Seafaring “R” is for…
Let’s get this rolling with:
Radar – Radar is an “object-detection system” using radio waves to determine the range, angle, or velocity of objects. It can be used to detect any objects which reflect radio waves – so is particularly good at sea for identifying and monitoring other ships, land and even nearby weather.
Radar systems consist of a transmitter (Tx) producing electromagnetic waves in the radio or microwaves domain, an emitting antenna, a receiving (Rx) antenna (separate or the same as the previous one) to capture any returns from objects in the path of the emitted signal, a receiver and processor to determine properties of the object(s). They also have a screen which the operator can see the returns.
Radar was secretly developed by several nations in the period before and during World War II. The term “RADAR” was coined in 1940 by the United States Navy as an acronym for “RAdio Detection And Ranging”. The term radar has since entered English and other languages as a common noun.
The modern uses of radar are highly diverse – it is by no means just marine based. Uses include air and terrestrial traffic control, radar astronomy, air-defence systems, antimissile systems, aircraft anticollision systems, ocean surveillance systems, outer space surveillance and rendezvous systems, meteorological precipitation monitoring, altimetry and flight control systems, guided missile target locating systems, ground-penetrating radar for geological observations, and range-controlled radar for public health surveillance.
The information provided by radar includes the bearing and range (and therefore position) of the object from the radar scanner. It is thus used in many different fields where the need for such positioning is crucial. The first use of radar was for military purposes: to locate air, ground and sea targets. This evolved in the civilian field into applications for aircraft, ships, and roads.
The main use of a marine radar is to measure the bearing and distance of ships or objects, in order to prevent collisions, to navigate, and to fix their position at sea when within range of shore or other fixed references such as islands, buoys, and lightships. In port or in harbour, vessel traffic service (VTS) radar systems are used to monitor and regulate ship movements in busy waters.
Radars on a ship usually have an antenna on the top of the vessel – usually on the main mast – but sometimes further forward continuously rotates and sends out pulses of frequency beams that are transmitted from the radar. The frequency and the time taken by the pulses to return to the radar receiver, and details the objects it has bounced back from. These are displayed on a screen, which translates the data into a useable visual form, to enable navigators to see what is around the vessel.
Radio – Radio development began as “wireless telegraphy”, and while many other pioneers developed the systems, in 1894 the Italian inventor Guglielmo Marconi built the first complete, commercially successful wireless telegraphy system.
Marconi demonstrated application of radio in military and marine communications and started a company for the development and propagation of radio communication services and equipment.
By August 1895 Marconi was field testing his system but even with improvements he was only able to transmit signals up to one-half mile. Marconi’s experimental apparatus proved to be the first engineering-complete, commercially successful radio transmission system.
In 1896, Marconi was awarded a British patent and in 1897, he established a radio station on the Isle of Wight. Marconi opened his “wireless” factory in the former silk-works at Hall Street, Chelmsford, England in 1898, employing around 60 people.
Shortly after the 1900s, Marconi held the patent rights for radio. Marconi would go on to win the Nobel Prize in Physics in 1909 and be more successful than any other inventor in his ability to commercialise radio. Marconi’s apparatus is also credited for saving the 700 people that survived the tragic Titanic disaster.
Though it was not as safety which saw the earliest use of radio aboard ships. This was as an extra service to wealthy passengers who wanted to monitor their stock investments and run their businesses while at sea.
It was not until after the “Republic” and “Titanic” disasters that radio evolved from a luxury to a necessary safety device. Thought earlier in 1899 a freighter rammed the East Goodwin Lightship which was anchored ten miles offshore from Deal in the Straits of Dover off the south east coast of England. A distress call was transmitted by wireless to a shore station at South Foreland and help was dispatched.
It was soon clear how valuable wireless would be in saving lives at sea. But wireless had its limitations, notably in terms of the distance that could be covered.
Today radio communications sit within a more technical suite of options – as part of the Global Maritime Distress and Safety System (GMDSS), an international system which uses improved terrestrial and satellite technology and ship-board radio systems.
GMDSS is an integrated communications system which should ensure that no ship in distress can disappear without trace, and that more lives can be saved at sea. Under the GMDSS requirements, all ships are required to be equipped with satellite emergency position-indicating radiobeacons (EPIRBs) and NAVTEX receivers, to automatically receive shipping safety information.
The GMDSS communications system under SOLAS complements the International Convention on Maritime Search and Rescue (SAR), 1979, which was adopted to develop a Global SAR plan, so that no matter where an incident occurs, the rescue of persons in distress will be coordinated by a SAR organization and, where necessary, by co-ordination between neighbouring SAR countries.
Full implementation of the GMDSS was on 1 February 1999, almost exactly 100 years after the East Goodwin use of wireless technology to aid a ship in distress. With the completion of the SAR plans and the full implementation of the GMDSS, seafarers and ships’ passengers should feel safer and more secure at sea.
Reefer – A reefer ship is a refrigerated cargo ship; a type of ship typically used to transport perishable commodities which require temperature-controlled transportation, such as fruit, meat, fish, vegetables, dairy products and other foods.
By 1869, reefers were shipping beef carcasses frozen in a salt-ice mixture from Indianola, Texas, to New Orleans, Louisiana, to be served in hospitals, hotels and restaurants. By 1874 they were shipping frozen beef from America to London, which developed into an annual tonnage of around 10,000 short tons (8,900 long tons; 9,100 t).
The insulated cargo space was cooled by ice, which was loaded on departure. The success of this method was limited by insulation, loading techniques, ice block size, distance and climate.
The first attempt to ship refrigerated meat was made when the “Northam” sailed from Australia to the UK in 1876. The refrigeration machinery broke down en route and the cargo was lost. In 1877, the steamers “Le Frigorifique” and “Paraguay” carried frozen mutton from Argentina to France, proving the concept of refrigerated ships, if not the economics. In 1879 the “Strathleven”, equipped with compression refrigeration, sailed successfully from Sydney to the UK with 40 tons of frozen beef and mutton as a small part of her cargo.
Today entire ships dedicated to frozen goods are becoming rare – because it is better to retain flexibility, and the development of reefer containers has allowed this. Special refrigerated containers, commonly called reefers, can control temperatures, allowing everything from meat, fruit, vegetables and dairy products, to chemicals and pharmaceuticals to travel across the world.
Any particular goods can be kept at a controlled temperate. While some need cooling, others require special super-freeze reefers. These can keep goods frozen at temperatures as low as -60 degrees C. But other reefers can preserve goods at warmer temperatures if that is necessary.
It is not just temperature – de-humidification systems are able to ensure optimal humidity inside reefer containers. Some reefers also allow the atmosphere in the container to be controlled so for example, bananas can be shipped between continents without turning brown. Even fresh flowers can remain fresh in reefer containers while they are travelling many miles over several days. It is because of reefer containers, that grocery stores are able to stock and sell all kinds of fresh produce all year round.
Reefer containers generally come in 20 foot and 40 foot lengths, with the same general dimensions as that of dry cargo containers of the same size. However, there is slightly less cargo space available inside the reefer container due to the space taken up by the refrigeration unit and ventilation equipment.
Rigs – An oil rig is a large structure with facilities to drill wells (optionally), to extract and process oil and natural gas, or to temporarily store product until it can be brought to shore for refining and marketing. In many cases, the platform contains facilities to house the workforce as well.
Depending on the circumstances, the platform may be fixed to the ocean floor, may consist of an artificial island, or may float. Remote subsea wells may also be connected to a platform by flow lines and by umbilical connections. These sub-sea solutions may consist of one or more subsea wells, or of one or more manifold centres for multiple wells.
The development of offshore rigs gas has been based on exploiting oil and gas resources which lie underwater. Though, the origins were closer to shore – in lakes and rivers.
Around 1891, the first submerged oil wells were drilled from platforms built on piles in the fresh waters of the Grand Lake St. Marys in Ohio. The wells were developed by small local companies such as Bryson, Riley Oil, German-American, and Banker’s Oil.
Around 1896, the first submerged oil wells in salt water were drilled in the portion of the Summerland field extending under the Santa Barbara Channel in California. The wells were drilled from piers extending from land out into the channel.
In 1937, Pure Oil (now Chevron) and its partner Superior Oil (now ExxonMobil) used a fix platform to develop a field 1 mile offshore of Calcasieu Parish, Louisiana in 14 feet of water. In 1946, Magnolia Petroleum (now ExxonMobil) drilled at a site 18 miles off the coast, erecting a platform in 18 feet of water off St. Mary Parish, Louisiana.
When offshore drilling moved into deeper waters of up to 100 feet, fixed platform rigs were built, until demands for drilling equipment was needed in the 100- to 400-foot depth of the Gulf of Mexico, the first jack-up rigs began appearing from specialised offshore drilling contractors.
Notable offshore fields today are found in the North Sea, the Gulf of Mexico, the Campos and Santos Basins off the coasts of Brazil, Newfoundland and Nova Scotia, several fields off West Africa most notably west of Nigeria and Angola, as well as offshore fields in South East Asia and Sakhalin, Russia.
“Rigs” as they are considered come in different forms – there are Fixed Platforms, built on concrete or steel legs, or both, anchored directly onto the seabed. There are Semi-submersibles, which are platforms with hulls (columns and pontoons) of sufficient buoyancy to cause the structure to float, but of weight sufficient to keep the structure upright.
There are also Jack-up Mobile Drilling Units (or jack-ups), which are rigs that can be jacked up above the sea using legs that can be lowered, much like jacks. These MODUs (Mobile Offshore Drilling Units) are typically used in water depths up to 120 metres (390 ft), although some designs can go to 170 m (560 ft) depth.
Where rigs are not practical, as the moves out to deeper water take place – then they are being replaced by drillships. So the technology keeps adapting to the need to explore and exploit further offshore.
Rolling – The movement of a vessel in water is defined by the six degrees of freedom that a ship, boat or any other craft can experience. These are rolling, surging, pitching, swaying, yawing and heaving.
Rolling of a Ship is the rocking motion of a floating vessel caused by waves or other external forces. This form of rolling is characterised by amplitude, period (frequency), and phase shift of the oscillations relative to the external force.
Rolling causes a reduction in the velocity of the ship, negatively affects the crew with seasickness, and adversely affects the working of machinery and instruments. Ships are of course designed to tolerate a degree of rolling, and equipment and cargo stowed with this in mind, but if the rolling is extended or extreme, then this can be extremely damaging.
During intense rolling, the ship may capsize because of external loads not dangerous in the absence of rolling. Moderation in rolling is one of the most important features of the seaworthiness of a ship. The longer the period and the smaller the amplitude of rolling, the better the seaworthiness. Ship stabilizers are installed to control rolling.
Rolling can force a vessel to react even further than the original wave forced motion – with shifting of cargo or even leaking of ballast. A list normally refers to an unintentional or unexpected offset, as caused by flooding, battle damage, shifting cargo, etc. The rolling motion towards a steady state (or list) angle due to the ship’s own weight distribution is referred in marine engineering as heel.
Rolling can be more than just uncomfortable, it can be deadly and cause sinking, this is when a simple rolling action evolves into something more serious – either “synchronous rolling” or “parametric Rolling”.
Synchronous Rolling takes place because of resonance between, the natural period of roll of the ship and the natural period of the oscillation of the waves. The rolling will gradually increase to high capsizing values.
It is important that synchronous rolling is dealt with, and if it is encountered the vessel should immediately alter course to attack the sea at a different angle. If synchronism was occurring in on the original course it will not occur at new course, as the pattern of movement will have been changed and the resonance removed.
Parametric rolling can occur during rough seas while moderately pitching the vessel rolls to one side simultaneously because it is thrown up and down on water. The bow is down inside water and ship has rolled to one side the sudden immersion of large flare (this specially takes place in container vessels since they have very large flares) causes the restoring buoyancy force to push the bow upwards and to roll to other side.
The opposite happens to the other side and within a few cycles of such rolling the angle of roll will reach the large angles. The maximum angle of roll would occur at the maximum dip of the bow during pitching. Such parametric rolling is a phenomenon where by a ship which is pitching moderately in bad weather suddenly experiences very heavy rolling without warning.
If a vessel begins to experience parametric rolling, it is vital that the conditions which are causing it are changed. The weather is likely to be stuck for a while, so the vessel must take action. Changing the heading and bringing the wind broad on the bow can help, as can steering a zig-zag course until the weather abates and the conditions ease.
Ro-Ro – Roll-on/roll-off (RORO or ro-ro) ships are vessels designed to carry wheeled cargo. RORO cargo consists of items such as tractors, buses and trucks, or oversized cargo loaded on special flatbed or trailers.
The RoRo key is exactly that, the Roll-on/roll-off element, as the wheeled cargo is driven on and off the ship on their own wheels or using a platform vehicle, such as a self-propelled modular transporter. This is in contrast to lift-on/lift-off (LoLo) vessels, which use a crane to load and unload cargo.
RORO vessels have either built-in or shore-based ramps that allow the cargo to be efficiently rolled on and 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 large oceangoing vessels. The ramps and doors may be located in stern, bow or sides, or any combination thereof.
At first, wheeled vehicles carried as cargo on oceangoing ships were treated like any other cargo. Automobiles had their fuel tanks emptied and their batteries disconnected before being hoisted into the ship’s hold, where they were chocked and secured. This process was tedious and difficult, and vehicles were subject to damage and could not be used for routine travel.
The first roll-on/roll-off vessel that was purpose-built to transport loaded semi trucks was “Searoad of Hyannis”, which began operation in 1956. The ship had a very small capacity, indeed it could transport just three semi trailers, but it was a capability that began to be scaled up very quickly.
In 1957, the US military issued a contract to the Sun Shipbuilding and Dry Dock Company in Chester, Pennsylvania, for the construction of a new type of motorized vehicle carrier. The ship, the “Comet”, had a stern ramp as well as interior ramps, which allowed cars to drive directly from the dock, onto the ship, and into place.
This ramp system meant both loading and unloading were sped up dramatically.
The RoRo passenger ferry with the greatest car-carrying capacity is the Irish Ferries “Ulysses”. The giant operates between Dublin and Holyhead. It can carry 1342 cars and 4101 lane meters of cargo, and is 209.02 m long and 31.84 m wide.
While ferries have taken to the RoRo concept, the real sector which takes advantage is the automotive industry. The first cargo ships specially fitted for the transport of large quantities of cars came into service in the early sixties.
These ships still had their own loading gear and so-called hanging decks inside. They were, for example, chartered by the German Volkswagen AG to transport vehicles in the U.S. and Canada. Since 1970, the market for exporting and importing cars has increased dramatically and the number and type of ROROs has increased also.
In 1973, Japan’s K Line built European Highway, the first pure car carrier (PCC), which carried 4,200 automobiles. Today’s pure car carriers and their close cousins, the pure car/truck carrier (PCTC), are distinctive ships with a box-like superstructure running the entire length and breadth of the hull, fully enclosing the cargo.
With the building of Wallenius Wilhelmsen Logistics’ 8,000-CEU car carrier Faust out of Stockholm in June 2007 car carriers entered a new era of the large car and truck carrier (LCTC). Currently, the largest are Wilh. Wilhelmsen’s “Mark V” ships, led by “MV Tønsberg”. The car carrier “Auriga Leader”, built in 2008 with a capacity of 6,200 cars, is the world’s first partially solar powered ship.
RoRo vessels have come with safety concerns over the years. From the likes of Townsend Thoreson’s tragic “Herald of Free Enterprise” – lost owing to bow doors being left open, through to other losses. They are complex vessels, and the use of such wide open spaces in vessels can bring stability issues which have to be addressed.
Route Planning – We have covered “passage planning” in the letter P – being the procedure to develop a complete detailed strategy of a vessel’s voyage from start to finish, or “berth to berth”.
Having and using a passage plan is essential, and it is important to gather and consider more than just the future events including landfalls, narrow passages, and course changes expected during the voyage. There are other conditions which have to be accounted for.
Perhaps the most obvious routing issue is in order to combat the potential impact of adverse weather – and so route planning makes up an important management and planning tool for open-ocean passages.
Most planning systems or software allow for the navigation officer and master to develop a route which optimises the route, and which minimises the risk of damage to vessel and cargo. Another key issue is to maximise fuel efficiency within the constraints of the desired arrival time.
Route planning tools allow access to detailed weather forecasts along pre-defined routes, plus route optimisation based on weather avoidance, arrival time or fuel efficiency. The route forecasts usually provide for and report on:
• Wind speed and direction
• Significant and maximum wave height
• Peak period and wave direction
• Storm risks
• Hurricane or Typhoon warnings
It is also useful to allow for prevailing positive conditions – and so some route planning tools will make sure that a route takes into account the current directions and wind, so as to provide positives for the vessel, as opposed to making their clients batter their way through tough conditions and sea states.
Routing does not just have to take into account weather. There are other potential problems which vessels need to consider. An important one is security. The threat of piracy, terrorism or other forms of crime are real and serious issues.
Planning to avoid areas of heightened activity was particularly important during the recent piracy epidemic in the Indian Ocean, off Somalia and in the Gulf of Aden and Red Sea.