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Showing posts from November, 2018

If your Sewage Treatment Plant blower stop working then your Sewage Treatment Plant can work without any problem?

This question is generally asked to test your basic knowledge about the operation of machinery as we all know that if onboard STP is of anaerobic type then the microorganism break down biodegradable material in the absence of oxygen, but if it is of aerobic type then definitely STP will not work because Aerobic digestion is a bacterial process occurring in the presence of oxygen. If, however, there is insufficient oxygen for these bacteria then alternative bacteria dominate. These Anaerobic Bacteria produce Hydrogen Sulphide, Methane and Ammonia. These gasses are either highly toxic or flammable or both. In particular, Hydrogen Sulphide is toxic to humans in concentrations down to 10ppm and its flammable vapours are heavier than air so may build up in lethal pockets in enclosed spaces. So, if the blower stops working the aerobic bacteria may die and it will take a longer time to regenerate.

How will you clean the Sewage Treatment Plant on-board?

During the time of orals, everyone can able to tell the method but examiner wants to listen to what safety precautions you will take, that was important to mention before starting with the cleaning process. One of the biggest problem associated with the sewage treatment plant is gas hazards. Gas hazard in the sewage treatment plant are those due to inflammable and poisonous gases may be derived from three general sources. Low volatile liquids which enter as the part of sewage, or the product of fermentation or digestion of sewage. The inflammable or poisonous gases usually found in treatment plants are methane, carbon dioxide and possibly carbon monoxide and hydrogen sulphide if inhale in the cleaning process may cause death.

Marine Sewage Treatment Plant

The basic principle of working of a biological treatment  plant is decomposition of the raw sewage. This process is done by aerating the sewage chamber with fresh air. The aerobic bacteria survive on this fresh air and decompose the raw sewage which is dispose off in the sea. Air is a very important criteria in the functioning  of the biological sewage plant because if air is not present, it will lead to growth of anaerobic  bacteria which produces toxic gases that are hazardous to health. Also after decomposition  of the sewage with anaerobic bacteria, a dark black liquid causes discoloration of water which is not accepted  for discharging. Thus in a biological sewage treatment plant the main aim is to maintain the flow of fresh air. Division of processes: The biological sewage  plant is divides into three chambers Aeration Chamber Settling tank Chlorination and Collection tank Aeration Chamber: This chamber is fed with raw sewage which has been grinded to form smal

What is the use of by-pass valve in SCBA?

In any case, if the face shield of SCBA is leaking in the presence of poisonous gas. It might penetrate through the mask and made the person unconscious when we open the by-pass valve it will provide oxygen continuously and will maintain a positive pressure inside the face mask to prevent the entry of poisonous gas.

Why an extra Life raft provided in forward of the ship?

According to SOLAS chapter 3, section 3 of regulation 31 in cargo ships when the horizontal distance from the extreme end of the stem or stern of the ship to the nearest end of the closest survival craft is more than 100m shall carry, in addition to the normal liferaft requirements a liferaft stowed as far as forward or aft as is reasonable and practicable. Such liferaft or liferafts may be securely fastened so as to permit manual release.

MEO Class 4

Safety: Solas chapter 12 full Annex 6 full, mainly Voc part Dynamic stability, Gz curve Req for emg towing oil tanker shell exp plan Stealer plate FSS code full Swash bulkhead location, purpose Certificate Carried related to solas chapter 9 Motor: AE lo contamination all possible causes Purifier pairing disc, Lubrication, water transducer Water tube boiler entire construction, with nomenclature Fwg less vacuum reasons & effects, high salinity reasons ME unit overhaul, hydraulic jack All about Threads Turbocharger, purpose of diffuser, drawing Self and central priming arrangement of pumps Vacuum condenser safeties, why VC Copt, how water level maintained in VC types of gate valve if gate valve struck inside, what will happen ,what will be ur action Air starting valve TIMING diagram for single unit counter weights in crankshaft (in ME & AE - how it is fitted) types of fuel injection  bilge valve, diff between sdnr nd slv shaft earthing , what to

MEO Class 2

Safety: IEEC certificate under which annexure and chapter, validity Required eedi, attained eedi with formula MLC Certificate and port state inspection why came in force in2013, not 2006 .no of article in it. Dynamic test of lifeboat. Maintenance of centrifugal brake as 2nd engineer, no of brake. NOx technical file content.  Maintenance of portable fire extinguishers as per DG shipping. In the container ship, there are some box tell me the name of all. Sopep , what information , why provided , who approves??? why mild steel used for ship building , carbon %, difference between strength & hardness Instantaneous rate of discharge Precaution during inclining experiment. Annexe 3 Reception facilities Propeller pitch ratio. Centre of floatation. Safeties for bulk carrier About high density cargo loading What are all the rules regarding triangle marking on bulkcarrier loading high density cargo...wheater applicable to all types of bulk carrier loading high density

MEO Class 4

Safety: Marpol annex What is dead weight ? What is displacement? Freeboard and why is it given? Reason for different freeboard in tanker and bulk carrier. MARPOL 73/78 all annexes in brief. Annex 6 in detail. With certification. Difference between IAPP and EEDI. Bilge keel and how it is welded, why? Types of plate Types of rudder Sprouling hose Co2 room regulations Fixed fire fighting system Co2 cylinder calculation Cylinder classification Bilge discharge criteria Sewage discharge,criteria and about bod Anchor chain bitter end purpose Ism objectives Bulwark Isps level 3 Components of annex 6 Hypermist system and checks carried out All Statutory certificates carried by ship. Difference between type 1 2 3 tanker.  Safeties in Life boat Emergency generator regulations. All of them. Explain oil discharge criteria Solas chapter 12 explain Mlc all tittles Hypermist draw and explain Statical stability Draw and explain ship righting lever and trigonometry cal

MEO Class 4

Safety: IG safeties gave explanation of each and every alarm with value and what things will stop or open  Pump room safeties gave explanation how you enter  Collision bulkhead In collision bulkhead gave and with one opening allowed and also two opening may be allowed and related valve position how operate and like that ... Displacement, deadweight All marpol annexes . Annex  6. Certificates in it. Solas chapter 9. Life boat safeties Extinguisher present near boiler, capacity Marginal line Free board Permeability Air draft Lifeboat safety Davit safety Pumping out regulation in annex 1 Motor & MEP: How easing gear work? Safety valve lift value not formula? Why c- for compact engine...MAN Boiler mounting Air compressor safety How 4 stoke cylinder lubrication take place. Fire pump priming arrangement One unit exhaust temp rising Labyrinth seal how it works t/c Reversing man b&w Tap and die How to measure height of purifier shaft How to check t


The main purpose of the calculation is to find the freeboard draught (maximum allowable draught). The rule reference is the International Convention of Load Lines, 1966. The first step in freeboard calculation is deciding the type of freeboard. There are two kinds, Type 'A' and Type 'B'. Usually Type 'A' ships are the ones designed to carry liquid cargoes in bulk, where the cargo, tanks have small assess openings. Because of small access to the cargo and lack of floodable volume after damage in case of a loaded ship, such ships can have a low freeboard compared to Type 'B' ships. Such a ship necessarily has the following features: High integrity of the exposed deck, and High degree of safety against flooding, resulting from the low permeability of loaded cargo spaces and the degree of subdivision usually provided.   Type 'B' ships are all the other ships other than Type 'A', and these have larger freeboard (or lower maximu

Load Line & Why it is Important

Merchant ships have a marking on their hull know as the Plimsoll line or the Plimsoll mark, which indicates the limit until which ships can be loaded with enough cargo, internationally, the Plimsoll line on a ship is officially referred to as the international load line. Every type of ship has a different level of floating and the Plimsoll line on a ship generally varies from one vessel to another.  All vessels of 24 meters and more are required to have this Load line marking at the centre position of the length of summer load water line. There are two types of Load line markings:- Standard Load Line marking – This is applicable to all types of vessels. Timber Load Line Markings – This is applicable to vessels carrying timber cargo. These marks shall be punched on the surface of the hull making it visible even if the ship side paint fades out. The marks shall again be painted with white or yellow colour on a dark background/black on a light background.  The comp

Why Rudder Angle Limited Upto 35 degree only?

The answer is Rudder Stall . Flow around the rudder is smooth at small angles of attack. Lift increases-proportionally to the angle of attack (i.e rudder angle). Flow separates across the rudder at larger angles (>20'~30') causes the lift force to drop drastically This drop in lift is accompanied by a drastic increase in drag This is why practical limits(hard stops) are set on rudders ~35'. Angle of attack: It is the angle made by the direction of the incoming fluid and the plane of the rudder.  Critical angle of attack: Critical angle of attack is the angle of attack at which the fluid flow across the rudder separates. i.e. at critical angle, the fluid flow is such that the formation of eddies behind the face of rudder increase to such an extent that instead of guiding the fluid flow, the rudder tends to stop the fluid flow.  Depending upon the drag, viscosity, blade shape and flow characteristic of the fluid, the critical angle varies for

Classification of Chemical Tankers

As per IBC code, ships carrying chemical in bulk are classified under three category: A type 1 ship is a chemical tanker intended to transport chapter 17 products with very severe environmental and safety hazards which require maximum preventive measures to preclude an escape of such cargo. A type 2 ship is a chemical tanker intended to transport chapter 17 products with appreciably severe environmental and safety hazards which require significant preventive measures to preclude an escape of such cargo. A type 3 ship is a chemical tanker intended to transport chapter 17 products with sufficiently severe environmental and safety hazards which require a moderate degree of containment to increase survival capability in a damaged condition. Thus a type 1 ship is a chemical tanker intended for the transportation or products considered to present the greatest overall hazard and type 2 and type 3 for products of progressively lesser hazards. Accordingly, a type 1 ship should