximum operational flexibility for the ship while maintaining an acceptable level of safety for the ship and is crew
What radar on LCS can be used to locate weather?
3cm Radar X-band
How does the classify Sea State?
Pierson-Moskowitz Sea Spectrum
How are winds speeds classified?
The Beaufort Scale is how wind speeds are classified
How are tornedos measured?
Enhanced Fujita Scale
What are the ingredients for a tornado?
Mix warm, moist air with cooler, drier air
What is the most intense type of local squall?
Macro/Microbursts the most intense type of local squall
What are the three stages of air mass thunderstorms?
-Cumulus: Lots of updrafts, enough to keep all precipitation aloft
-Mature: Most violent and active stage
-Dissipating: During this stage, subsiding air replaces the updraft throughout the cloud
What is the most common type of thunderstorm?
Air Mass thunderstorm- which form as part of a single convective cell over hot land or water (Gulf Stream)
What three things do Thunderstorms require for their formation?
-Moisture
-Instability
-Lifting Mechanism
What is an anti-cyclone?
An anticyclone is a weather phenomenon that occurs when winds circulate around a center of high atmospheric pressure.
- Clockwise in Northern Hemisphere
-Move west to east, 20 to 30 mph
What is Buys-ballot's law?
(Northern Hemisphere) Face away from the wind, the low will be 270 relative over your left.
-"Back to the Breeze, Low to Your Left"
-Dangerous Semi-Circle wind on STBD bow
-Navigable Semi-Circle wind of STBD QTR
What are the characteristics of Tropical Cyclone, Hurricane, Cyclone, or Typhoon?
-Have warm core
-Tropical cyclones get their energy from the warm ocean
-Atlantic hurricanes form off the coast of Western Africa above the hot ocean waters just north of the equator
-Sea Surface Temperature above 78F
-Pre-existing disturbance to trigger thunderstorm activity
-Divergence at the upper levels (above 400mb about 24k+ft)
-Coriolis Force will generally be sufficient at latitudes poleward of 5 degrees North/South
-Weak (Less than 20kts) vertical wind shear between the surface and upper troposphere
-Relatively moist layers at the mid-levels (about the 700mb / 10,000 ft)
-System embedded in a potentially unstable air mass
How much HP do Escort/Salvage ships typically have?