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Permit to work – Enclosed space entry

Following are the contents – Enclosed space entry.

  • On the top is the serial number.
  • Date and time
  • How long the permit is valid.
  • Location of work.
  • A total number of persons entering a space with the name and their sign.
  • Information about the work for which the entry is made.
  • The oxygen content of the enclosed space with time.
  • Time of entry and time of exit.
  • Is the space being continuously ventilated?
  • Is the agreed communication system functioning?
  • Is there constant atmosphere monitoring done?
  • Is there a man standing by at the entrance (standby).
  • Is the entrance clear?
  • Is fire fighting equipment available.?
  • Have potential Hazards been identified?
  • Is the bridge and engine room informed?

There are many case when people bypass this checklist and lose life. In fact, I have heard from many of my friends that checklists are being bypassed. Not because the company is putting pressure to do something but people want to show that they did many works this month. This can take your life, So Always follow the checklist even if some top-level officers ask you to skip it.

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Safety ORAL (FUNCTION 3)

Following are the oral questions that you must know before you go for your mates. Click on the question to get an answer (We are working on the answers). What we provide is a sample answer we cannot claim that our answer will be the best answer.

  1. The requirement of Liferaft as per SOLAS?
  2. The requirement of lifeboat as per SOLAS?
  3. In Which Chapter of SOLAS we can find about LIFEBOAT and LIFE RAFT.
  4. What are the equipment in LIFE RAFT?
  5. What are the equipment in LIFEBOAT?
  6. What are the maintenance in life raft as per SOLAS?
  7. What is a RESCUE boat?
  8. The requirement for a Rescue boat?
  9. What is the difference between rescue and Survival craft?
  10. MLC 2006?
  11. Latest STCW Amendments?
  12. Where can you find hydrostatic particular of a vessel?
  13. What is TPA?
  14. What is an immersion suit?
  15. Requirement for muster list and How will you make a muster list?
  16. What is LTA.
  17. Tell me about Rocket Parachute.
  18. Weekly and monthly check for liferaft and life boat.
  19. What is SCBA set?
  20. Parts of SCBA set?
  21. Tests of SCBA set?
  22. What is HRU?
  23. Why we use HRU?
  24. Action if you see fire as a 3rd officer?
  25. How will you engage in Emergency steering?
  26. Content of SOLAS?
  27. What is Intact stability?
  28. What is MOB marker?
  29. Regulations of MOB marker?
  30. What is Lifebuoy?
  31. Requirements of life buoy?
  32. Diff types of life boat?
  33. What is Fire wallet?
  34. Content of fire wallet?
  35. ISPS code ?
  36. Diff between convention and code?
  37. What is the frequency of lifeboat drill?
  38. Frequency of fire drill?
  39. Frequency of enclosed space drill?
  40. Who is SSO ? What are his duties?
  41. Who is DPA and what are his duties?
  42. What is solas training manual where can it be found onboard?
  43. What are heeling tanks ?
  44. What is SART?
  45. What is EPIRB?
  46. Pyrotechnics number and types?
  47. What is LSA code?
  48. Who is the classification society?
  49. Name conventions of IMO
  50. minimum length of hose as per SOLAS?
  51. What is Damage Stablity?
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What is the difference between List and Trim.

LIST is defined as transverse inclination of vessel due to weight of cargo on ship( generally uneven distribution of cargo in ship’s cargo hold) either direction. This is transverse inclination of the vessel. Whereas TRIM is the transverse inclination of the vessel due to wind, Current and other natural factors.

Note- In interview sometime they can ask by showing a image if it is a trim or list, Be confident and tell them its not possible to tell without knowing if the cargo is loaded uneven or if the weather is the factor even if in a image you see a bad weather in the image you cannot assume that cargo is distributed evenly.

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List of cargoes which generate heat, gases and moisture:

  1. Wood, paper pulp and agricultural products may result in rapid and severe oxygen depletion and formation of carbon dioxide.
  2. The IMSBC code lists the following cargoes as potentially oxygen depleting: coal, direct reduced iron, sponge iron, sulphide concentrates, ammonium nitrate based fertilisers, linted cotton seed. Various gaseous products are formed including carbon monoxide, carbon dioxide, hydrogen sulphide and hydro carbons.
  3. Some cargoes like coal and sulphur can cause severe damage due to corrosion.
  4. Common cargoes like coal, sulphur, cotton, and fishmeal are liable to spontaneous heating. Coal also emits methane which is a flammable gas. When mixed with air it can form an explosive mixture.
  5. Dust created by certain cargoes may constitute an explosion hazard. Sulphur dust can readily ignite causing an explosion.
  6. Friction between cotton bales can cause spontaneous combustion and produce heat.
  7. Ammonium nitrate-based fertilisers support combustion. If heated, contaminated or closely confined, they can explode or decompose to release toxic fumes and gases.
  8. Metal sulphide concentrates. Some sulphide concentrates are prone to oxidation and may have a tendency to self-heat, leading to oxygen depletion and emission of toxic fumes. Some metal sulphide concentrates may present corrosion problems.
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What is a mast riser? What is the use of mast riser and Regulation as per ISGOTT.

In Crude oil tankers and vessels carrying homogeneous cargo, We can use just one line for venting purpose as all the cargo is homogeneous(same). From all the cargo tanks venting pipelines lead to the Mast riser. The mast riser is fitted with a valve (called mast riser valve). Use of mast riser – While loading the pressure inside the cargo tank is released through the mast riser by opening the mast riser valve and also the cargo tank pressure is monitored and if required the mast riser valve is throttled to maintain the cargo tank pressure at certain level. During discharging cargo to avoid negative pressure in the tank, the inert gas is continuously supplied to the cargo tanks.

The exhaust of mast riser must be at least 6m above the deck.

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Whether to Ventilate or not to ventilate? For Cargo and ship sweat

The following information is necessary before deciding whether to ventilate or not:

  • Temperature and dewpoint of the outside air.
  • Temperature and dewpoint of the air inside the hold.
  • Temperature of the cargo surface.
  • Temperature of the steel structure (Ships) inside the cargo compartment and
  • The moisture content of hygroscopic cargoes if applicable.

Whether to Ventilate or not to ventilate?

The following basic Dew Point rule provides relevant guidance which is:

  • If the dew point of the air within the hold is higher than the dew point of the OUTSIDE atmosphere, then ventilate.
  • If the dew point of the air within the hold is lower than that of the OUTSIDE atmosphere, then do not ventilate.

ANOTHER WAY OF EXPRESSING THIS IS –

  • If the Dew point of the outside air is lower or equal to that of the hold atmosphere……continue ventilation.
  • If the Dew point of the outside air is higher than the hold atmosphere dew point ………do not ventilate with outside air.

A further extension of the basic rule must be examined depending upon the two basic types of cargo.

HYGROSCOPIC CARGO -Warm region to Cold region:

As the ship proceeds from a warm region to a cold region it will experience a gradual drop in the temperature and a drop in the dew point. The atmosphere within the hold will receive large quantities of moisture from the cargo.  Hence in a situation such as this, ventilate vigorously during the early stages but eventually the outside Dewpoint will be too low.

NON-HYGROSCOPIC CARGO –Warm region to Cold region: 

Ship sweat is inevitable but cargo unaffected unless, condensation drips back onto the cargo.

HYGROSCOPIC Cargo:Cold region to warm region:

Not critical, therefore ventilation not essential. In some cases on opening hatches at the discharge port immediate condensation may form on surface but will dry off as cargo is discharged.

Non-HYGROSCOPIC Cargo:Cold region to warm region:

No Ventilation. Cargo sweat would occur on the surface of the cargo if relatively warm moisture laden air was admitted.

If due to any reason it is not possible to take readings within the hold then ‘Three Degree Rule’ can be used;

  • During loading regular cargo temperatures should be recorded. Whilst on passage if the atmosphere dry bulb temperature is at least 3ºC cooler than the average temperature of the cargo when loaded, then ventilate the hold, if the temperature of the atmosphere is less than 3ºC cooler than the average temperature of the cargo when loaded, the do not ventilate the hold.
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Reasons for Ventilation for cargo on board? Why is cargo and ship sweat caused? Cargo sweat and Ship sweat.

It is a very simple topic and as common as everyday event like WHY Water bottle from fridge gets water on the outer surface.

A large number of cargo claims are made for goods transported by ships which have been damaged in transit. Much of this damage is caused by either ‘ships sweat’ or ‘cargo sweat’ and could be effectively reduced by prudent ventilation of cargo spaces.

Cargo or goods carried at sea are exposed to the atmosphere which is high in moisture content. Due to the very nature of the trade, cargo damage due to moisture continues to be a cause for concern to all parties in the trade. Very heavy cargo claims due to damage to cargo caused by moisture continue to be made.

Between 1996 and the year 2000 claims accounted for in excess of 2 million US dollars in only one P&I club.

Cargo ventilation, as statistics indicate, appears to be the most neglected or least understood aspects of cargo care & cargo operations.  It is also one such activity that does not attract the attention it deserves and more often than not it is too late by the time the consequences are realised.

Why is sweat caused onboard?

Sweat is caused by the condensation of saturated air on a cooler surface. It is formed when water vapor in the air within the hold condenses out into water droplets once the air is cooled below its dew point. The water droplets may be deposited onto the ship’s structure or onto the cargo.

Some definitions are useful in understanding sweat.

Dew point:

Is defined as the temperature at which air cannot absorb any more water vapour; i.e. it is saturated. In simple language if the air parcel falls below its dew point temperature, then the moisture within the air parcel will condense.

Saturation:

Means that a parcel of air has absorbed its maximum amount of moisture for that temperature, however raising the temperature will allow for more moisture to be absorbed.

Relative Humidity:

Is the ratio between the actual moisture content and the maximum moisture content that the parcel of air can contain.

Hygroscopic cargo:

Is cargo, which can absorb or give off moisture. They are mainly of plant origin. Since they may retain or absorb water, excessive amounts of inherent moisture may lead to significant self-heating and moisture migration within the cargo. This will result in cargo getting caked or rotting.

Examples of Hygroscopic cargo: Rice, flour, grain, coffee, tea.

Non-hygroscopic cargo:

Is cargo, which does not absorb or give off moisture. Cargoes like steel are non-hygroscopic but are liable to damage if the atmosphere is moist.

Cargo Sweat:

This results when water droplets are deposited on parts of the cargo when the surrounding air comes in contact with a cool cargo. For this to happen, the temperature of the cargo must be lower than the dew point of the surrounding air.The condensation which forms directly on the cargo, when the temperature of the cargo is less than the dew point of the air in the hold.This is generally associated with incorrect ventilation. That is introducing warm moist air into the hold with cold cargo.It usually occurs when the voyage is from a cold region to a warmer place and the outside air has a dew point above the temperature of the cargo.Cold cargo cools the air in contact with it and condensation takes place.

Ships sweat:

Is the condensation which forms directly on the vessels structure when the temperature of the ship’s steel work is lower than the dew point of the air inside the hold. Condensation so formed on the structure will then trickle down to the cargo. This can occur when the ship moves to cooler climates (from a relatively warm area) and the ship’s sweat so formed can trickle onto the cargo or even accumulate at the bottom of the hold.

Related TOPICS

Whether to Ventilate or not to ventilate?

Hygroscopic and NON- Hygroscopic

List of cargoes which generate heat, gases and moisture:

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Determine compass error using the azimuth of a star.

Sample calculation (Azimuth-Stars):


Let’s LEARN WITH AN EXAMPLE –

On 05 May 2006 at 11h00m00s UTC, a vessel in position 04°30’N 010°00’W observed Canopus – bearing 145° by compass. Find the compass error. If variation was 4.0° East, calculate the deviation.


GHA Aries  (05d 11h): 028° 10.7°
Increment (00m 00s): 000° 00.0
(adding +)
GHA Aries: 028° 10.7
Longitude (W): – 010° 00.0′ (minus- since longitude is westerly)
LHA Aries: 018° 10.7


SHA Canopus: 263° 59.0
LHA Canopus: 282° 09.7′

Declination:
 S 052° 42.1
P= 360 – 282° 09.7° = 77° 50.3″ (IF LHA>180, P=360-LHA)
A = Tan Latitude/ Tan P
A = Tan 04° 30′ / Tan 77° 50.3
A = 0.016960803 S (A is named opposite to latitude, except when hour angle is between 090° and 270°)

B = Tan Declination / Sin P
B= Tan 052° 42.1′ / Sin 77° 50.3
B = 1.342905601 S (B is always named same as declination)


C = A+B = 1.359866404 S (C correction, A+/- B: If A and B have same name- add, If different name subtract)


Tan Azimuth = 1/(C X Cos Latitude)
 Tan Azimuth = 0.737640253
Azimuth = S 36.4° E (Azimuth takes the combined name of C correction and Hour Angle- If LHA is between 0°and 180°, it is named west”, if LHA is between 180° and 360°, it is named “east”).


True Azimuth= 143.6°
Compass Azimuth= 145.0°
Compass Error = 1.4° West
Variation = 4.0° East
Deviation = 5.4° West

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How to find compass error (using Azimuth of the sun).

Required Information –

  • GMT
  • Longitude and Latitude
  • Gyro heading and Compass heading
  • Gyro bearing of SUN (As most probably the azimuth circle will give you Gyro bearing and not Magnetic bearing).

Calculations –

Calculate for Nautical Almanac the GHA of the SUN

GHA (Day and Hour ) : __________

INCREMENT (Minutes) : ___________

Add both you will get GHA of SUN.

Then GHA (SUN) + Longitude (+ if E / – if west) = LHA(SUN)

Leave this information aside we will need it later, Next, we will find DECLINATION of the Sun using Almanac (Days page).

DECLINATION (Day and Hour)

+/- D-Correction ()

With this you will get your DECLINATION.

Now we need to find LHA

If LHA is more than 180 (P=360-LHA ) & If LHA is less than 180 (P = LHA).

A = TAN (LATITUDE) / TAN (P)

When hour angle is between 270 to 090, A is named opposite to latitude.

when hour angle is between 090 and 270 Degree, A is named same as latitude.

B= TAN (DECLINATION) / SIN (P)

B is always named same as declination.

C = A +/- B

If A and B both have same sign then we add them, If they have diffrent sign we substract them and put the sign of the bigger side.

Tan Azimuth = 1/[(C * Cos (Lat)]

Azimuth takes combined name of C and Hour angle – If LHA is between 0 and 180, It is named “West”, If LHA is between 180 and 360, It is named as EAST.

NOW Compare TRUE AZIMUTH with the GYRO AZIMUTH of SUN, the diffrence is your compass error (GYRO).

HOW TO FIND COMPASS ERROR (MAGNETIC). 

Initially check your VESSEL heading in gyro and magnetic for example if gyro heading is 050 and magnetic heading is 054 then you know the difference is 4 , Now when you observe the bearing of the sun using azimuth circle you get Gyro azimuth lets say it is 080 then what will be your compass bearing? It will be 084, Similary to calculate compass error (magnetic) we use Observed Azimuth magnetic and the True Azimuth.