IMPORTANT CHAACTERISTICS OF A RADAR

1) VERTICAL BEAMWIDTH (VBW):

IT IS THE VERTICAL ANGLE AT THE SCANNER CONTAINED BETWEEN THE UPPER &THE LOWER EDGES  OF THE RADAR SETS BEAM.AS PER THE IMO STANDARDS THE RADAR SET SHOULD FUNCTION IF THE VESSEL IS ROLLING OR PITCHING +_10 DEG WITHOUT DETERIOATION.

MARINE SETS HAVE A VBW OF 15-30 DEG.

2)      HORIZONTAL BEAM WIDTH (HBW):

IT IS THE HORIZONTAL ANGLE AT THE SCANNER CONTAINED  BETWEEN THE LEADING & THE TRAILING EDGE OF THE RADAR BEAM .IT CAUSES ALL THE TARGETS TO APPEAR LARGER IN AZIMUTH  BY AN AMOUNT  EQUAL TO HLF THE HBW.

3)      PULSE LENGTH:

DUE TO THE PULSE LENGTH THE POINT OF THE PPI APPEARS TO HAVE A RADIAL DEPTH OF HALF PL IN METERS.IT IS THE TIME INTERVAL BETWEEN THE TIME TAKEN BY THE PULSE TO LEAVE 5HE LEADING AND THE TRAILING EGDES.

4)      PULSE REPITION FREQUENCY/(PRF):

IT IS THE NUMBER OF PULSES SET OUT THROUGH THE SCANNER IN ONE SECOND. IT ISBETWEEN 500-4000.LONGER RANGES HAVE LOW PRF.SHORTER RANGES NEED HIGH PRF FOR BETTER PICTURE  RESOLUTION.

5)      WAVELENGTH:

AFTER RADAR ENERGY  LEFT  THE SCANNER THE PATH ENERGY &TRABEL ARE INFLUENCED  BY :1)ATTENUATION,      2)DIFFRACTION.

X BAND:  3CM WAVELENGTH.(9300-9500 MEGS)

S BAND :10 CMS WAVELENGTH.(2900-3100 MEGS)

3CM :GREATER ATTENUATION ,LESS DIFFERENCE ,GOOD FOR SHORT RANGES.

10 CM: LESS ATTENUATION, MORE DIFFERENCE,GOOD FOR LONGER RANGES.

                           LIMITATIONS OF RADAR SET.

1)RANGE DISCRIMINATION:

IT OIS THE ABILITY OF THE RADAR SET TO CLARLY DISTINGUISH TWO SMALL TARGETS ON THE SAME BEARING AT SLIGHTLY DIFFERENT RANGES.

THE DISTANCE BETWEEN THE TWO TARGETS IS EQUAL TO OR LESS THAN 1/.2 PL.

2)BEARING DISCRIMINATION :IT IS THE ABILITY OF THE RAAR SET TO CLEARLY EXTINGUISH TWO TARGETS OF THE SAME RANGE AND SLIGHTLY DIFFERENT BEARINGS.FACTOR:HBW.

3)MINIMUM RANGE:

A)    THE PULSE LENGTH :THE TR CIRCUIT PREVENTS THE TX OF ANY SIGNAL BEFORE RECEIVING IT.HENCE,THE THEOROTICAL MINIMUM RANGE OF DETECTION IS REPEATED BY HALF PL IN MINUTES.

A PL OF 0.2 MICRO  WOULD HAVE ARANGE OF 30 MTRS.

B)    DEIONISATION DELAY:  A SMALL DELAY OCCURS IN THE TR CELL BETWEEN THE COMPLETION OF TX &RECEIVING. A DELAY OF 0.5 MICROSECS.WOULD INCREASE  THE MINIMUM RANGE A FURTHER BY 7.5 MTRS.

C)THE VBW +THE HEIGJHT  OF THE SCANNER.

4)MAXIMUM RANGE:

A)HEIGTH OF THE SCANNER INCREASES  THE SCANNER , THE INCREASE OF RANGE.

 B) POWER OF THE SET ,MARINE RADAR SET TRANSMITS AROUUND 25 TO 60 KWTS.

C)    WAVELENGTH     : 10 CMS HAVE EXTENDED RANGE AS COMPARED TO 3 CMS.

D)    PULSE REPETION FREQUENCY:

E)     PULSE LENGTH: LONG PULSES ENSURES BETTER MAXIMUM RANGES THAN SHORTER PULSES  CAUSE ,LONG PULSES  HAVE MORE WAVELENGTH IN THEM.

F)     VBW/HBW:THE NARROWER THE BEAM WIDTH THE GREATER THE DIRECTIONAL CONCENTRATION,INCREASES THE RANGE.

6)      ANOMALOUS PROPOGATION:  SUPER REFRACTION CAUSES AN INCREASE IN MAXIMUM DETECTION RANGE. THIS IS CAUSED DUE TO  METEOROLOGICAL FACTORS LIKE TEMPERATURE INVERSION.

RANGE ACCURACY: ACCORDING TO IMO PERFORMANCE STANDARDS THE ERROR IN THE RANGE OF AN OBJECT SHOULD NOT BE MORE THAN 1.5% OF THE MAXIMUM RANGE SCALE IN USE OR 70 MTS WHICHEVER IS THE GREATER.

BEARING ACCURACY: ACCORDING TO THE IMO PERFORMANCE STANDARDS THE OBJECT SHOULD BE MEASURED WITH +_ 1 DEGREE OF ACCURACY.

THE FOLLOWING ARE THE MERITS/DEMERITS OF USING HEADS UP MODE / NORTH UP MODE:

HEADS UP DISPLAY:

1)          PICTURE SMUDGES IN AZIMUTH DURING ALTERATION OF COURSE.

2)           BECAUSE OF SMUDGING ACCURATE BEARINGS CANNOT BE TAKEN AT THAT TIME.

3)           PLOTTING TENDS TO BE HIGHLY INACCURATE DURING SEVERE YAWS.

4)           ALL BEARINGS ARE RELATIVE.

5)           RADAR PICTURE IS HEAD UP WHILE CHART IS NORTH UP.

6)           AFTER LARGE ALTERATIONS OF COURSE THE OBSERVER TENDS TO GET DIS- ORIENTED WITH PLOTTING AS ALL TARGETS HAVE SHIFTED.

7)           NO INDICATION ON THE SCREEN OF GYRO COURSE STEERED.TEMPORARY WANDERINGS MAY GO UNDETECTED.

NORTH UP DISPLAY:

1)          PICTURE DOESN’T SMUDGE IN AZIMUTH AND BEARINGS CAN BE TAKEN ACCURATELY.

2)           PLOTTING IS QUITE ACCURATE EVEN DURING HEAVY YAWS.

3)           ALL BEARINGS ARE TRUE.

4)           CHART AND PPI. BEING NORTH UP IT IS EASIER TO RELATE.

5)           THERE IS NO DISORIENTATION DUE TO ATERATION OF COURSE.

6)           HEADING MARKER INDICATES THE GYRO COURSE STEERED AT ALL TIMES.

DRAWING FORWARD: IT IS THE VESSELS RELATIVE POSITION APPROACHING THE SHIPS HEAD. IT CAN ALSO DRAW AFT.

EG.  IF THE RELATIVE BEARING OF THE TARGET CHANGES FROM 090 TO 085 THE TARGET IS SAID TO BEAR FORWARD.

ASPECT:  THE ASPECT OF THE VESSEL IS THE ANGLE BETWEEN THE VESSELS TRUE COURSE AND THAT OF THE REVERSE BEARING TO THAT VESSEL. ASPECT IS EXPRESSED IN RED OR GREEN FROM 0—180 DEG.

EG.  ASPECT RED 90 MEANS THAT WE ARE ON THE VESSELS PORT BEAM.    

ISM CODE - SYNOPSIS

Adoption  of  chapter  IX   SOLAS

PURPOSE   OF   THE   CODE

                            Is to provide an international standard for the safe management and operation of ships and for pollution prevention.

                              It became mandatory on the 1^st July 1998, for all vessels including High Speed Crafts etc. above 500 GRT. All ships and mobile offshore drilling units are requires to comply not later than 1^st July 2002. Ships less than 400 GRT may comply voluntarily. The IMO (International Maritime Organization) accepted an assembly where by all governments should safe guard the Master on the proper discharge of his responsibilities with regard to safety & protection to the marine environment. It also adopted a policy where by a shore based personnel who is an elected member of the company to respond to the needs of personnel on board ship so that high standards of safety and environmental protection is maintained.

GENERAL OBJECTIVES FO THE CODE

1.      To ensure safety at sea.

2.      Prevention of human injury  & loss of life.

3.      Avoidance of damage to the environment in particular to the marine environment and to the property.

OBJECTIVES OF THE SAFTETY MANAGEMENT OF THE COMPANY

1.      Provide for the safe practices for the ship operation and safe working environment.

2.      Establish safe guard against all identified dangers.

3.      Continuously improve safety management skills of personnel ashore and aboard.

The company should adopt a safety and environmental policy and make sure that it is being followed by both ship based as well as shore based personnels to ensure high standard of safety & environmental protection.

If the owner is not the one who is responsible for the working of the ship he should hand over the persons name responsible for the working of the ship to the ISM administration. the company should define duties of various persons on board ship and make sure that they are being carried out regularly and in a systematic fashion. The person designated by the company at shore should have direct access to the highest management level (known as Designated Person) and his duties are being carried out from time to time with regard to the safety of life and the prevention of pollution to the marine environment. The master should see that the policy implemented by the company is being followed strictly on board ships, perform his duties with regard to motivation of crew to observe the policy, issue orders in simple language and in case of any deficiency and requirement on board should point it out to the company without hesitation. The company in its document should make sure that the Master is the head of all operations and his word is final, but before doing so the company should make sure that the master is a well qualified person and capable of carrying out his duties in highly sophisticated manner.

Emergency drills should be planned by the company, which should practice on board ships so in case of emergency the crew will be able to respond to their duties efficiently. Finally company should arrange for internal audits to make sure that the Safe Management System is being followed and every means to ensure safety of life & prevention of pollution to marine environment is taken.

 

 

CERTIFICATION

The ship should be operated by the company which is issued a  Document Of Compliance (DOC) relevant to that ship.

The DOC should be issued to every company complying with the requirement of the ISM code by the administration

A copy is kept on board with the master, if so asked may produce it for certification of the administration or organizations received by it and a SMC should be issued to the ship by the ISM administration after making sure that the ship & the company operate in accordance with the approved SMS.

1.      Government authorized organization to issue a DOC to company, copy of this DOC to be on vessel.

2.      The DOC is issued after verification by authority that SMS is functional in view of documentation + audit reports for atleast 3 months.

3.      DOC  +  SMC’s are valid for 5 years subject to annual verification 3 months +  the anniversary date +  1 intermediate verification  for the SMC.

4.      Interim DOC valid for 12 months, SMC for 6 months.

TERMS

·         Non-Conformity:               deviation from requirements specified in the SMC’s.

·         Major Non-Conformity:   is the one that poses a serious threat to life, vessel or    environment.                         

·         NCR:                                   Non- Conformity Reporting.

·         CAR:                                    Corrective Action Requests.