Ship Construction....

Ship Construction...

              Several basic ship types are considered. The particular features of appearance, construction, layout, size, etc., will be examined for the various ship types.

• General cargo ships: 

1. The general cargo consists of as large a clear open cargo-carrying space as possible, together with the facilities required for loading and unloading the cargo.
2. Access to the cargo storage areas or holds is provided by openings in the deck called hatches. Hatches are made as large as strength considerations will allow to reduce horizontal movement of cargo within the ship.
3. Hatch covers of wood or steel, as in most modern ships, are used to close the hatch openings when the ship is at sea. The hatch covers are made watertight and lie upon coamings around the hatch which are set some distance from the upper or weather deck to reduce the risk of flooding in heavy seas.
4. One or more separate decks are fitted in the cargo holds and are known as tween decks. Greater flexibility in loading and unloading, together with cargo segregation and improved stability, are possible using the tween deck spaces.
5. Various combinations of derricks, winches and deck cranes are used for the Handling of cargo.
6. The accommodation and machinery spaces are usually located with one hold between them and the  aft peak bulkhead.

• Tankers:

1. The tanker is used to carry bulk liquid cargoes, the most common type being the oil tanker.
2. The oil tanker has the cargo-carrying section of the vessel split up into individual tanks by longitudinal and transverse bulkheads.
3. Double bottom or/and double sides or double hull is fitted in the cargo-carrying section of an oil tanker.
4. A pair of wing tanks are created by longitudinal bulkheads. These wing tanks helps reduces the free surface effect.
5. Large amounts of piping are to be seen on the deck running from the pump rooms to the discharge manifolds positioned at midships, port and starboard.

* LNG tankers carry methane and other paraffin products obtained as byproduct of petroleum drilling operations. The gas is carried at atmospheric pressure and temperatures as low as −164 °C in tanks of special materials, which can accept the low temperature. The tanks used may be prismatic, cylindrical or spherical in shape and self-supporting or of membrane construction.

* LPG tankers carry propane, butane, propylene, etc., which are extracted from natural gas. The gases are carried either fully pressurized, part pressurized part refrigerated or fully refrigerated. The fully pressurized tank operates at 1800 kPa and ambient temperature, the fully refrigerated tank at 25 kPa and −50 °C. Tank shapes are prismatic, spherical or cylindrical. Low temperature steels may be used on the hull where it acts as a secondary barrier.

• Bulk/ore carriers:

1. Bulk carriers are single-deck vessels, which transport single-commodity cargoes such as grain, sugar and ores in bulk.
2. The general-purpose bulk carrier, in which usually the central hold section only is used for cargo
3. The partitioned tanks which surround it are used for ballast purposes either on ballast voyages or; in the case of the saddle tanks, to raise the ship's center of gravity when a low density cargo is carried.
4. Some of the double-bottom tanks may be used for fuel oil and fresh water.
5. The saddle tanks also serve to shape the upper region of the cargo hold and trim the cargo. Large hatchways are a feature of bulk carriers, since they reduce cargo-handling time during loading and unloading.

• Ore carriers:

1. An ore carrier has two longitudinal bulkheads, which divide the cargo section into wing tanks port and starboard, and the center hold, which is used for ore.
2. On loaded voyages the ore is carried in the central hold, and the high double bottom serves to raise the center of gravity of this very dense cargo.
3. Two longitudinal bulkheads are employed to divide the ship into center and wing tanks which are used for the carriage of oil cargoes.
4. When ore is carried, only the center tank section is used for cargo.
5. A double bottom is fitted beneath the center tank but is used only for water ballast.
6. The structure is significantly stronger, since the bulkheads must be oil tight and the double bottom must withstand the high-density ore load.
7. Large hatches are a feature of all bulk carriers, to facilitate rapid simple cargo handling.
8. A large proportion of bulk carriers do not carry cargo-handling equipment, because they trade between special terminals which have particular equipment for loading and unloading bulk commodities.

• Container ships: 

1. A container is a re-usable box of 2435 mm by 2435 mm section, with lengths of 6055, 9125 and 12 190 mm.
2. Containers are in use for most general cargoes, and liquid-carrying versions also exist. In addition, refrigerated models are in use.
3. The cargo-carrying section of the ship is divided into several holds which have hatch openings the full width and length of the hold.
4. Cargo handling consists only of vertical movement of the cargo in the hold.
5. Containers can also be stacked on the hatch covers where a low-density cargo is carried.
6. The various cargo holds are separated by a deep web-framed structure to provide the ship with transverse strength
7. The ship section outboard of the containers on each side is a box-like arrangement of wing tanks, which provides longitudinal strength to the structure. These wing tanks may be utilized for water ballast.
8. A double bottom is also fitted which adds to the longitudinal strength and provides additional ballast space.

• Passenger ships:

1. The passenger traveling in such a ship pays for, and expects, a superior standard of accommodation and leisure facilities.
2. Large amounts of superstructure are therefore an essential feature of passenger ships.
3. Several tiers of decks are filled with large open lounges, ballrooms, swimming pools and promenade areas.
4. Stabilizers are fitted for reduce rolling and bow thrust devices are employed for improved maneuverability.

            

Precaution Before Joining Ship.....

Before You Board:

  1.  Don’t start work on a ship without having a written contract.

 2.  Never sign a blank contract, or a contract that binds you to any terms and conditions that are not specified or  that you are not familiar with.

 3.  Check if the contract you are signing refers to a Collective Bargaining Agreement (CBA). If so, make sure that you are fully aware of the terms of that CBA, and keep a copy of it along with your contract.

 4.  Make sure that the duration of the contract is clearly stated.

 5.  Don’t sign a contract that allows for alterations to be made to the contractual period at the sole discretion of the shipowner. Any change to the agreed duration of the contract should be by mutual consent.

 6.  Always ensure that the contract clearly states the basic wages payable and make sure that the basic working hours are clearly defined (for example 40, 44 or 48 per week). The International Labour Organisation states that basic working hours should be a maximum of 48 pr week (208 per month).

 7.  Make sure that the contract clearly stipulates how overtime will be paid and at what rate. There could be a flat hourly rate payable for all hours worked in excess of the basic. Or there may be a monthly fixed amount for a guaranteed number of overtime hours, in which case the rate for any hours worked beyond the guaranteed overtime should be clearly stated. The ILO states that all overtime hours should be paid at a minimum of 1.25 x the normal hourly rate.

 8.  Make sure that the contract clearly states how many days paid leave per month you will get. The ILO states that paid leave should not be less than 30 days per year (2.5 days per calendar month).

 9.  Make certain that the payments for basic wages, overtime and leave are clearly and separately itemised in the contract.

10.  Don’t sign a contract that allows the shipowner to withhold or retain any portion of your wages during the period of the contract. You should be entitled to full payment of wages earned at the end of each calendar month.

11.  Never sign a contract that contains any clause stating that you are responsible for paying any portion of your joining or repatriation expenses.

12.  Don’t sign a contract that contains any clause that restricts your right to join, contact, consult with or be represented by a trade union of your choice.

13.  Be aware that an individual employment contract will not always include details of additional benefits. Therefore you should try to obtain confirmation (preferably in the form of a written agreement or contractual entitlement) of what compensation will be payable in the event of:

            – Sickness or injury during the contractual period
            – Death (amount payable to the next of kin)
            – Loss of the vessel
            – Loss of personal effects resulting from the loss of the vessel
            – Premature termination of the contract.

14.  Ensure that you are provided with and retain a copy of the contract you have signed.

15.  Remember… whatever the terms and conditions, any contract/agreement that you enter into voluntarily would, in most jurisdictions, be considered legally binding.

Types Of Merchant Ships...

Merchant Ship Categories....

• Roll on/ Roll off ship:

                     Roll-on/roll-off (RORO or ro-ro) ships are vessels designed to carry wheeled cargo, such as automobiles, trucks, semi-trailer trucks, trailers and railroad cars that are driven on and off the ship on their own wheels. This is in contrast to lo-lo (lift-on/lift-off) vessels which use a crane to load and unload cargo.

                  RORO vessels have built-in ramps which allow the cargo to be efficiently "rolled on" and "rolled off" the vessel when in port. While smaller ferries that operate across rivers and other short distances often have built-in ramps, the term RORO is generally reserved for larger ocean-going vessels. The ramps and doors may be stern-only, or bow and stern for quick loading.

                                       Roll on/ Roll off ship

                 There are various types of ro-ro vessels, such as ferries, cruise ferries, cargo ships, and barges. The ro-ro vessels that are exclusively used for transporting cars and trucks across oceans are known as Pure Car Carriers (PCC) and Pure Truck & Car Carriers (PCTC) respectively. Unlike other cargos that are measured in metric tonnes, the ro-ro cargo is measured in a unit called lanes in meters (LIMs). LIM is calculated by multiplying cargo length in meters by the number of decks and by its width in lanes. The lane width will differ from vessel to vessel and there are a number of industry standards.
 Advantages of a ro-ro ship:

1. For the shipper, the advantage is speed. Since cars and lorries can drive straight on to the ship at one port and then drive off at the other port within a few minutes of the ship docking, it saves a lot of time of the shipper.
2. It can also integrate well with other transport development, such as containers. The use of Customs-sealed units has enabled frontiers to be crossed with the minimum of delay. Therefore, it increases the speed and efficiency for the shipper.
3. The ship has also proved extremely popular with holiday makers and private car owners. It has significantly contributed to the growth of tourism. A person can take his car from one country to another by sea with the help of a ro-ro vessel.

• TUGBOAT (Tugs):

                         A tugboat (tug) is a boat that maneuvers vessels by pushing or towing them. Tugs move vessels that either should not move themselves, such as ships in a crowded harbor or a narrow canal, or those that cannot move by themselves, such as barges, disabled ships, log rafts, or oil platforms. Tugboats are powerful for their size and strongly built, and some are ocean-going. Some tugboats serve as icebreakers or salvage boats. Early tugboats had steam engines, but today most have diesel engines. Many tugboats have firefighting monitors, allowing them to assist in firefighting, especially in harbors.

• Another types:

1. Refrigerated cargo ship: Use to carry fruit, meat and other food product across the sea in fresh & clean manner.

  2.  Livestock carriers: Use to transport live animals from one country to another.

Types of Merchant ship...

Merchant ships names are prefixed by which kind of vessel they are:

• MV = Motor Vessel
• SS = Steam Ship
• MT = Motor Tanker or Motor Tug Boat
• MSV = Motor Stand-by Vessel
• MY = Motor Yacht
• RMS = Royal Mail Ship
• RRS = Royal Research Ship
• SV = Sailing Vessel (although these can be sub coded as type of sailing vessel)
• LPG = Gas carrier transporting liquefied petroleum gas
• LNG = Gas carrier transporting liquefied natural gas
• CS = Cable Ship or Cable layer.

Merchant Ship Categories....

• Dry cargo ships:

               Until vessels started to be built to carry specific cargoes, all vessels were simply general or dry cargo vessels, i.e. built to carry any and all cargoes either in drums and bales or on pallets. Such cargoes were put in general holds with no specialization. The role of the general/dry cargo vessel began to wane with the arrival of bulk-carriers and tankers, but the decline of these general vessels has accelerated since the arrival of containerization (in the 1960's). Not only are container ships able to carry greater volumes of cargo in standard shaped cargo containers, the time spent loading and discharging has been dramatically reduced. Whereas a dry cargo vessel may take 3 - 4 days to load or discharge, a container ship can achieve the same in a matter of hours. Although general/ dry cargo vessels remain as the largest (in pure numbers) of cargo carrying vessels, they are often smaller (rarely above 50,000 Gross tons) than the specialized vessels that are slowly replacing them.
                  

• Bulk Carriers:

Bulkcarriers ("bulkers"), are the great work horses of the shipping world, carrying raw dry cargoes in huge cavernous holds, such as coal, iron ore, grain, sulphur, scrap metal. Until recently, there had been a huge demand for these vessels, driven by the extraordinary expansion of the Chinese economy. Imports of iron ore into China boosted the earnings of bulk carrier owners as freight rates went through the roof into uncharted territory. For a 'Capesize' bulkcarrier, daily hire rates of over $280,000 per day were recorded. Then came the downturn in late 2008 and freight rates have slumped, with bulkcarriers struggling to be fixed above $20,000 ! - quite a dramatic change in only a few months. Unfortunately, huge numbers of these vessels were ordered from shipyards during the 'boom' times. Taking about 2 years to build, many of these new ships will be delivered only to be sent probably straight to lay-up, as no work can be found for them.                 There are two types of bulkcarriers , one is that rare beast called a "Geared" bulkcarrier, because it carries it's own cargo cranes and another one is a more regular design of "Gearless" bulkcarrier.                          Geared bulkcarriers                                                             Gearless bulkcarriers                     Bulkers range from about 25,000 DWT ("handysize") through the medium size ("Panamax")vessels of about 75,000 DWT, to the giant ("capsize") vessels of up to 200,000 DWT (Some go bigger than that even !). Demand for the large "Capesize" bulkcarriers has never been higher, and there are a few "subdivisions" within this "Capesize" type, such as "Kamsarmax" (being the largest vessels able to enter the port of Kamsar, Equatorial Guinea, at about 175,000 DWT), "Newastlemax" (being the largest to be able to enter the port of Newcastle, Australia at about 185,000 DWT) and "Setouchmax" (being the largest able to navigate the Setouch Sea, Japan at about 203,000 DWT). With such high demand outstipping supply, some Very Large Crude Carriers are being converted to Very Large Ore Carriers (VLOC) and this is now a new size type for bulkcarriers over 200,000 DWT. Due to the heavy use that these vessels are put to, their life-expectancy is less than it would be for say, a container ship.

• Tankers:

A Tanker is a ship designed to transport liquid in bulk. Major types of tankers include the Oil tanker, the Chemical Tanker, and Gas carrier.                                                      Oil Tanker Chemical Tanker LNG Carrier              An oil tanker, also known as a petroleum tanker, is a merchant shipdesigned for the bulk transport of oil. There are two basic types of oil tankers: the crude tanker and the product tanker. Crude tankers move large quantities of unrefined crude oil from its point of extraction to refineries. Product tankers, generally much smaller, are designed to move petrochemicals from refineries to points near consuming markets.              Tankers are designed to carry liquid cargoes (not just oil) although the carriage of crude oil has brought the tanker unwelcome attention and largely unjustified criticism. Oil tankers come in two basic flavours, the crude carrier, which carries crude oil, and the clean products tanker, which carries the refined products, such as petrol, gasolene, aviation fuel, kerosene and paraffin. Tankers range in all sizes, from the small bunkering tanker (used for refuelling larger vessels) of 1000 DWT tons to the real giants: the VLCC (Very Large Crude Carrier) of between 2-300,000 DWT and the ULCC (Ultra Large Crude Carrier) of over 300,000 DWT. Types of tankers: Handysize Tanker: 20,000-30,000 DWT. Handymax Tanker : Approx. 45,000 DWT. Panamax Tanker: Approx. 79,000 DWT. Aframax Tanker: Between 79,000-1,20,000 DWT. Suezmax Tanker: Between 1,20,000-1,80,000 DWT. V.L.C.C. Tanker: Between 2,00,000-3,00,000 DWT. U.L.C.C. Tanker: Over 3,00,000 DWT.             It should be remembered that over 60% of the world's oil is transported by these tankers, and over 99% of that arrives safely without causing pollution. Indeed most oil pollution seen on beaches comes from the engine rooms of vessels (of all types) and not from the cargo tanks of tankers.

Crew Members on Ships....

2) ENGINE SIDE CREW MEMBERS:

• Chief Engineer
• Second Engineer/first assistant engineer
• Third Engineer/ Second assistant engineer
• Fourth Engineer/ Third assistant Engineer
• Engine Cadet
• Oiler
• Wiper
• Fitter
• Motorman
• Machinist

                                                                                                                           

Chief Engineer:
            

             A chief engineer (commonly referred to as "The Chief" or just "Chief") is responsible for all operations and maintenance that has to do with any and all engineering equipment throughout the entire ship.

            Under many jurisdictions the Chief Engineer is of equal rank to the Captain, with responsibility being split between the two posts; the Chief Engineer taking responsibility for engine room and maintenance and the Captain taking responsibility for navigation and deck operations.

            The chief engineer also determines the fuel, lube oil, and other consumables required for a voyage. The chief engineer also compiles an inventory for spare parts, oversees fuel, lube, and slop oil transfers, all major maintenance, prepares the engine room for inspection by local marine/safety authorities and and is in charge of the engine room during emergency situations.

            Sailing as chief engineer is an immense undertaking of great responsibility.

Second Engineer/first assistant engineer:

                  

            A first assistant engineer(also called the second engineer in some countries) is a licensed member of the engineering department on a merchant vessel. This title is used for the person on a ship responsible for supervising the daily maintenance and operation of the engine department. They report directly to the chief engineer.

            On a merchant vessel, depending on term usage, "The First" or "The Second" is the marine engineer second in command of the engine department after the ship's chief engineer. Due to the supervisory role this engineer plays, in addition to being responsible for the refrigeration systems, main engines (steam/gas turbine, diesel), and any other equipment not assigned to the Second assistant engineer/third engineer or the Third assistant engineer/fourth engineer(s), he is typically the busiest engineer aboard the ship.

            The first assistant/second engineer is usually in charge of preparing the engine room for arrival, departure, or standby and oversees major overhauls on critical equipment.

Third Engineer/ Second assistant engineer:

               

            A Second Assistant Engineer or Third Engineer is a licensed member of the engineering department on a merchant vessel.

            The Second Assistant is usually in charge of boilers, fuel, auxiliary engines, condensate and feed systems, and is the third most senior marine engineer on board. Depending on usage, "The Second" or "The Third" is also typically in charge of fueling (a.k.a. bunkering), granted the officer holds a valid Person In Charge (PIC) endorsement for fuel transfer operations.

             He exact duties of this position will often depend upon the type of ship and arrangement of the engine department. On ships with steam propulsion plants The Second/Third is in charge of the boilers, combustion control, soot blowers, condensate and feed equipment, feed pumps, fuel, and condensers. On diesel and gas turbine propulsion plants The Second is in charge of auxiliary boilers, auxiliary engines, incinerator, air compressors, fuel, and fuel oil purifiers.

Fourth Engineer/ Third assistant Engineer:

               

             The Third Assistant Engineer, also known as the Fourth Engineer, is a licensed member of the engineering department on a merchant vessel.

            Generally the most junior marine engineer of the ship, this person is usually responsible for electrical, sewage treatment (resulting in the pejorative pun "turd engineer"), lube oil, bilge, and oily water separation systems. Depending on usage, they are called "The Third" or "The Fourth" and usually stands a watch and sometimes assists the third mate in maintaining proper operation of the life boats.

            With experience and additional training, third officers may qualify for higher rank.

Engine Cadet:

               The engine cadet closely follows the instructions of the First Engineer and attends the engine control room usually as part of the First Engineer's watch. The Engine Cadet assists in the maintenance and repair of engine room equipment, as well as other mechanical equipment throughout the ship. As part of the training process duties that are customary to the engine department will be assigned to the Engine Cadet by the Chief Engineer. Although on training the professional performance of the Engine Cadet will be evaluated for continued long-term career with the cruise line. Upon attainment of a National License and completion of at least one assignment aboard a cruise ship the most qualified candidates with the best performance evaluations could be promoted to Third Engineer position depending on current openings in the company's fleet.

Oiler:

             Oiler is an engine department rating position. The job of an Oiler onboard is to assist ship engineers lubricating bearings and other moving parts of engines and other mechanical equipment aboard the ship. The oiler participates in the general maintenance of ship's main power plant, auxiliary engines and generators in order to ensure that oil temperature is 

within the standard limits and oil gauges are all working properly.

Wiper:

              The engine utility man / wiper is an entry level rating position within the engine department of the cruise ship. The engine utility man / wiper provides general assistance to licensed engineers and superior engine room ratings in different tasks in the engine room, such as general maintenance and repair of the various machinery and equipment, material handling equipment throughout the ship including elevators and winches, general cleaning and painting of the engine room, trash pick up, tools and instruments pick up and cleaning.

Fitter:

              Responsible for the maintenance and repair of all Fitting.

Motorman:

              Responsible for the daily maintenance and cleaning of specific engine parts as directed by the Chief Engineer.

  

Machinist:

             A machinist is a person who uses machine tools to make or modify parts, primarily metal parts, a process known as machining. This is accomplished by using machine tools to cut away excess material much as a woodcarver cuts away excess wood to produce his work. In addition to metal, the parts may be made of many other kinds of materials, such as plastic or wood products. The goal of these cutting operations is to produce a part that conforms to a set of specifications, or tolerances, usually in the form of engineering drawings commonly known as blueprints. 

Crew Members on Ships....

Crew members on ships-

1) DECK SIDE CREW MEMBER-

• Captain/Master
• Chief Officer/ Chief Mate
• Second Officer/ Second Mate
• Third officer/third mate
• Deck Cadet
• Bosun/ Boatswain
• ABLE BODIED SEAMAN (AB)
• ORDINARY SEAMAN (OS)

                                                                                                                                

• Captain/ Master:

           The captain or master is the ship's highest responsible officer, acting on behalf of the ship's owner. The caption is a licensed mariner in ultimate command of the vessel.

           The captain is legally responsible for the day-to-day affairs of the ship as he is in command. It is his responsibility to ensure that all the departments under him perform legally to the requirements of the ship's owner. The Captain represents the owner and hence is called "Master".

           A Ship's Captain, also called Shipmaster or Skipper, is responsible for its safe and efficient operation, including cargo operations, navigation, crew management and ensuring that the vessel complies with local and international laws, as well as company and flag state policies. The Captain is responsible for responding to and reporting in case of accidents and incidents, and in case of injuries and illness among the ship's crew and passengers.

           If the master of the ship is incapacitated or absent from the vessel, the “CHIEF OFFICER” is in charge of all the operations as he is the executive officer of the ship.

Chief Officer/ Chief Mate:

           The chief officer/first mate (often called the chief mate in the United States) is the head of the deck department on a merchant vessel, second-in-command after the ship's master. The chief mate's primary responsibilities are the vessel's cargo operations, its stability, and supervising the deck crew. The mate is responsible for the safety and security of the ship, as well as the welfare of the crew on board.

            The chief mate typically stands the 4-8 navigation watch. Additional duties include maintenance of the ship's hull, cargo gears, accommodations, the life saving appliances and the firefighting appliances. The Chief Mate also trains the crew and cadets on various aspects like safety, firefighting, search and rescue, and various other contingencies.

The chief officer assumes command of the whole ship in the absence or incapacitation of the master. In port and at sea, the chief mate is responsible to the captain for keeping the ship, crew, and cargo safe for eight hours each day. Traditionally, the chief mate stands a "4-8" watch: from 4am until 8am and 4pm until 8pm.

             The Chief Mate is generally responsible for the stability of the ship.
IMO regulations require the officer be fluent in English. This is required for a number of reasons, such as ability to use charts and nautical publications, to understand weather and safety messages, communicate with other ships and coast stations, and to be able to work with a multi-lingual crew.

Second Officer/ Second Mate:

             A second mate (2/M) or second officer is a licensed member of the deck department of a merchant ship. The second mate is the third in command and a watchkeeping officer, customarily the ship's navigator. Other duties vary, but the second mate is often the medical officer and in charge of maintaining distress signaling equipment. On oil tankers, the second mate usually assists the chief mate with the tank-cleaning operations.

             In port and at sea, the second mate is responsible to the captain for keeping the ship, its crew, and its cargo safe for eight hours each day.

             Traditionally, the second mate stands a "12-4" watch: from midnight until 4am and noon until 4pm.

Third officer/third mate:

            A Third Mate (3/M) or Third Officer is a licensed member of the deck department of a merchant ship. The third mate is a watchstander and customarily the ship's safety officer. Other duties vary depending on the type of ship, its crewing, and other factors.

Duties related to the role of safety officer focus on responsibility for items such as firefighting equipment, lifeboats, and various other emergency systems.
            In port and at sea, the third mate is responsible to the captain for keeping the ship, its crew, and its cargo safe for eight hours each day. Traditionally, the third mate stands an "8-12" watch: from 8am until 12 noon and 8pm until midnight.

Deck Cadet:

            A Deck cadet is an officer under training in much the same way as in a military context. Cadets receive training in firefighting, first aid and survival techniques. Deck Cadets train in the fields of navigation, ship handling and cargo handling as well as maritime law. A cadet reports to the Chief Officer. His or her role as a trainee is to observe and learn, while helping out where possible, mostly the Chief Officer. As they do not have Certificate of Competency, cadets cannot hold a watch, but will likely assist one of the qualified officers, often with the Chief Officer, with their watch.

Bosun/ Boatswain:

            A bosun is an unlicensed member of the deck department of a merchant ship. The boatswain supervises the other unlicensed members of the ship's deck department, and typically is not a watchstander.

            The bosun works in a ship's deck department as the foreman of the unlicensed deck crew.  A bosun must be highly skilled in all matters of seamanship required for working on deck of a seagoing vessel. The bosun is distinguished from other able seamen by the supervisory roles: planning, scheduling, and assigning work.

            A bosun will have knowledge of and ability to use knots, hitches, bends, whipping, and splices as needed to perform tasks such as mooring a vessel. Competencies extend to the safe operation of a windlass. Duties may require operating the basic functions of a windlass, including letting go and heaving up an anchor. Moreover, a bosun may be called upon to lead firefighting efforts or other emergency procedures encountered in the inherently dangerous environment of a ship.

ABLE BODIED SEAMAN (AB):

            An Able Seaman (AB) is an unlicensed member of the deck department of a merchant ship. An AB may work as a watchstander, a day worker, or a combination of these roles.

            At sea an AB watchstander's  duties include standing watch as helmsman and lookout. A helmsman is required to maintain a steady course, properly execute all rudder orders and communicate utilizing navigational terms relating to heading and steering. A watchstander may be called upon to stand security-related watches, such as a gangway watch or anchor watch while the ship is not underway.

ORDINARY SEAMAN (OS):

            An Ordinary Seaman (OS) is an unlicensed member of the deck department of a merchant ship. The position is an apprenticeship to become an Able Seaman, and has been for centuries. In modern times, an OS is required to work on a ship for a specific amount of time, gaining what is referred to as "sea time." Once a sufficient amount of sea time is acquired, the OS can apply to take a series of courses, and then a series of examinations to become certified as an able seaman.

            An OS is generally not required to stand watch, but must pass examinations on watchstanding skills such as performing lookout duty and being a helmsman. Thus an OS will often be found on a ship's bridge after working hours taking a turn at the ship's wheel or being familiarized with bridge equipment.