Classified Name• 1A1-OIL REC-HELI DK (SHF)-FIFI-DYNPOS AUTS-Eo-SF-CRANE-ICS.• 1A1 - Vessel for which periodical surveys are stipulated in relation to special (main)periodical survey intervals of 5 years.• OILREC - Vessel for occasional handling, storage and transportation of oil with flashpoint below 60ºC recovered from a spill of oil in emergency situations.• HELIDK-Helicopter Deck.• DYNPOS Vessel with dynamic positioning systems• E0 - Machinery of craft fitted with instrumentation and automation equipment• SF - Implies classification of stability and floatability• CRANE - Vessel with permanent cranes, when lifting operations are not a mainpurpose.• ICS - Integrated computer system.
Principle of RADAR• The radar transmitter produces short duration high-power RF- pulses of energy.• The duplexer alternately switches the antenna between the transmitter and receiver so thatonly one antenna need be used. This switching is necessary because the high-power pulsesof the transmitter would destroy the receiver if energy were allowed to enter the receiver.• The transmitted pulses are radiated into space by the antenna as an electromagnetic wave.• The antenna receives the back scattered echo signals.• The hypersensitive receiver amplifies and demodulates the received RF-signals.
Pulse repeatation Time:The time between thebeginning of one pulse andthe start of the next pulse iscalled pulse-repetition time(PRT).The Pulse RepetitionFrequency (PRF) of theradar system is the number ofpulses that are transmittedper second. They both areinversely propotional
Problem with pulsed radar• Maximum unambiguous range.: This problem is sortedout by increasing the pulse repeatation time.Radar waveform minimum rangeWhere Is the Pulse width.A typical value of 1 µs for the pulse width of short range radar corresponds toa minimum range of about 150 m.
RutterThe rotation speed is24rpm for X band radar.26 rpm for S band.
EPIRB• Emergency Position Indicating Radio Beacon.• A 5-Watt Radio Tran-mitter operating at406MHz.
Navtex System• For navigation purposes, the world is divided into 16 areas.• Each Navtex station has an identification code, from “A” to “Z”.• The frequency assigned to Navtex are 518 kHz and another (490 or 4209.5 kHz), andmany stations exist in the same service coverage.• For automatic identification of messages, each message starts with nine control• characters, called “Header codes”.• The first five characters are always “ZCZC_“ and common to all messages.• This part is used for message synchronization. The latter four characters aredesigned as B1, B2, B3 and B4 indicate origin, category and serial number of themessage.• Character B1 is the identification letter of the Navtex station “A” thru “Z”.• Character B2 indicates the type of message. “A” thru “Z”, as listed below.• Character B3 and B4 indicate the serial number of the message. The serial• numbers are counted up from “01” to “99”, and starts from “01” again.• The end of each message is indicated by “NNNN”.