Communications

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Communications

• Ordinary Requirement 10

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Ordinary Requirement 10

• Name the three principal methods of visual
  signaling and explain the advantages and
  limitations of each method.
• Name the three principal types of radiotelephone
  equipment in marine use and demonstrate your
  knowledge of correct radiotelephone procedures.
• Reference See Communications Signaling p. 222
  and Radiotelephone Procedures on p. 200

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Communications Signaling

• Signaling is carried out in several ways at sea.
• Some devices used are
• International Code Flags
• Signal Flags (semaphore)
• Blinker lights (Morse code)

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International Code Flags

• International code flags are used to signal
  between two ships or between ship and shore.
• Also called signaling flags, they are a set of
  flags of different colors, shapes and markings
  which used singly or in combination have
  different meanings.
• A set of flags consists of 26 flags for the
  letters of the alphabet, ten number pennants,
  three substitute pennants, and the answering
  pennant.
• (The U.S. Navy uses a fourth substitute and calls
  them all "repeaters.")
• The substitutes are necessary because a set
  contains only one flag for each letter and some
  flag hoists require repetitions of one or more
  letters.

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International Code Flags

• Five standard colors are used red, white, blue,
  yellow, and black.
• Only a few colors can be readily distinguished at
  sea.
• Most of the flags are of two colors, selected and
  arranged for maximum contrast.
• Two flags are of a single color only, three use
  three colors, and one uses four colors.
• For clarity, the flags are either red and white,
  yellow and blue, blue and white, or black and
  white or plain red, white, and blue.
• Flag hoists are read from the top flag or pennant
  downward
• if there is more than one hoist from a single
  spreader or yardarm, each hoist is read in turn
  from outermost inward.

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International Code Flags
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International Code Flags

• One-flag signals are urgent or very common
  signals.
• Two-flag signals are mostly distress and
  maneuvering signals.
• Three-flag signals are for points of the compass,
  relative bearings, standard times, verbs,
  punctuation, also general code and decode
  signals.
• Four-flags are used for geographical signals,
  names of ships, bearings, etc.
• Five-flag signals are those relating to time and
  position.
• Six-flag signals are used when necessary to
  indicate north or south or east or west in
  latitude and longitude signals.
• Seven-flag signals are for longitude signals
  containing more than one hundred degrees.

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Flag Hoists

• A hoist consists of one or more groups displayed
  from a single halyard.
• A hoist or signal is said to be at the dip when
  it is hoisted about half of the full extent of
  the halyards.
• A hoist or signal is said to be close up or
  two-blocked when it is hoisted to the full extent
  of the halyards.
• A tackline is a length of halyard about 2 m (6
  ft.) long, used to separate each group of flags.

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Flag Hoists

• Only one hoist should be shown at a time.
• When more groups than one are shown on the same
  halyard they must be separated by a tackline.
• Each hoist or group of hoists should be kept
  flying until it has been answered by the
  receiving station.
• The transmitting station should always hoist the
  signal where it can be most easily seen by the
  receiving station.

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How to Signal

• How to call
• The identity signal of the station addressed is
  to be hoisted with the signal.
• If no identity signal is hoisted it will be
  understood that the signal is addressed to all
  stations within visual signaling distance.
• How to answer signals
• All stations to which signals are addressed hoist
  the answering pennant at the dip as soon as they
  see each hoist and close up when they understand
  it
• The answering pennant is to be lowered to the dip
  as soon as the hoist is hauled down at the
  transmitting station, being hoisted close up
  again as soon as the next hoist is understood.

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How to Signal

• How to complete a signal
• The transmitting station is to hoist the
  answering pennant singly after the last hoist of
  the signal to indicate that the signal is
  completed.
• The receiving station is to answer this in a
  similar manner to all other hoists.
• How to act when signals are not understood
• If the receiving station cannot clearly
  distinguish the signal made to it, it is to keep
  the answering pennant at the dip.
• If it can distinguish the signal but cannot
  understand the meaning of it, it can hoist the
  following signals
• ZQ Your signal appears incorrectly coded.
  You should check and repeat the whole,
• ZL Your signal has been received but not
  understood.

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Substitutes

• Substitutes enable the same signal flag to be
  repeated one or more times in the same group,.
• The first substitute always repeats the uppermost
  signal flag of that class of flags which
  immediately precedes the substitute.
• The second substitute always repeats the second
  and the third substitute repeats the third signal
  flag, counting from the top of that class of
  flags which immediately precedes them.
• No substitute can ever be used more than once in
  the same group.
• The answering pennant when used as a decimal
  point is to be disregarded in determining which
  substitute to use.

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Substitutes

• For example, the signal V V would be made as
  follows V first substitute
• The number 1100 would be made by numeral
  pennants as follows 1 first substitute 0 thir
  d substitute
• The signal L 2330 would be made as
  follows L 2 3 second substitute 0
• In this case, the second substitute follows a
  numeral pennant and therefore it can only repeat
  the second numeral in the group.

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Semaphore

• One of the most commonly used methods of visual
  communications is semaphore. 
• Widely used, especially in the navy, before radio
  and telegraph systems were invented.
• Semaphore uses the position of the arms to code
  letters and numbers.
• The signalman sends messages letter by letter by
  holding the two flags in various positions
  similar to the hands of a clock.
• Sometimes a wooden board was used with "arms" in
  the correct position.
• Note that it is the position that matters - it is
  irrelevant which arm is used, although for some
  letters it is much easier to use the right arm
  and so the left is seldom used, but would be
  equally correct if you wished to use it.

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Semaphore
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Sending Semaphore

• Hold each flag so that the staff is a
  continuation of your forearm and keep your arms
  stiff.
• Whenever you cross a flag in front of you to make
  a letter, twist your body slightly in the same
  direction.
• Get the receiver's attention with the Attention
  signal, made by waving both flags repeatedly
  overhead in a scissor-like motion.
• When the receiver sends the letter K, you can go
  ahead.
• Send the letters of each word by going directly
  from the position of one letter, without
  stopping, into the position of the next, pausing
  in each.
• If you have to think of the next letter, hold the
  letter you are making until the next one comes to
  mind.
• Indicate the end of a word with the front signal
  by bringing the flags down in front of you, with
  the staffs crossing.

• Whenever double letters appear in a word, use the
  front signal to separate them.
• Make the first letter, then front, and
  immediately, without pause, bring the flags again
  in position of the letter.
• The receiver acknowledges each word by sending C.
• If he or she suddenly sends I-M-I, it means that
  he or she did not catch your last word. Repeat it
  and continue from there.
• If you have made an error yourself, send eight Es
  and start again from the beginning of that word.
• Finish the message with A-R and wait for the
  receiver to make the letter R.
• This means the receiver has your message.

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The International Morse Code

• Morse code was the standard signaling means
• Naval Deck officers were trained until the 1980s
• Can send by different methods
• Blinking light, flashlight, covered lantern,
  porthole, ships light
• Electric buzzer, ships whistle, siren or fog
  horn
• Signal flag (when held for a long interval for
  dashes and short interval for dots)

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Morse Code
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Signaling Advantages

• Semaphore signals can be sent and received much
  more quickly than flag hoists or even flashing
  light using Morse code. 
• But can be used only in the daytime and at short
  distances.
• A semaphore flag used singly can also be used for
  "wig-wag" signaling of Morse Code by waving the
  flag to the right or left
• invented by the U.S. Army Signal Corps' Albert J.
  Myer in the mid-19th century.
• Flag hoist signals have the advantage
• of being visible at a greater distance,
• of allowing several messages to be conveyed at
  once on multiple halyards,
• of allowing you to keep them flying for extended
  periods,
• of providing a means of synchronization of action
  based on when they are hoisted, kept at the dip,
  closed full up (two-blocked), or hauled down. 

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Radiocommunication Devices

• A VHF marine radio is the single most important
  radio system you should have. 
• It is probably also the most inexpensive.
• If you plan to travel more than a few miles
  offshore, plan to purchase
• an MF/HF radiotelephone or mobile satellite
  telephone,
• an emergency position indicating radio beacon, or
  EPIRB,
• a second VHF radio or cellular telephone as well.
  
• Mobile satellite telephones are becoming more
  common and more inexpensive.
• The mobile satellite will provide easier and
  clearer communications than the MF/HF
  radiotelephone
• but the HF radiotelephone will receive high seas
  marine weather warnings.

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VHF Radio

• There are 104 VHF channels designated for marine
  service.
• Of this number, 54 are designated exclusively for
  use in the waters of the United States.
• Brevity is important
• If your conversation on Channel 16 is longer than
  30 seconds the Coast Guard will break in to tell
  you to switch to another channel.
• Not to be used for gossip and idle conversation.
• Anything said over the radio will be heard by
  hundreds of other people.
• Only a limited number of channels so conversation
  should be kept to passing only required
  information.
• Conversation is not permitted to extend past
  three minutes. 
• The use of profanity and obscene language is
  illegal.

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Radio Regulations

• Most recreational vessels under 65.6ft/20m in
  length do not have to carry a marine radio.
• Vessels which voluntarily carry a radio, must
  maintain a watch on channel 16 (156.800 MHz) or
  alternatively maintain a watch on VHF channel 9
  (156.450 MHz)
• Any vessel that carries a marine radio must
  follow the rules of the Federal Communications
  Commission (FCC).

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Radio Licenses

• The FCC does not require operators of
  recreational vessels to carry a radio or to have
  an individual license to operate VHF marine
  radios (with or without digital selective calling
  capability), EPlRB, or any type of radar.
• Operators must however follow the procedures and
  courtesies that are required of licensed
  operators specified in FCC Rules.
• You may use the name or registration number of
  your vessel to identify your ship station.
• Users of VHF marine radio equipped with digital
  selective calling will need to obtain a maritime
  mobile service identity (MMSI) number from the
  FCC.

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Vessels Required To Be Licensed

• Vessels that use MF/HF single side-band radio,
  satellite communications, or telegraphy,
• Power Driven vessels over 65.6 feet/20 meters in
  length.
• Vessels used for commercial purposes including
• Vessels documented for commercial use, including
  commercial fishing vessels.
• CG inspected vessels carrying more than 6
  passengers.
• Towboats more than 25.7 feet/7.8 meters in
  length.
• Vessels of more than 100 tons certified to carry
  at least 1 passenger.
• Cargo ships over 300 tons.
• Any vessel, including a recreational vessel, on
  an international voyage.

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VHF Marine Radio Channels
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VHF Radio Usage

• Roger
• Means only that "I understand your transmission."
  It does not mean that I agree or disagree with
  what you said.
• Wilco
• Means "I understand your transmission and I will
  comply with your request." (WIL will, CO
  comply)
• In spite of what you may have heard in old war
  movies, there is no such thing as "Roger Wilco"!
  It is either one or the other, but not both.
• Affirmative
• Means "Yes".
• Do not use words like "Yup" orAlrighty".

• Negative
• Means "No".
• Do not say "Negatory" there is no such word.
• Over
• Means "I have completed my statement and am
  awaiting your reply."
• Just say "Over", not "Do you copy?" or "Come on
  back!".
• Out
• Means that "I have completed my communication and
  I am returning to the hailing channel."
• There is no such thing as "Over and Out". Its
  either one (Over) or the other (Out).

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Non-Emergency Call Procedures

• First listen to your radio to make sure that no
  one else is using the channel.
• Next, you say, Venture, Venture, Venture (repeat
  the name of the boat you are trying to reach)
  this is Gremlin (use the name of your boat)
  over".
• The entire transmission, including a second call
  if necessary, should not take more than thirty
  (30)seconds. If Venture does not answer, you must
  wait two (2) minutes before trying to call him
  again.
• If Venture hears your hail (call), it should then
  go like this
• Venture says, "This is Venture, switch and answer
  on 68".
• (See the correct numbers of all legal working
  channels.)
• Your reply should be, "Roger Venture, 68".
• "Roger" means "I understand", and 68" means "I
  am switching to channel 68 to talk to you."
• After you have finished your transmission/conversa
  tion, say "Out".
• Finally, to conclude the transmission you say,
  "This is Gremlin (your boat) back to channel 16."

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VHF Emergency Calls

• Mayday - Distress Signal
• Is a request for immediate assistance.
• LISTEN! DO NOT TRANSMIT!
• Determine if you're in a position to help. If
  not, maintain radio silence. "Mayday" identifies
  an imminent, life-threatening emergency.
• Pan-Pan - Urgency Signal (pronounced pahn-pahn)
• Is used when the safety of a boat or person is in
  jeopardy.
• Man-overboard messages are sent with the Pan-Pan
  signal
• Running out of gas is not a Pan-Pan situation,
  unless you are in danger of being swept ashore in
  high seas.
• Securite - Safety Signal (pronounced
  say-cure-e-tay)
• Is used to pass navigation information or weather
  warnings. 
• False Distress Alerts
• It is unlawful to intentionally transmit a false
  distress alert, or to unintentionally transmit a
  false distress alert without taking steps to
  cancel that alert.

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Emergency Call Procedures

• Make sure radio is on
• Select channel 16
• Press/hold the transmit button and clearly say
• MAYDAY MAYDAY MAYDAY
• Give
• Name of boat (3 times), call letters or
  description
• Position and/or description of location
• Nature of emergency and kind of assistance
  required
• Number of people on board and condition of
  injured
• Release transmit button
• Wait for 10 seconds If no response, repeat.