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


Seafaring “U” is for…

Let’s get this rolling with:

Ullage – The “Ullage” or “headspace” of a tank or vessel is the unfilled space left to be filled, and describes the empty space in large tanks or holds used to store or carry liquids –usually oil, but can be applied to bulk solids such as grain.

Taking an ullage reading is the companion process to taking a “sounding”. However, where a sounding measures the depth of fluid from the surface to the bottom of the tank, an ullage value is the distance yet to be filled.

Ullage measurements relate to the void space in the tank measured from the top of the tank to the upper surface of the fluid. Such readings can be taken in pressurised tanks, cargo holds and also ballast tanks.

The taking of an ullage is important in different ways depending on the type of tank. For ballasting it can give an indication of how long it will take to complete filling a tank. While for cargo holds it can be especially important and even be relevant to stability; liquid or dry bulk cargo in a part-filled hold can shift asymmetrically towards one side as the ship heels to one side and the other, reducing the margin of stability when compared with a full hold. Excessive ullage in a tank may contribute to the free surface effect. When referring to the free surface effect, the condition of a tank that is not full is described as a “slack tank”, while a full tank is “pressed up”.

So it becomes vital to know how much of the tanks remains to be filled. For bunkering it is also vital to know how much fuel is loaded into the bunker tank. While sounding can be used to quantify the quantity of liquid present, ullaging can be cleaner and quicker.

Ullage readings can also be important when it comes to gases or vapour in pressurised tanks. In accordance with IMO regulations, the Code of Federal Regulations, and Classification Society rules, certain pressurised tanks may not be filled greater than 98% full. So knowing how close to full a tank is, can be critical and the ullage reading is an important part of this process.

The word comes ultimately from the Latin oculus, “eye”, which was used in a figurative sense by the Romans for the bung hole of a barrel. This was taken into French in the medieval period as “oeil”, from which a verb “ouiller” was created, to fill a barrel up to the bung hole. In turn, a noun “ouillage” was created.

So ouillage was the immediate source of the word’s modern form, first recorded in Norman English about 1300, at first in the sense of the amount of liquid needed to fill a barrel up to the bung hole.

Umbilical Cables

Umbilical cables

Umbilical Cables – In most mammals, the umbilical cord is a conduit between the developing embryo or foetus and the placenta. It is the link which allows the host (mother) to maintain the developing baby. It is also the term used to describe cables which are used to control and sustain remote vehicles at sea and under the water.

An “umbilical cable” or umbilical is a cable and/or hose which supplies required consumables to an apparatus – whether a remote operated vehicle, an undersea plough or submersible. An umbilical can for example supply air and power to a pressure suit or hydraulic power, electrical power and fibre optics to subsea equipment. They are literally the lifeline to equipment which is away from the mother vessel.

Umbilicals are enclosed with an outer ring specially designed for the subsea environment to which it will be deployed. While they must withstand everyday wear and tear, as well as seabed temperatures.

The number of umbilicals used varies by development because each subsea project is unique – but each vehicle or system will likely have its own, and this will provide the dedicated services it needs to conduct operations. Additionally, umbilicals can be single or multiple connections in a single line.

There are several purposes for subsea umbilicals. Hydraulics are used to activate subsea wells, and some umbilicals pump chemicals into the production stream. Electrical umbilicals connect to subsea control panels and transmit information about temperature, pressure and subsea integrity, as well as electrical power to the subsea equipment. Fibre optic cables can instantly relay information to the surface about what’s happening below, and they can provide the means to transfer video feeds to the surface, so that engineers or ROV pilots can operate the equipment.

While the umbilical cables are vital for operations, they can also be a form of weakness. If the cable becomes tangled or trapped, it can become disconnected from the vehicle – and that can lead to the loss of valuable pieces of equipment. Usually the umbilical will be loosely wrapped around a sacrificial line which would take the strain and give an early indication of problems, potentially allowing time to pay out more umbilical as appropriate, or to try and recover.



Underway – Underway, or under way, is the term used to describe the state of a vessel in relation to its movement or otherwise in the water. “Way” arises when there is sufficient water flow past the rudder of a vessel that it can be steered. A vessel is said to be “underway” if it meets the following criteria:

• Not aground
• Not at anchor
• Not drifting
• Not made fast to a dock, the shore, or other stationary object.

The concept of whether a vessel is, or is not, “underway” has important legal ramifications – especially in the event of a collision. So, underway is used, when a vessel is not anchored or fixed to ground.

That does not necessarily mean that the vessel is “making way”, which refers to the vessel which is movement in water. Underway also refers to any time when the vessel is in water, no matter whether the vessel is in movement or stationary in water. So it is possible for a vessel to be underway, but not making way. There are many situations which can leave a vessel underway, but not making way.

The International Regulations for Preventing Collisions at Sea (COLREGS), Rule 23, have lighting criteria that must be exhibited. So a power-driven vessel underway shall exhibit:

• masthead light forward;
• second masthead light abaft of and higher than the forward one; except that a vessel of less than 50 metres in length shall not be obliged to exhibit such light but may do so;
• sidelights;
• sternlight.

“Under way” is likely from the Dutch “onderweg” or Middle Dutch “onderwegen” (literally meaning “under” or “among the ways”), while the German term for underway is “unterwegs”.

With an increasing number of vessels now using Dynamic Positioning, there are some who ponder the status of a vessel holding station. As you can see from the above description – a DP vessel would be underway, and under the same obligations and responsibilities as other vessels.



Underwriters – Marine insurance covers the loss or damage of ships, cargo, terminals, and any transport or cargo by which property is transferred, acquired, or held between the points of origin and final destination. It was the earliest well-developed kind of insurance, with origins in the Greek and Roman maritime law.

Separate marine insurance contracts were developed in Genoa and other Italian cities in the fourteenth century and spread to northern Europe. Premiums varied with intuitive estimates of the variable risk from seasons and pirates. These risks were “underwritten” in return for a premium being paid. The word “Underwriting” refers to protecting by way of insurance. Marine underwriting refers to providing marine insurance to the necessary clients.

Aside from the middle ages and the strangle hold of Lombardy merchants, the modern age saw Lloyd’s Coffee House become of the first marine insurance markets, as it was the meeting place for parties in the shipping industry wishing to insure cargoes and ships, and those willing to underwrite such ventures. These informal beginnings in the coffee shops of London, led to the establishment of the insurance market Lloyd’s of London and several related shipping and insurance businesses – including Lloyd’s List and Lloyd’s Register.

In 1906 the Marine Insurance Act codified the previous common law and in the 19th century, Lloyd’s and the Institute of London Underwriters (a grouping of London company insurers) developed between them standardised clauses for the use of marine insurance, and these have been maintained since.

The person or entity which provides marine underwriting is known as a marine underwriter. These are professionals whose main expertise is to ensure that their client is protected by unforeseen losses and casualties.

There are many different dimensions to proving marine insurance, and the underwriter is binding themselves in to covering some or all of any potential loss. There are differing types of cover, some relate to loss of the hull of the ship and the cargo it contained, others cover third party liabilities – which are covered by a Protection and Indemnity (P&I) policy.

Marine underwriting is a very tricky concept, it rests on analysing and assessing risk properly. In some ways it is a form of corporate gambling. Will the ship make it? How much of the risk am I willing to accept? These are the key questions for the underwriter.

Before a vessel can be insured, a marine underwriter must assess the probability of risk. Underwriters use a combination of statistics and investigation to determine the odds that a particular ship will be damaged or lost. A marine expert may inspect a cargo vessel, for instance, to check for proper seaworthiness and safety equipment. Underwriters also consider statistics such as the financial health of a shipping company and the history of past events and claims records.

Once a marine underwriter has estimated the potential risk to a ship, an insurance policy is created and the underwriter will sign under the policy, to show they have taken on the risk or elements of it.


Seafarer uniform

Uniform – Seafaring began as a commercial pursuit, and so merchant sailors far pre-dated the militaristic colleagues in the Navy. The title ‘Merchant Navy’ is relatively recent. It was granted by King George V after the First World War to recognise the contribution made by merchant sailors, as opposed to those on Royal Navy vessels.

While uniforms have been important for the military to denote rank and regiment, the commercial service had never really had much need for such differentiations. So the traditional uniform appeared surprisingly late.

Before the mid Seventeen hundreds, ships officers, and captains of commercial ships wore what they liked and whichever suited their trading routes. It has been recorded that one captain regularly took to wearing a plain black tailcoat and a white top hat.

According to historians, a sailors’ work clothes did not differ very greatly from those worn by peasants on land. Certainly there was nothing that could be described as any sort of general uniform which differentiated the sailor from the landsman, or even was common amongst all sailors. Historians claim that, “every man dressed as seemed good in his eyes” was the ruling.

The only concession was to the weather – and so sailors would wear a coat or “jerkin” in place of the doublets of the time, which were a form of waistcoat. From the 1750s onwards, there was a growth in global trade – and this meant more passengers being carried too. While traditionally commercial seafarers were never required to wear a uniform, they came into popular culture when the shipping companies which carried passengers started using systems of stripes and badges. These “uniforms” helped to identify crew from passengers, officers from seamen or ratings, as well as encouraging discipline, this was the birth of Merchant Navy uniforms in Britain and part of Europe. A trend which spread far and wide.

However, there was no official uniform of the Merchant Navy until one was introduced by the British Board of Trade in 1918. The uniforms then reflected not simply rank onboard, but of the responsibilities too. With gold bars and colours on epaulettes to denote who did what, and at what level.

Up until the late 1970s the trend had been for seafarers to usually wear uniform – but then as the 80s came around, as vessels flagged out from traditional closed registries – then the formality tended to fall away too.

Today most merchant seafarers are unlikely to wear a uniform – while cruise and passenger vessels have retained the uniform approach. The role of insignia, emblems, buttons and cap badges is returning back to whence it came, as a means of passengers knowing who is who, but not a primary concern on many vessel.

On most other types of commercial vessels, the focus is on operational matters…and so the boilersuit is the more usual uniform. While for ease many bridge watchkeepers and masters may make use of a simple white pilot shirt and black trousers, just to look smart but without having to pack too many clothes to take away.

As vessels tended to do away with strict communal areas, then the need for uniforms has fallen away too. Without a bar area, without a formal dinner service. Then there has not been much need for uniforms. It is perhaps understandable that the industry is moving more towards functional clothing over the elaborate hierarchical epaulettes and hats.

Unmanned Ship

Drone – unmanned ship

Unmanned Ships – There has been much talk in the shipping industry about unmanned ships. It seems the future will almost certainly see autonomous vessels plying their trade. While the use of “self-driving” cars has caught the public’s imagination, it is self-sailing ships which will impact the maritime industry.

Since 2014 Google’s driverless cars have been developing rapidly. Even on today’s roads the Tesla cars do have a form of “self-drive” capability – though since the first fatality these have been further refined and some aspects have literally gone back to the drawing board.

Away from the roads, it is to the air that most developments have been expended. The use of drone technology has become increasingly commonplace in the military, and while most drones are remotely piloted, there are moves to more autonomy and automation.

The drive for unmanned ships has come from a number of quarters – but the key advantages are efficiency, safety and costs savings over manned vessels.

The trend to reduce crews has been picking up pace from the 19th century. Ships which had hundreds of men were slashed with the advent of steam, which were further reduced with diesel propulsion. Today the crew numbers are usually in the mid to high teens.

The vision of an unmanned maritime future has been around since the 1970s, but it seems that finally the reality is within touching distance. While there have been many varied and imaginative schemes over the years it is the MUNIN (EU Project) that has kick started the current trend, and they have been researching and developing an unmanned bulk carrier simulation which used a combination of AI and tele-operation.

This lay the foundations for subsequent work by Rolls-Royce, and they firmly believe that unmanned cargo ships could become a reality within the decade. Rolls-Royce has stated that it is time to consider a road map to unmanned vessels of various types.

According to the company, the technology is in place, and they believe that some operations should be moved ashore. They believe there is a clear safety angle to this, and have questioned whether it is better to have a crew of 20 sailing in a gale in the North Sea, or say five in a control room on shore.

A remote-controlled ship would look quite different to a traditional one, largely because there would be no need for the facilities and systems currently needed for a crew. However, at the moment unmanned ships are currently illegal under international law. The International Chamber of Shipping has stated that it would require a complete overhaul of the regulatory regime.

There are currently two generic alternatives that are combined in an autonomous ship. There is the “remote ship” where the tasks of operating the ship are performed via a remote control mechanism e.g. by a shore based human operator and there is the “automated ship” where advanced decision support systems on board undertake all the operational decisions independently without intervention of a human operator.

The unmanned ships will rely on various sensor systems to detect problematic situations such as unexpected objects in the sea, dangerous weather conditions or danger of collision. If an unexpected situation occurs, an autonomous control module will be invoked trying to remedy the situation within its given constraints. If the system cannot achieve this, it will request support from a remote operator or start a fail-to-safe procedure if the operator is not available.

According to the MUNIN project, properly implemented, this type of autonomy will reduce the need for human supervision while maintaining a high and well defined level of safety. However, a major challenge will be to device sensor systems so that all relevant dangerous situations are reliably detected and appropriately acted upon.



Unseaworthy – Seaworthiness is a concept that runs through maritime law and requires that ships are constructed, outfitted, manned, and in all respects fitted for a voyage at sea. A shipowner has to provide the ship is good, and is in a condition to perform the voyage then about to be undertaken.

The issue of seaworthiness is fundamental to shipping, and in almost all shipping and carriage of goods by sea cases it is pivotal. It importance comes from the fact of its direct relation with both the commercial law and maritime law. The term is mainly used in the legal context and is often found in contracts entered into by the Company, e.g. charterparties and bills of lading.

Seaworthiness affects the liability of the carrier, the marine insurance, the environment and many issues related to carriage of goods by sea. The ISM Code and rules for the carriage of goods at sea, the Hague/Hague Visby Rules lay down standards and procedures for seaworthiness of the ship.

So the concept of being “seaworthy” means the ship is, fit to meet and undergo the perils of the sea and other incidental risks to which she must necessarily be exposed in the course of the voyage. If a vessel does not meet key criteria then it can be deemed unseaworthy, and that can lead to a host of problems.

The concept of “seaworthiness” covers: the ship, its equipment and supplies, the crew, the vessel’s suitability for the particular cargo and its suitability for the particular voyage or for particular ports. So the following examples would amount to unseaworthiness:

• An incompetent crew
• A crew which is insufficiently instructed or insufficient in numbers
• Out of date charts
• Insufficient bunkers for the voyage.
• Stowage which affects the safety of the ship.
• Deficient systems ashore or on board.
• The absence of documents required by law (including local law) for the satisfactory prosecution of the contemplated voyage e.g. a Safety Management System, an Ship Security Certificate, or
even something as simple as a deratting certificate.

The Hague/Hague-Visby Rules, state the obligation as to seaworthiness before and at the beginning of the voyage, so a seaworthy vessel before and at the commencement of each voyage. However, the Rotterdam Rules, which are intended to replace the current rules on the carriage of goods state the carrier will have to maintain seaworthiness throughout the voyage, not just at the start. The Rotterdam Rules are still considered to be years away from ratification, but the change if and when it comes could be hugely significant.

There is another parallel concept, that of “uncargoworthiness” – Cargoworthiness is categorised under the seaworthiness requirements, the vessel must be in every way reasonably fit to receive and carry the contemplated cargo in order to be considered as a seaworthy vessel. A ship can be considered uncargoworthy if there are conditions or other cargoes which may affect the potential cargo.