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Seafaring A – Z Alphabet – “V” is for…


Seafaring “V” is for…

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Vapours – Tankers, despite safety advances, still have the capacity to act as floating bombs. This is due to the “fire triangle”, and the fact that before a fire or explosion can occur, three conditions must be met simultaneously.

A fuel (ie. combustible gas) and oxygen (air) must exist in certain proportions, along with an ignition source, such as a spark or flame. The ratio of fuel and oxygen that is required varies with each combustible gas or vapour.

The minimum concentration of a particular combustible gas or “vapour” necessary to support its combustion in air is defined as the Lower Explosive Limit (LEL) for that gas. Below this level, the mixture is too “lean” to burn. The maximum concentration of a gas or vapour that will burn in air is defined as the Upper Explosive Limit (UEL). Above this level, the mixture is too “rich” to burn. The range between the LEL and UEL is known as the flammable range for that gas or vapour.

Controlling gas and vapour concentrations outside the explosive limits is a major consideration in tanker safety. The limits vary with temperature and pressure and the type of cargo being carried, and crews need to be aware of the different needs of each cargo, and the acceptable limits maintained in the tanks.

Methods used to control the concentration of a potentially explosive gas or vapour include use of inert gases, which sees the use of an unreactive gas such as nitrogen or argon used to dilute the explosive gas before coming in contact with air. Use of scrubbers or adsorption resins to remove explosive gases before release are also common, and the gases are then vented from the tanks.

Cargo vapour displaced from tanks during loading or ballasting should be vented through the installed venting system to atmosphere, except when return of the vapour to shore is required. The cargo or ballast loading rate should not exceed a rate of vapour flow within the capacity of the installed system. The cargo tank venting system should be set for the type of operation to be performed.

Tank vent system outlets are located at a safe distance from all areas where personnel who are not involved in cargo work may be present, to ensure that toxic vapours are diluted to a safe level of concentration before they can reach such an area. The safe distances specified depend on the cargo, but in all cases the principles described in the IMO Codes will have been met by the ship’s design.

VHF Radio

VHF radio

Very High Frequency (VHF) Radio – Marine radio was first installed on ships around the turn of the 20th century. In those early days, radio was used primarily for transmission and reception of passenger telegrams.

Radio watchkeeping hours were not standardised, and there was no regulatory requirement for carriage of radio by ships. Indeed, there was a general lack of regulation of the radio spectrum. This was set to change after the loss of the “RMS Titanic” in April 1912.

During the 1920’s, 30’s and 40’s, marine radio advanced with the technology of the day – radiotelephone operation was introduced, and most importantly, High Frequency (HF) came into widespread use, thereby allowing communications over ever-increasing distances. “Talk between Ships” was the established radio network the American warships used to communicate with each other.

Today marine communications come under the Global Maritime Distress and Safety System (GMDSS), an international system which uses improved terrestrial and satellite technology and ship-board radio systems.

Pre-GMDSS marine radio equipment was required to provide operation over a minimum specified range of 150 nautical miles. The pre-GMDSS systems were, in reality, based on 1920’s technology and one of the principal advantages of GMDSS is that the system is actually an amalgam of various individual radio systems, both terrestrial and satellite.

Marine VHF radio refers to the radio frequency range between 156.0 and 162.025 MHz, inclusive. The “VHF” signifies the very high frequency of the range. In the official language of the International Telecommunication Union the band is called the VHF maritime mobile band.

Marine VHF radio equipment is used for a wide variety of purposes, including summoning rescue services and communicating with harbours, locks, bridges and marinas. The equipment or “set” is a combined transmitter and receiver and only operates on standard, international frequencies known as channels.

Each of these VHF channels has a specific purpose, In the United Kingdom there are approximately 57 VHF channels available plus the private channels M and M2 for use by marinas and yacht clubs and the private channel 00 which is for HMCG use only. 2 additional channels are dedicated to the Automatic Identification System (AIS) services.

CH16 is the only portion of the VHF spectrum truly allocated as “maritime”. Channel 16 VHF (156.8 MHz) is the marine VHF radio frequency used for shipping and maritime purposes, to call up ships and shore stations, and as an international distress frequency.

Channel 16 is used for broadcasting distress calls such as mayday, pan-pan, securité or other urgent safety messages. Some nations allow the use of marine VHF 16 as an initial calling frequency; after an initial response the call is to be switched to one of the working channels, except in case of emergency traffic.

VHF channel 16 is monitored 24 hours a day by coast guards around the world. In addition, all sea bound vessels are advised to monitor channel 16 VHF when sailing, except when communicating on other marine channels for legitimate business or operational reasons.

Obscene or objectionable language, transmission of music, and subversive messages are forbidden. Though as anyone who has ever listened to VHF traffic will know that there is quite a lot of exactly this kind of “chatter”.



Very Large Ore Carrier (VLOC) – A bulk carrier, bulk freighter, or bulker is a commercial ship specially designed to transport unpackaged bulk cargo, such as grains, coal, ore, and cement in its cargo holds. Since the first specialised bulk carrier in 1852, they have evolved and been specially designed to maximise capacity, efficiency, and durability.

This has not been without safety concerns and issues with construction. Bulk cargo can be very dense, corrosive, or abrasive. This can present safety problems: cargo shifting, spontaneous combustion, and cargo saturation can threaten a ship. The use of ships that are old and have corrosion problems has been linked to a spate of bulk carrier sinkings in the 1980 and 90s, as have the bulker’s large hatchways, important for efficient cargo handling.

Today, bulk carriers make up much of the world’s merchant fleets, in the region of 20% of vessels are classed as bulk carriers, and range in size from single-hold mini-bulkers to mammoth ore ships able to carry 400,000 metric tons of deadweight (DWT).

These giant vessels are called “VLOC,” “VLBC,” “ULOC,” and “ULBC” for very large and ultra large ore and bulk carriers were adapted from designations used for “supertankers”, these being very large crude carrier (VLCC) and ultra large crude carrier (ULCC).

The trend to build a fleet of very large ore carriers (VLOC) was started by the Brazilian mining company Vale S.A. These were owned or chartered to carry iron ore from Brazil to European and Asian ports. With a capacity ranging from 380,000 to 400,000 tons deadweight, the vessels meet the “Chinamax” standard of ship measurements for limits on draft and beam.

The Vale ships, or “Valemax ships” as they became known are the largest bulk carriers ever constructed, when measuring deadweight tonnage or length overall, and are amongst the longest ships of any type currently in service. They have not been without their problems, however, with talk of commercial or political problems and even some construction after one began to sink during loading.

The current incarnation of VLOCs are 360 to 362 metres long, making them some of the longest ships currently in service. With a maximum draught of between 22 and 23 metres while loaded, the ships are limited only to a few deepwater ports in Brazil, Europe and China. In ballast the ships draw around 12 metres of water. The beam of the Valemax ships is about 65 metres, making them the largest bulk carriers ever built.

The Valemax vessels have seven cargo holds with a total gross volume of almost 220,000 cubic metres. In addition to increasing the strength of the hull special attention has also been paid to improve the speed and efficiency of the loading and discharging operations. Each cargo hold can be fully loaded by a shiploader in a single step with a loading rate of 13,500 tonnes per hour and can carry almost as much iron ore as a small Panamax carrier.

Like most modern bulk carriers, Valemax vessels are powered by a single two-stroke low-speed crosshead diesel engine directly coupled to a fixed-pitch propeller. The new ships are considerably larger than the previous record holder, 364,767-ton “Berge Stahl”, which had been the largest bulk carrier in the world since it was built in 1986.



Vetting – Ship Vetting is a risk assessment process carried out by charterers and terminal operators in order to avoid making use of deficient ships or barges when goods are being transported by sea.

The Shipowner / operator is responsible for the condition and operation of ship, so those seeking to use it want to have reassurance on the state of the ship, and the way in which the vessel is managed. Those who use ships, be they a chartering company, shipping company or a terminal depot, need to manage all safety, quality and environmental risks carefully. These “users”, need to ensure compliance with stringent legislation.

There are real risks from using substandard ships, so to operate efficiently and minimise liability, charterers and all industry players must take all “reasonable steps” to ensure ships are being properly operated and are in a suitable condition to complete a voyage safely. The problems of substandard ships and shipping companies are many fold, but as a minimum could include:

• casualties – minor delays through to total loss, which carry severe human, environmental and commercial costs
• undue delays and costs while the ship is inspected in port
• falling foul of regulators
• rising insurance costs

Ship vetting involves sourcing data on ships and evaluating the potential risks such as the ship’s structural integrity, competence of owners, managers and crew, past casualties and incidents. The Vetting Inspection is simply an inspection i.e. a “snap shot in time”, and for vetting purposes a vessel does not pass or fail an inspection, but an inspection of the vessel forms an obvious and important part of the overall screening process.

When in the late sixties a large crude oil carrier grounded and spilled cargo, the oil industry decided to take action to safeguard the quality and safety standards of the ships transporting its cargoes in order to avoid similar accidents. This triggered the creation of ship vetting departments within the oil companies and the development of industry ship inspection programmes. This initiative was taken up by the chemical industry as part of its Responsible Care programme.

Experience from past accidents clearly indicates that in case of an accident the focus is not only on the ship owners, but more and more on those owning the cargo. Courts requested shippers to demonstrate that before accepting the nomination of the ship, they did everything within their power to ensure that the shipment could be performed in a safe way. It is therefore recommended that every chemical company develops a ship vetting system, including the setting of minimum safety standards, the collection of appropriate data and an adequate assessment of these data before chartering a ship.

Accident statistics and inspection results demonstrate that substandard ships continue to trade, emphasising a continued need for chemical companies to have efficient ship vetting systems in place.

Vetting Inspections are a skilled undertaking, and so there are experts who specialise in assessing the levels of risk potentially posed by a vessel. Inspections may be undertaken by:

• Individual oil/chemical companies or terminals
• Accredited SIRE inspectors under the SIRE system
• Accredited CDI inspectors under the Chemical Distribution Institute (CDI) system

Many companies involved in the hire of ships rely heavily on the Oil Companies International Marine Forum (OCIMF), Ship Inspection Report Programme (SIRE). The SIRE Programme is a unique tanker risk assessment tool, and contains a very large database of up-to-date information about tankers and barges.

Voyage – The UK Merchant Shipping (Safety of Navigation) Regulations 2002 categorise a number of different types of vessel voyages. These include:

• “Domestic voyage” which means a voyage in sea areas from a port of a member State or EEA State to the same or another port within that member State or EEA State;
• “International voyage” means a voyage from a country to which the 1974 SOLAS Convention applies to a port outside that country, or conversely;
• “Long international voyage” means an international voyage which is not a short international voyage;

Whatever the voyage type, it is necessary for “voyage planning” to take place, and navigators must develop a complete detailed strategy of a vessel’s voyage from start to finish, or “berth to berth”.

The plan includes leaving the dock and harbour area, the en route portion of a voyage, approaching the destination, and mooring.

The practice of voyage planning has evolved from pencilling lines on nautical charts and listing alterations of course, to a far more evolved and involved process of risk management.

Having and using a voyage plan is, “of essential importance for safety of life at sea, safety and efficiency of navigation and protection of the marine environment, and is necessary for all types of vessels on all types of voyages.

The guidance is contained within IMO Resolution A.893 (21), “Guidelines for Voyage Planning”. Which is to be followed on all vessels. This states the master and officers should appraise all relevant information, plan the intended voyage, execute the plan taking account of prevailing conditions and ensure they monitor the vessel’s progress against the plan continuously.

Voyage Charter – Chartering is an activity within the shipping industry. In some cases a charterer may own cargo and employ a shipbroker to find a ship to deliver the cargo for a certain price, called freight rate.

Freight rates may be on a per-ton basis over a certain route (e.g. for iron ore between Brazil and China), in Worldscale points (in case of oil tankers) or alternatively may be expressed in terms of a total sum – normally in U.S. dollars – per day for the agreed duration of the charter.

A charter party, from the Latin: “charta partita”; a legal paper or instrument, divided, i.e. written in duplicate so that each party retains half, a written, or partly written and partly printed, contract between a shipowner and a merchant, by which a ship is let or hired for the conveyance of goods on a specified voyage, or for a defined period. A vessel might also be chartered to carry passengers on a journey.

The contract between the owner of a vessel sees the take over the vessel for either a certain amount of time (a time charter) or for a certain point-to-point voyage (a voyage charter), giving rise to these two main types of charter agreement.

A charterer may also be a party without a cargo who takes a vessel on charter for a specified period from the owner and then trades the ship to carry cargoes at a profit above the hire rate, or even makes a profit in a rising market by re-letting the ship out to other charterers.

Depending on the type of ship and the type of charter, normally a standard contract form called a charter party is used to record the exact rate, duration and terms agreed between the shipowner and the charterer.

A voyage charter is the hiring of a vessel and crew for a voyage between a load port and a discharge port. The charterer pays the vessel owner on a per-ton or lump-sum basis. The owner pays the port costs (excluding stevedoring), fuel costs and crew costs. The payment for the use of the vessel is known as freight. A voyage charter specifies a period, known as laytime, for loading and unloading the cargo. If laytime is exceeded, the charterer must pay demurrage. If laytime is saved, the charter party may require the shipowner to pay despatch to the charterer.

Voyage Data Recorder – Whenever a plane crashes, much is made of the search for the “black box” – which records details of the plane’s activities. Ships are fitted with a similar system, known as the “Voyage data recorder” or “VDR”.

The VDR, is a data recording system designed for all vessels required to comply with the IMO’s International Convention SOLAS Requirements (IMO Res.A.861 (20)) in order to collect data from various sensors on board the vessel. The VDR then stores this information in an externally mounted protective storage unit. The protective storage unit is a tamper-proof unit designed to withstand the extreme shock, impact, pressure and heat, which could be associated with a marine accident (fire, explosion, collision, sinking, etc.).

Just like the black boxes carried on aircraft, VDRs enable accident investigators to review procedures and instructions in the moments before an incident and help to identify the cause of any accident.

There are various sensors placed on bridge of the ship and on prominent location from which the required data is continuously collected. This collected data which comprises of voices, various parameters, ships location etc. are then fed to a storage unit where the whole input is recorded and saved for at least12 hours.

The protective storage unit may be in a retrievable fixed unit or free float unit (or combined with EPIRB) when the ship sinks. The last 12 hours of stored data in the protected unit can be recovered and replayed by the authorities or ship owners for incident investigation.

Aside from accident investigation, there can be other uses of recorded data for preventive maintenance, performance efficiency monitoring, heavy weather damage analysis, accident avoidance and training purposes to improve safety and reduce running costs.

The mandatory regulations are contained in chapter V on Safety of Navigation of the International Convention for the Safety of Life at Sea, 1974 (SOLAS). Performance standards for VDRs were adopted in 1997 and the information recorded includes the following information:

• Position, date, time using GPS
• Speed log – Speed through water or speed over ground
• Gyro compass – Heading
• Radar – As displayed or AIS data if no off-the-shelf converter available for the Radar video
• ECDIS – A screen capture every 15 seconds and a list of navigational charts in use every 10 minutes or when a chart change occurs
• Audio from the bridge, including bridge wings
• VHF radio communications
• Echo sounder – Depth under keel
• Main alarms – All IMO mandatory alarms
• Hull openings – Status of hull doors as indicated on the bridge
• Watertight & fire doors status as indicated on the bridge
• Hull stress – Accelerations and hull stresses
• Rudder – Order and feedback response
• Engine/Propeller – Order and feedback response
• Thrusters* – Status, direction, amount of thrust % or RPM
• Anemometer and weather vane – Wind speed and direction
• Data marked with may not be recorded in S-VDR, except Radar and Echo Sounder if data & standard interfaces available.