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Seafaring A-Z Alphabet – “M” is for…


Seafaring “M” is for…

Let’s get this rolling with:

Magnetic Compass

Magnetic compass

Magnetic Compass – People have been navigating with magnetic compasses for the best part of 900 years. The magnetic compass was first invented as a device for divination as early as the Chinese Han Dynasty (since about 206 BC), and later adopted for navigation by the Song Dynasty Chinese during the 11th century. The first usage of a compass recorded in Western Europe and Persia occurred around the early 13th century.

The magnetic compass functions as a pointer to “magnetic north”, the local magnetic meridian, because the magnetised needle at its heart aligns itself with the horizontal component of the Earth’s magnetic field. The simplest compass is a magnetized metal needle mounted in such a way that it can spin freely.

In magnetism, “like poles repel, unlike poles attract” – which is key to a magnetic compass: the red pointer in a compass is a magnet and it’s being attracted by Earth’s own magnetism. The magnetic field exerts a torque on the needle, pulling one end or pole of the needle approximately toward the Earth’s North magnetic pole, and pulling the other toward the South magnetic pole.

In essence, the Earth behaves like a giant bar magnet with one pole up in the Arctic (near the north pole) and another pole down in Antarctica (near the south pole). Now if the needle in your compass is pointing north, that means it’s being attracted (pulled toward) something near Earth’s north pole.

Earth’s magnetic field is actually quite weak compared to gravity and friction, so for a compass to show the effects of Earth’s magnetism, the effects of other forces need to be reduced. That’s why compass needles are lightweight (so gravity has less effect on them) and mounted on frictionless bearings (so there’s less frictional resistance for the magnetic force to overcome).There are some important flaws to remember, these are called declination and deviation.

Declination is the difference between “magnetic north” and “true north”, an angle that varies slightly from place to place, and from year to year, because the position of Earth’s magnetic north is constantly changing. In navigation we take the declination into account and correct for it.

Deviation is the effect of other materials, particularly metal, on the compass. These can make a significant difference. Deviation is the angle between where the compass would point if it were perfectly accurate (magnetic north) and where it actually points. If there’s a magnet nearby, or you’re near a particularly magnetic bit of Earth’s crust, or there are fluctuating electric currents generating magnetic fields, your compass needle is going to be affected and its accuracy is going to be reduced.

Declination and deviation don’t matter so much if you’re on foot with a map but on a ship, far from land and in bad weather (so you can’t navigate by the sky), it’s a different story. That’s why ship’s compasses are more sophisticated than ones typically used on land.

In a modern ship’s compass, the compass card is attached to a float with a number of magnetic needles underneath it and spins freely inside a large glass bowl filled with a mixture of alcohol and water (to minimize friction and absorb vibrations from the moving ship). The whole thing is mounted on gimbals (pivots) in a stand called a binnacle so it stays horizontal even when the ship is pitching (moving up and down) and rolling (rocking from side to side) in the waves.



Maritime Labour Convention – The Maritime Labour Convention 2006 (MLC) is an International Labour Organization (ILO) convention established in 2006 as the “fourth pillar” of international maritime law. The other “pillars are the SOLAS, STCW and MARPOL.

MLC has brought together legislation relating to labour and seafarers. As such it embodies the various standards of existing international maritime labour Conventions and Recommendations, as well as the fundamental principles to be found in other international labour Conventions.

The convention entered into force on 20 August 2013. As of the August 2016, the convention has been ratified by 77 states representing over 87 per cent of global shipping.

Even though there are still vessels under non signatory flags, this does not really matters as they still need to comply when they attempt to enter ports of signatory States. This is termed the, “no more favourable treatment” for ships of non-ratifying countries. This, in theory, acts to ensure a level playing field.

The convention consists of the sixteen articles containing general provisions as well as the Code. The Code consists of five Titles, these are:

Title 1: Minimum requirements for seafarers – It addresses issues such as minimum age requirements: the mimimum age is 16 years (18 for night work and work in hazardous areas). It also covers medical fitness, training and recruitment.

Title 2: Employment conditions – here are listed the conditions of the contract and payments, as well as the working conditions on ships. Contracts should be clear, legally enforceable and incorporate collective bargaining agreements, while wages should be paid at least every month, and should be transferrable regularly to family if so desired. It also covers manning levels, rest hours, leave and repatriation.

Title 3: Accommodation, Recreational Facilities, Food and Catering, specifies rules detailed rules for accommodation and recreational facilities, as well as food and catering.

Title 4: Health Protection, Medical Care, Welfare and Social Security Protection, contains regulations about Health, Liability, Medical care, Welfare and Social security – also medical care on board ship and ashore.

Another vital issue is that of shipowners’ liability – so that seafarers are protected from the financial effects of “sickness, injury or death occurring in connection with their employment”. This includes at least 16 weeks of payment of wages after start of sickness.

An important operational issue is covered in Title 4 – as health and safety protection and accident prevention is covered. The key issue is that seafarers should be provided with a safe and hygienic environment during work and rest.

There is also the issue of access to shore-based welfare facilities. Port states should provide “welfare, cultural, recreational and information facilities and services” and to provide easy access to these services. This is still massively problematic, as it seems clear from the Crewtoo Seafarers Happiness Index, and from many other sources, that the problems of access to shoreleave are not being adequately addressed.

Title 5: Compliance and Enforcement, sets standers to ensure compliance with the convention. The title distinguishes requirements for flag states and port states.

MLC imposes rules and also responsibilities on flags. Flag States are responsible for ensuring implementation of the rules on the ships that fly its flag. While port States are responsible for inspection of a Certificate of Maritime Compliance or to see if the vessel would comply.

As with many other major codes and conventions before it, there were concerns that the entry into force would bring ships to a halt. This hasn’t happened – and in some senses there has not been a major effect yet. However, it is felt that this is coming – there are likely to be more vessels detained, and certainly the issue of crew wages and financial security will come to a head in the coming years. Find out more–en/index.htm



Meteorology – Meteorology is the interdisciplinary scientific study of the atmosphere. Meteorology, climatology, atmospheric physics, and atmospheric chemistry are sub-disciplines of the atmospheric sciences.

The word “meteorology” is from Greek “high (in the sky)”, i.e. “the study of things in the air”. Meteorology and hydrology compose the interdisciplinary field of hydrometeorology. The interactions between Earth’s atmosphere and its oceans are part of a coupled ocean-atmosphere system. Meteorology has application in many diverse fields such as the military, energy production, transport, agriculture, and construction.

Meteorological phenomena are observable weather events that are explained by the science of meteorology, and are described and quantified by the variables of Earth’s atmosphere: temperature, air pressure, water vapour, mass flow, and the variations and interactions of the study of meteorology dates back millennia, though significant progress in meteorology did not occur until the 18th century when the laws of physics were beginning to be founded – the next leap came with the development of the computer.

Computers allow for the automated solution of the great many equations that model the weather, in the latter half of the 20th century that significant breakthroughs in weather forecasting were achieved.

For sailing ships the wind was of obvious concern – and sailors developed all kinds of forecasting techniques. Nowadays vessels aren’t becalmed or left waiting for a favourable wind, but weather still matters a great deal to the modern mariner.

While forecasting has improved, the effect of weather can still be felt, indeed according to BIMCO “heavy weather” is still responsible for some 30% of ship losses and its avoidance is still an important part of the seafarer’s science.

The global supply chain is dependent on a good understanding of the weather – shipping companies and masters need to know what is to be encountered on a voyage, minimising the time spend ploughing into head winds and seas that slow down even the most powerful ships and increase fuel consumption.

The strategic avoidance of bad weather depends on a good understanding of meteorology, and of course, the accuracy of the weather forecasts. Route optimisation is of paramount importance for maritime safety and the bottom line profitability of each and every voyage.

Even the biggest ships need to respect the weather. Ultra Large Containers Vessels, with their mammoth high deck stacks need to be able to avoid heavy weather, especially during the North Atlantic and North Pacific Winters. While cruise passengers, in particular, don’t feel they are getting their money’s worth if they are seasick – so they need to keep a “weather eye” on conditions.

While meteorological services are reliant upon powerful computers and satellites there is a still a very important role for the surface weather reports from ships to inform them about the probable behaviour of the weather.

Weather reporting ships, which are ordinary merchant ships on passage with an auxiliary weather reporting role, will normally provide a six-hour report of the weather they are encountering, detailing such important features as wind speed and direction, temperature, pressure, cloud cover and sea state In those areas where tropical revolving storms might be encountered, the mariner meets the weather at its worst, and even large modern ships have been overwhelmed, so an appreciation of the weather, and hour by hour forecasts, are essential if the storm is to be accurately tracked and ships kept safe. Lives may depend upon good meteorology.



Mooring – A mooring refers to any permanent structure to which a vessel may be secured. Examples include quays, wharfs, jetties, piers, anchor buoys, and mooring buoys.

A ship is secured to a mooring to prevent movement of the ship on the water. As a verb, mooring refers to the act of attaching a vessel to a mooring. The term probably stems from the Dutch verb “meren” (to moor), which has been used in English since the end of the 15th century.

Mooring lines are passed from the vessels to shore, and once a mooring line is attached to a bollard, it is pulled tight. Large ships generally tighten their mooring lines using heavy machinery called mooring winches or capstans.

Mooring ropes, lines or hawsers are fixed to deck fittings on the vessel at one end and to fittings such as bollards, rings, and cleats on the other end. Mooring lines are usually made from nylon or polypropylene. These are easy to work with and last for years, while being highly elastic. This elasticity has advantages and disadvantages. The main advantage is that during an event, such as a high wind or the close passing of another ship, stress can be spread across several lines. However, should a highly stressed nylon line break, it may part catastrophically, causing snapback, which can fatally injure bystanders.

The effect of snapback is like stretching a rubber band to its breaking point between your hands and then suffering a stinging blow from its suddenly flexing broken ends. Seafarers often suffer from mooring injuries, and the effects of a snapback can be deadly. A blow from a heavy mooring line can inflict severe injuries or even sever limbs.

Though there are far more technologically advanced fibres too, such as dyneema which are increasingly popular. These are ultra-high molecular weight polyethylene (UHMwPE), and have incredible strength and are less elastic – so not as dangerous.

Some ships use wire rope for one or more of their mooring lines. Wire rope is hard to handle and maintain. There is also risk associated with using wire rope on a ship’s stern in the vicinity of its propeller.

A typical mooring scheme uses a “head line” which keeps the forward part of the ship against the dock, then a forward “breast Line” to keep pulled into close to the berth. This is then followed by a “Forward Spring” which is used to prevent forward motion. This set-up is replicated at the stern, with an aft spring, aft breast line and stern line.



Master – A ship’s master is a licensed mariner in ultimate command of the merchant vessel, also known as the “Captain”.

Only the senior officer onboard will be termed Captain or Master – but others onboard can hold a “Master Mariner” certificate. This is the professional qualification required for someone to serve as the Captain of a commercial vessel of any size, of any type, operating anywhere in the world. It is usual practice for the Chief Officer to be qualified to take command in the event something happens to the Captain, so they would be expected to be qualified as Master.

In many countries, the term “Master Mariner” is reserved only for those who hold an unlimited master’s certificate. The term “unlimited” (often referred to as unrestricted) indicates that there are no limits on size, power or geographic location on the certificate. It is the highest level of professional qualification amongst mariners and Deck Officers.

The term master mariner has been in use at least since the 13th century, reflecting the fact that in guild or livery company terms, such a person was a master craftsman in this specific profession (e.g. master Carpenter, master Blacksmith). In the United States, the term was introduced in the mid-19th century.

The captain is ultimately responsible for the safe and efficient operation of the ship, including: seaworthiness, ship’s safety and security conditions, cargo operations, navigation, crew management and ensuring that the vessel complies with local and international laws, as well as company and flag state policies. All persons on board, particularly during navigation, including, public authorities, state authorities, officers and crew, other shipboard staff members, passengers, guests and pilots, are under the captain’s authority and are his or her ultimate responsibility.

A ship’s captain commands and manages all ship’s personnel, and is typically in charge of the ship’s accounting, payrolls, and inventories too – this is more prevalent since the demise of the Purser role on most ships. So on ships without a purser, the captain is in charge of the ship’s accounting. This includes ensuring an adequate amount of cash on board, coordinating the ship’s payroll (including draws and advances), and managing the ship’s slop chest.

The captain ensures that the ship complies with local and international laws and complies also with company policies. The captain is ultimately responsible, under the law, for aspects of operation such as the safe navigation of the ship, its cleanliness and seaworthiness, safe handling of all cargo, management of all personnel, inventory of ship’s cash and stores, and maintaining the ship’s certificates and documentation.

There is also responsibility for satisfying requirements of the local immigration and customs officials. Immigration issues can include situations such as embarking and disembarking passengers, handling crewmembers who desert the ship, making crew-changes in port, and making accommodations for foreign crewmembers. Customs requirements can include the master providing a cargo declaration, a ship’s stores declaration, a declaration of crewmembers’ personal effects, crew lists and passenger lists.

The captain has special responsibilities when the ship or its cargo are damaged, when the ship causes damage to other vessels or facilities, and in the case of injury or death of a crewmember or passenger. The master acts as a liaison to local investigators and is responsible for providing complete and accurate logbooks, reports, statements and evidence to document an incident.

Away from commercial shipping, the master, or sailing master, was a historic term for a naval officer trained in and responsible for the navigation of a sailing vessel. The rank can be equated to a professional seaman and specialist in navigation, rather than as a military commander.

In the British Royal Navy, the master was originally a warrant officer who ranked with, but after, the lieutenants. The rank became a commissioned officer rank and was renamed to navigating lieutenant in 1867; the rank gradually fell out of use from around c1890 since all lieutenants were required to pass the same exams.

The term master came from the Latin language used during the imperial Roman age, from the old Roman term “magister navis”, that is, the nobleman patrician designated as maximum authority on board the vessel.



Marpol – MARPOL 73/78 is the International Convention for the Prevention of Pollution from Ships, 1973 as modified by the Protocol of 1978. (“MARPOL” is short for marine pollution and 73/78 short for the years 1973 and 1978.)

MARPOL 73/78 is one of the most important international marine environmental conventions. It was developed by the International Maritime Organization in an effort to minimise pollution of the oceans and seas, including dumping, oil and air pollution.

The objective of this convention is to preserve the marine environment in an attempt to completely eliminate pollution by oil and other harmful substances and to minimize accidental spillage of such substances.

The original MARPOL was signed on 17 February 1973, but did not come into force at the signing date. The current convention is a combination of 1973 Convention and the 1978 Protocol. It entered into force on 2 October 1983. As of April 2016, 154 states, representing 98.7 per cent of the world’s shipping tonnage, are state parties to the convention.

All ships flagged under countries that are signatories to MARPOL are subject to its requirements, regardless of where they sail and member nations are responsible for vessels registered under their respective nationalities.

The Convention includes regulations aimed at preventing and minimizing pollution from ships – both accidental pollution and that from routine operations – and currently includes six technical Annexes. Special Areas with strict controls on operational discharges are included in most Annexes.

MARPOL includes regulations aimed at preventing and minimising, both accidental and operational, pollution from ships and currently includes six technical Annexes:

• Annex I Regulations for the Prevention of Pollution by Oil
• Annex II Regulations for the Control of Pollution by Noxious Liquid Substances in Bulk
• Annex III Prevention of Pollution by Harmful Substances Carried by Sea in Packaged Form
• Annex IV Prevention of Pollution by Sewage from Ships
• Annex V Prevention of Pollution by Garbage from Ships
• Annex VI Prevention of Air Pollution from Ships

New requirements to MARPOL Annex I, regulating Ship-to-ship (STS) transfers, came into effect on January 1 2011. Ship-to-ship (STS) oil-cargo transfers at sea are a common feature of the tanker trades, and preventing spills and helping to ensure safety has long been an industry priority.

The convention requires that vessels have a “Shipboard Oil Pollution Emergency Plan (SOPEP)”. Every oil tanker of 150 gross tonnage and above and every ship other than an oil tanker of 400 gross tonnage and above shall carry on board a SOPEP approved by their flag State.

Marpol has also introduced “Special Areas”. Sea area where because of oceanographical and ecological condition and the amount of maritime traffic the special methods for the prevention of sea pollution by oil are needed.

Special areas are:

• Mediterranean Sea area;
• Baltic Sea area;
• Black Sea area;
• Red Sea area;
• Gulfs area;
• Gulf of Aden area;
• Antarctic area;
• North West European waters (these include the North Sea and its approaches, the Irish Sea and its approaches, the Celtic Sea, the English Channel and its approaches and part of the North East Atlantic immediately to the west of Ireland);
• Oman area of the Arabian Sea.
• Southern South African waters



Medical – The International Maritime Organization’s (IMO) International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (STCW), 1978, as amended, states that every seafarer holding a certificate issued under the provisions of the Convention, who is serving at sea, shall also hold a valid medical certificate issued in accordance with the provisions of Regulation I/9 and of Section A-I/9 of the STCW Code.

So, seafarers are required to undergo medical examinations to reduce risks to other crew members and for the safe operation of the ship, as well as to safeguard their personal health and safety.

The MLC, 2006, and the STCW Convention, 1978, as amended, require a seafarer to hold a medical certificate, detail the information to be recorded and indicate certain specific aspects of fitness that need to be assessed.

The aim of the medical examination is to ensure that the seafarer being examined is medically fit to perform his or her routine and emergency duties at sea and is not suffering from any medical condition likely to be aggravated by service at sea, to render him or her unfit for service or to endanger the health of other persons on board.

Wherever possible, any conditions found should be treated prior to returning to work at sea so that the full range of routine and emergency duties can be undertaken. If this is not possible, the abilities of the seafarer should be assessed in relation to his or her routine and emergency duties and recommendations made on what the seafarer is able to do and whether any reasonable adjustments could enable him or her to work effectively.

In some cases, problems will be identified that are incompatible with duties at sea and cannot be remedied. Appendices A–E provide information on the disabilities and medical conditions which are not likely to prevent all routine and emergency duties being performed, those which require adaptation or limitation to routine and emergency duties, and those which result in either short-term or longer term unfitness to work at sea.

The medical certificate is neither a certificate of general health nor a certification of the absence of illness. It is a confirmation that the seafarer is expected to be able to meet the minimum requirements for performing the routine and emergency duties specific to their post at sea safely and effectively during the period of validity of the medical certificate.

The examining medical practitioner should base the decision to issue a medical certificate on whether criteria for minimum performance requirements, as listed in the appendices to this document, are met in the following areas:

• Vision (Appendix A),
• Hearing (Appendix B)
• Physical capabilities (Appendix C);
• Impairment from the use of medication (Appendix D);
• Presence or recent history of an illness or condition (Appendix E).