Different Types of alarms on Ships

An emergency does not come with an alarm but an alarm can definitely help us to tackle an emergency or to avoid an emergency situation efficiently and in the right way. Alarm systems are installed all over the ship’s systems and machinery to notify the crew on board about the dangerous situation that can arise on the ship.

Alarm on board ships are audible as well as visual to ensure that a person can at least listen to the audible alarm when working in a area where seeing a visual alarm is not possible and vice versa.

It is a normal practice in the international maritime industry to have alarm signal for a particular warning similar in all the ships, no matter in which seas they are sailing or to which company they belongs to. This commonness clearly helps the seafarer to know and understand the type of warning or emergency well and help to tackle the situation faster.

The main alarms that are installed in the ship to give audio-visual warnings are as follows:

1) General Alarm: The general alarm on the ship is recognized by 7 short ringing of bell followed by a long ring or 7 short blasts on the ship’s horn followed by one long blast. The general alarm is sounded to make aware the crew on board that an emergency has occurred.

Credits: Todd Lappin/flikr.com

2) Fire Alarm: A fire alarm is sounded as continuous ringing of ship’s electrical bell or continuous sounding of ship’s horn.

3) Man Overboard Alarm: When a man falls overboard, the ship internal alarm bell sounds 3 long rings and ship whistle will blow 3 long blasts to notify the crew on board and the other ships in nearby vicinity.

4) Navigational Alarm: In the navigation bridge, most of the navigational equipments and navigation lights are fitted with failure alarm. If any of these malfunctions, an alarm will be sounded in an alarm panel displaying which system is malfunctioning.

5) Machinery space Alarm: The machinery in the engine room has various safety devices and alarms fitted for safe operation. If any one of these malfunctions, a common engine room alarm is operated and the problem can be seen in the engine control room control panel which will display the alarm.

6) Machinery Space CO2 Alarm: The machinery space is fitted with CO2 fixed with fire extinguishing system whose audible and visual alarm is entirely different from machinery space alarm and other alarm for easy reorganization.

7) Cargo Space CO2 Alarm: The cargo spaces of the ship are also fitted with fixed fire fighting system which has a different alarm when operated.

8) Abandon Ship Alarm: When the emergency situation on board ship goes out of hands and ship is no longer safe for crew on board ship. The master of the ship can give a verbal Abandon ship order, but this alarm is never given in ship’s bell or whistle. The general alarm is sounded and every body comes to the emergency muster station where the master or his substitute (chief Officer) gives a verbal order to abandon ship.

9) Ship Security Alarm System: Most of the ocean going vessels are fitted with security alert alarm system, which is a silent alarm system sounded in a pirate attack emergency. This signal is connected with different coastal authorities all over the world via a global satellite system to inform about the piracy.

Different Alarm signals of the vessel are clearly described in the muster listalong with the action to be carried out so that all the crew member can perform there duties within no time in actual emergency.

#Ship Squad Formula

Ship Squqt formula

Find the approximate calculated squat of your vessel is proceeding to a channel #not enclosed with a width of 90 meters deep and dredge surrounding depths of 20 meters. Your vessel's draft is 11 meters and beam of 27 meters, speed 7 knots and block coefficient is 0.8 

Given:

Speed = 7 knots

Block Coefficient = 0.8

What is asked?

Ship's squat

Solution:

This is the ship's squat formula on open waters and the unit of the answer will be meter.

  Squat = Block Coefficient x Speed² /100

                                 = (0.8 x 7²)/100

                                 = (0.8 x 49)/100

                                 = 39.2 / 100

                       #Squat = 0.392 m      

Again, the example above is that we get  the value of the ship's squat in open waters. You might asked then, if there's a formula for squat on open waters, what will be the formula for squat on #enclosed water?

To get the value of squat on enclosed water is to multiply block coefficient by the square of speed, and then times 2, then divide the product by 100.

Here is the problem for squat on closed water. 

A container vessel of 12,000 tons displacement is approaching her berth at speed of 4 knots. Its block coefficient is 0.78. Calculate the value of squat.

Answer: 0.25 meters

  Squat = (Block Coefficient x Speed²)×2 /100

                                 = (0.78 x 4²) × 2 /100

                                 = (0.78 x 16) × 2 /100

                                 = 24.96 / 100

                       #Squat = 0.25 m  

#Draft_Survey_Procedures_and_Calculation ...

#Draft_Survey_Procedures_and_Calculation ...           

The Draft Survey procedures and calculation ascertained as the following series :

01. Reading the draftmark of the ship, which consist of six (6) points of draftmarks, i.e.; Fore, Midship, and After at both sides of the ship,

02. Sampling and testing the sea water or dock water density at the place where the vessel floats,

03. Determining of deductible weights by measuring and sounding of ballast tanks, fuel oil, fresh water that existing onboard at the time of survey,

04. Using Hydrostatic Table provided onboard to calculation.

#Reading_the_Draftmark_of_the_ship 👇

Commonly, all ship are designed with draftmark for working with Draft Survey to determined their actual weight. 

The draftmark could be find at six (6) points on the below places:

●Forward Port Side (FP),

●Forward Starboard Side (FS),

●Midship Port Side (MP),

●Midship Starboard Side (MS),

●Aftward Port Side (AP),

●Aftward Starboard Side (AS),

Use the small boat to go around the ship and get as near as possible to the draft mark for best viewing. The surveyor should be read all above marks clearly, because reading the draftmark is the first and most essential process. I am not saying that other processses is not essensial, but this process is hard to do and involves many rules of conduct to gain the correctness and accuracy of Draft Survey itself (I will post it later). The draftmark read is recorded on the surveyor notebook, do not try to remember it or write down in your palm hand. Its useless and un-professional.

#Sampling_and_testing_the_sea_water_or_dock_water_density 👇

After reading the draftmark, directly engage with the sampling of sea water or river water around the ship’s dock.  Why? 

Because the ship draft will not be the same at different water densities (at the lower density means the ship more sink and at the higher density means the ship more float).  

Where as the water density is subject to changes which follow with water tide that carrying different water salinity and temperature on to the ship dock. 

The sea water density is indeed at density 1.025 and the fresh water at density 1.000. 

To determine the density of water, we need the instrument named Hydrometer or Density Meter. Inserted the Hygrometer on to the water sample on the Sampling Can or Tube, then we could check the scale pointed on the surface of the sampling water. Records the water dock density as survey data.

#Determining_of_deductible_weights_by_measuring_and_sounding 👇

Deductible Weight could measure by sounding  the tanks which used the Sounding Tape or gauging the tank level by visual inspection. 

Any deductible weight such as Ballast Water, Fresh Water, Fuel and Diesel Oil, and Bilges is notify to check. 

Records all in the survey book includes with the density for Ballast and Bilges, and for Oil complete it with density and temperature . The Fresh Water was at density 1.000.

#Using_Hydrostatic_Table_provided_onboard_to_begin_calculation 👇

I think all necessary data was completed, so we could do calculation. 

The calculation is uses Displacement Table or usually called Hydrostatic Table. This table is included all data that we need to complete the calculation.

●Raw Draft Calculation; 

Fore Mean or Fm = (FP+FS)/2, 

Mid Mean or Mm = (MP+MS)/2, and Fore Mean or Am = (AP+AS)/2. 

while Apparent Trim  or AT = Am – Fm. 

the Apparent Trim is the Trim that visually find.

●Draftmark posision and correction to perpendicular. 

As the ship draftmark is not placed at the perpendicular, the Fore and After draft should be corrected with distance from the draftmark to perpendicular. 

The correction rules is: if the Trim by Stern, the Fore correction should be minus and After correction plus, and if the Trim by Head (stem), the Fore correction should be plus and After correction minus. 

The Midship correction is parallel with the fore correction with the same pattern. 

Some Hydrostatic table provided with these correction result. 

But if not the reference pattern is  for 

Fore Correction or Fc = (Fd x AT) : LBM and After Correction or Ac = (Ad x AT) / LBM. Where Fd = Fore distance to perpendicular, 

Ad = After distance to perpendicular, and LBM = Length Between Mark or Length between Fore and After draftmarks  or 

LBM = LBP – (Fd + Ad).

●True Draft Calculation / Draft Corrected; 

Fore draft corrected or Fcd = Fm + Fc, 

Mid draft corrected or Mcd = Mm + Mc, 

and After draft corrected or Acd = Am + Ac.

●True Trim or TT : Actual  Ship Trim after draft corrected or  TT = Acd – Fcd.

●Fore and After Mean Draft or FAm = (Fcd + Acd)/2, Mean of Mean Draft or MM = (FAm + Mcd)/2, and Mean of Mean of Mean Draft  or MMM or Quarter Mean = (MM + Mcd)/2.

●The above calculation is similar with : 

MMM = {(Fcd x 1) + (Acd x 1) + (Mcd x 6)}/8.

●Coresponding to the MMM or Quarter Mean result, the surveyor could check the value of needed parameters on Hysdrostatic table like; Displacement, TPC, LCF, and MTC. Records them accurately.

●Get the Displacement or Disp.

●First Trim Correction or 

FTc = (TT x LCF x TPC x 100) / LBP. 

Could be plus or minus depend on LCF.

●Second Trim Correction 

STc = (TT x TT x MTC x 50) / LBP. 

The result always plus (+).

●Displacement corrected by Trim or 

DispT = D – (FTc + STc).

●Density Correction or 

Denc = DispT x {(Aden – 1.025) / 1.025}. 

where the Aden is Actual Density that surveyor has taken sampling and testing previously. 

The density correction commonly in minus (-), due to the Actual Density is usually lower than 1.025 (fresh sea water). 

In case of at some port where the water salinity is high, the density correction could be plus (+).

●And we have got the Displacement corrected by Density or 

DispDenc = DispT + Denc. (after corrected by density we will get the actual ship weight as per shown by Draft Survey)

●Deductible Calculation. The same as draft, the deductible also need to corresponding to the table that named Tank Table / Tank Capacity Table. 

Refer to the sounding records that done before, the surveyor could be calculate the total deductbile existing onboard. 

Total Deductible or Deduct =  Ballast Water + Fresh Water + Bilges + Fuel Oil + Diesel Oil,  this total should be minus to the Displacement corected by Density.

●The Net Displacement or 

NDisp = DispDenc – Deduct.

●The Net Displacement is the actual ship weight after minus with deductible weight. For Unloading, to estimate the quantity of cargo onboard, the Net displacement should be minus with Light Ship and Constant.👌

#Ship Captain

The_Captain  

The captain studies chemistry, physics, mathematics, engineering, medicine, and ample medicine if anyone is sick, climate science, meteorology, management science, and law.

   To be familiar with everything, they are all sciences that are not in his major specialization, and a guest of this nautical marine sciences is his primary specialization and many branches.

  He must pass all of this by 70%.

  The captain studies certificates, marine courses, and other courses in various sciences that may exceed 30 certificates, in contrast to the basic marine subjects that the article cannot mention

  As he is the first responsible for the ship that raises the flag of the state in the seas, oceans, channels and international shipping lanes

  And on it some other responsibilities that the article cannot mention ....

  The certificates of the captain, engineers, marine officers and sailors are renewed every 5 years, and all his inevitable certificates, marine passports and educational courses are revoked, he returns to the zero point and begins his studies again. Compulsory academic system in all parts of the world belong to the International Maritime Organization of the United Nations as the certificates are international certificates.

  It is the only field in the world from which graduates remain associated with studying at the college or academy for the last practical and scientific life of which is (a mandatory global system is mandatory)

  Plus, as the ship's maneuvering in the water is more difficult to maneuver and more difficult than maneuvering the aircraft and more difficult than any maneuver for any machine to march or otherwise (according to an article from the UKHO office in 2017)

  The work of the sailor is classified as one of the most dangerous, most difficult and dangerous jobs, and the error in it has great harm on the human and economic side, according to (the BBC) documentary film. The sailors November 2017)