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DIFFERENT TYPES OF SHIPS

1.ROLL – ON/ROLL – OFF SHIPS

Roll-on/roll-off (RORO) ships are vessels designed to carry wheeled cargo such as automobiles, trucks,

semi-trailer trucks, trailers or 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.

Various types of RORO vessels include ferries, cruise ferries, cargo ships, and barges. New automobiles that are

transported by ship are often moved on a large type of RORO called a Pure Car Carrier (PCC) or Pure Car Truck

Carrier (PCTC).

Seaworthiness of RORO vessels

The seagoing RORO car ferry, with large external doors close to the waterline and open vehicle decks with

few internal bulkheads has a reputation for being a high risk design. An improperly-secured loading door

can cause a ship to take on water and sink, as happened for example in 1987 with the MS Herald of Free

Enterprise. Water sloshing on the vehicle deck can set up a free surface effect making the ship unstable and

causing it to capsize.

A Roll-On/Roll-Off [RO/RO] ship is specifically designed to carry wheeled and tracked vehicles as all or most of its cargo. Vehicles are driven or towed on and off the ship by means of either the ship's own ramps or shore-based ramps. Because it is designed to accommodate cargoes which cannot be stacked but which vary in height, below-deck space and volume utilization is generally less efficient than on a containership. RO/RO ships are thus commercially viable only in certain specialized trades. However, the RO/RO is the preferred ship type for deployment of military unit equipment.

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2. BULK CARRIER

A bulk carrier, bulk freighter, or bulker is a merchant ship specially designed to transport unpackaged

bulk cargo, such as grains, coal, ore, and cement in its cargo holds. Since the first specialized bulk carrier

was built in 1852, economic forces have fuelled the development of these ships, causing them to grow in

size and sophistication. Today's bulkers are specially designed to maximize capacity, safety, efficiency, and

to be able to withstand the rigors of their work.

Today, bulkers make up 40% of the world's merchant fleets and range in size from single-hold mini-bulkers

to mammoth ore ships able to carry 400,000 metric tons of deadweight (DWT). A number of specialized

designs exist: some can unload their own cargo, some depend on port facilities for unloading, and some even

package the cargo as it is loaded. Over half of all bulkers have Greek, Japanese, or Chinese owners and more

than a quarter are registered in Panama. Korea is the largest single builder of bulkers, and 82% of these ships

were built in Asia.

A bulk carrier's crew participates in the loading and unloading of cargo, navigating the ship, and keeping its

machinery and equipment properly maintained. Loading and unloading the cargo is difficult, dangerous, and

can take up to 120 hours on larger ships. Crews can range in size from three people on the smallest ships to

over 30 on the largest.

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 bulker sinkings in the 1990s, as have the bulker's large

hatchways, important for efficient cargo handling. New international regulations have since been introduced

to improve ship design and inspection, and to streamline the process of abandoning ship.

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Definition

There are various ways to define the term bulk carrier. The International Convention for the Safety of Life

at Sea defines a bulk carrier as "a ship constructed with a single deck, top side tanks and hopper side tanks in

cargo spaces and intended to primarily carry dry cargo in bulk; an ore carrier; or a combination carrier."

However, most classification societies use a broader definition where a bulker is any ship that carries dry

unpackaged goods. Multipurpose cargo ships can carry bulk cargo, but can also carry other cargoes and are

not specifically designed for bulk carriage. The term "dry bulk carrier" is used to distinguish bulkers from

bulk liquid carriers such as oil, chemical, or liquefied petroleum gas carriers. Very small bulkers are almost

indistinguishable from general cargo ships, and they are often classified based more on the ship's use than its

design.

A number of abbreviations are used to describe bulkers. "OBO" describes a bulker which carries a

combination of ore, bulk, and oil, and "O/O" is used for combination oil and ore carriers. The terms

"VLOC," "VLBC," "ULOC," and "ULBC" for very large and ultra large ore and bulk carriers were adapted

from the supertanker designations very large crude carrier and ultra large crude carrier.

Cross section of a typical bulker

1. Cargo hold

2. Hatch cover

3. Upper hopper tank for water ballast or oil

4. Double bottom

5. Lower hopper tank, for water ballast

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DESCRIPTIONS OF GENERAL TYPES OF BULK CARRIERS

Geared bulk carriers are typically in the handysize to handymax size range although there are a small number

of geared panamax vessels, like all bulkers they feature a series of holds covered by prominent hatch covers.

They have cranes, derricks or conveyors that allow them to load or discharge cargo in ports without shore-

based equipment. This gives geared bulkers flexibility in the cargoes they can carry and the routes they can

travel. (Photo: A typical geared handysize bulk carrier.)

Combined carriers are designed to transport both liquid and dry bulk cargoes. If both are carried

simultaneously, they are segregated in separate holds and tanks. Combined carriers require special design and

are expensive. They were prevalent in the 1970s, but their numbers have dwindled since 1990. (Photo: The oil

pipeline and dry bulk hold aboard the Maya.)

Gearless carriers are bulkers without cranes or conveyors. These ships depend on shore-based equipment at

their ports of call for loading and discharging. They range across all sizes, the larger bulk carriers (VLOCs) can

only dock at the largest ports, some of these are designed with a single port-to-port trade in mind. The use of

gearless bulkers avoids the costs of installing, operating, and maintaining cranes. (Photo:Berge Athen, a

225,000 ton gearless bulker.)

Selfdischargers are bulkers with conveyor belts, or with the use of an excavator that is fitted on a traverse

running over the vessel's entire hatch, and that is able to move sideways as well. This allows them to discharge

their cargo quickly and efficiently. (Photo: The John B. Aird a self-discharging lake freighter.)

Lakers are the bulkers prominent on the Great Lakes, often identifiable by having a forward house which helps

in transiting locks. Operating in fresh water, these ships suffer much less corrosion damage and have a much

longer lifespan than saltwater ships. As of 2005, there were 98 lakers of 10,000 DWT or over. (Photo: Edmund

Fitzgerald, a Great Lakes bulker.)

BIBO or "Bulk In, Bags Out" bulkers are equipped to bag cargo as it is unloaded. The CHL Innovator, shown in

the photo, is a BIBO bulker. In one hour, this ship can unload 300 tons of bulk sugar and package it into 50 kg

sacks.

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3. PASSENGER SHIPS

A passenger ship is a ship whose primary function is to carry passengers. The category does not include cargo vessels

which have accommodations for limited numbers of passengers, such as the ubiquitous twelve-passenger freighters

once common on the seas in which the transport of passengers is secondary to the carriage of freight. The type does

however include many classes of ships designed to transport substantial numbers of passengers as well as freight.

Indeed, until recently virtually all ocean liners were able to transport mail, package freight and express, and other

cargo in addition to passenger luggage, and were equipped with cargo holds and derricks, kingposts, or other cargo-

handling gear for that purpose. Only in more recent ocean liners and in virtually all cruise ships has this cargo capacity

been eliminated.

While typically passenger ships are part of the merchant marine, passenger ships have also been used as

troopships and often are commissioned as naval ships when used as for that purpose.

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4. DREDGERS

Dredging is an excavation activity or operation usually carried out at least partly underwater, in shallow

seas or fresh water areas with the purpose of gathering up bottom sediments and disposing of them at a

different location. This technique is often used to keep waterways navigable.

It is also used as a way to replenish sand on some public beaches, where too much sand has been lost

because of coastal erosion. Dredging is also used as a technique for fishing for certain species of edible

clams and crabs, see fishing dredge.

A dredger is a device for scraping or sucking the seabed, used for dredging. It is a ship or boat equipped

with a dredge. The terms are sometimes interchanged.

The process of dredging creates spoils (excess material), which are carried away from the dredged area.

Dredging can produce materials for land reclamation or other purposes (usually construction-related), and

has also historically played a significant role in gold mining. Dredging can create disturbance in aquatic

ecosystems, often with adverse impacts.

Types of dredging vessels

Suction

For suction-type excavation out of water, see Suction excavator.

These operate by sucking through a long tube, like some vacuum cleaners but on a big scale.

A plain suction dredger has no tool at the end of the suction pipe to disturb the material. This is often the

most commonly used form of dredging.

Trailing suction

A trailing suction hopper dredger (TSHD) trails its suction pipe when working, and loads the dredge spoil

into one or more hoppers in the vessel. When the hoppers are full, the TSHD sails to a disposal area and

either dumps the material through doors in the hull or pumps the material out of the hoppers. Some dredges

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also self-offload using drag buckets and conveyors. The largest trailing suction hopper dredger in the world

is currently Jan De Nul's Cristobal Colon.

Cutter suction

A cutter-suction dredger's (CSD) suction tube has a cutter head at the suction inlet, to loosen the earth and

transport it to the suction mouth. The cutter can also be used for hard surface materials like gravel or rock.

The dredged soil is usually sucked up by a wear-resistant centrifugal pump and discharged through a pipe

line or to a barge. In recent years, dredgers with more powerful cutters have been built in order to excavate

harder rock without blasting.

Auger suction

This process functions like a cutter suction dredger, but the cutting tool is a rotating Archimedean screw set

at right angles to the suction pipe. The first widely used auger dredges were designed by Mud Cat Dredges

in the 1980s which was run by National Car Rental, but is now a Division of Ellicott Dredges. In 1996, IMS

Dredges introduced a self-propelled version of the auger dredge that allows the system to propel itself

without the use of anchors cables. During the 1980s and 1990s auger dredges were primarily used for sludge

removal applications from waste water treatment plants. Today, auger dredges are used for a wider variety

of applications including river maintenance and sand mining. The most common auger dredge on the global

market today is the Versi-Dredge. The turbidity shroud on auger dredge systems creates a strong suction

vacuum and creates much less turbity than conical (basket) type cutterheads and that is why they are

preferred for environmental type applications. The vacuum created by the shroud and the ability to convey

material to the pump faster makes auger dredge systems more productive than similar sized conical (basket)

type cutterhead dredges.

Jet-lift

These use the Venturi effect of a concentrated high-speed stream of water to pull the nearby water, together

with bed material, into a pipe.

Air-lift

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An airlift is a type of small suction dredge. It is sometimes used like other dredges. At other times, an airlift

is used, handheld underwater by a diver. It works by blowing air into the pipe, and that air, being lighter than

water, rises inside the pipe, dragging water with it.

Bucket

A bucket dredger is equipped with a bucket dredge, which is a device that picks up sediment by mechanical means,

often with many circulating buckets attached to a wheel or chain. Some bucket dredgers and grab dredgers are

powerful enough to rip out coral to make a shipping channel through coral reefs.

Grab

Grab dredger picks up seabed material with a clam shell grab, which hangs from an onboard crane or a crane

ship, or is carried by a hydraulic arm, or is mounted like on a dragline. This technique is often used in

excavation of bay mud. Most of these dredges are crane barges with spuds.

Backhoe/dipper

A backhoe/dipper dredge has a backhoe like on some excavators. A crude but usable backhoe dredger can be

made by mounting a land-type backhoe excavator on a pontoon. The six largest backhoe dredgers in the

world are currently the Vitruvius, the Mimar Sinan, Postnik Jakovlev (Jan De Nul), the Samson (DEME),

the Simson and the Goliath (Van Oord). They featured barge-mounted excavators. Small backhoe dredgers

can be track-mounted and work from the bank of ditches. A backhoe dredger is equipped with a half-open

shell. The shell is filled moving towards the machine. Usually dredges material is loaded in barges. This

machine is mainly used in harbors and other shallow water.

Water injection

A water injection dredger uses a small jet to inject water under low pressure (to prevent the sediment from

exploding into the surrounding waters) into the seabed to bring the sediment in suspension, which then

becomes a turbidity current, which flows away down slope, is moved by a second burst of water from the

WID or is carried away in natural currents. Water injection results in a lot of sediment in the water which

makes measurement with most hydrographic equipment (for instance: singlebeam echosounders) difficult.

Pneumatic

These dredgers use a chamber with inlets, out of which the water is pumped with the inlets closed. It is

usually suspended from a crane on land or from a small pontoon or barge. Its effectiveness depends on depth

pressure.

Bed leveller

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This is a bar or blade which is pulled over the seabed behind any suitable ship or boat. It has an effect

similar to that of a bulldozer on land. The chain-operated steam dredger Bertha, built in 1844 to a design by

Brunel and now the oldest operational steam vessel in Britain, was of this type.

Krabbelaar

This is an early type of dredger which was formerly used in shallow water in the Netherlands. It was a flat-

bottomed boat with spikes sticking out of its bottom. As tide current pulled the boat, the spikes scraped

seabed material loose, and the tide current washed the material away, hopefully to deeper water. Krabbelaar

is Dutch for "scratcher".

Snagboat

A snagboat is designed to remove big debris such as dead trees and parts of trees from rivers and canals.

Amphibious

Some of these are any of the above types of dredger, which can operate normally, or by extending legs, also

known as spuds, so it stands on the seabed with its hull out of the water. Some forms can go on land.

Some of these are land-type backhoe excavators whose wheels are on long hinged legs so it can drive into

shallow water and keep its cab out of water. Some of these may not have a floatable hull and, if so, cannot

work in deep water.

Submersible

These are usually used to recover useful materials from the seabed. Many of them travel on caterpillar

tracks. A unique variant is intended to walk on legs on the seabed. Fishing dredges are used to collect

various species of clams scallops, oysters or crabs from the seabed. These dredges have the form of a scoop

made of chain mesh, and are towed by a fishing boat. Careless dredging can be destructive to the seabed.

Nowadays some scallop dredging is replaced by collecting via scuba diving.

Police drag

In some police departments a small dredge (sometimes called a drag) is used to find and recover objects and

bodies from underwater. The bodies may be murder victims, or people who committed suicide by drowning,

or victims of accidents. It is sometimes pulled by men walking on the bank.

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5. CHEMICAL TANKER

A chemical tanker is a type of tanker designed to transport chemicals in bulk.

Ocean-going chemical tankers generally range from 5,000 metric tons deadweight (DWT) to 40,000 DWT

in size, which is considerably smaller than the average size of other tanker types due to the specialised

nature of their cargoes and the size restrictions of the port terminals where they call to load and discharge.

Chemical tankers normally have a series of separate cargo tanks which are either coated with specialised

coatings such as phenolic epoxy or zinc paint, or made from stainless steel. The coating or cargo tank

material determines what types of cargo a particular tank can carry: stainless steel tanks are required for

aggressive acid cargoes such as sulphuric and phosphoric acid Chemical tankers often have a system for

tank heating in order to maintain the viscosity of certain cargoes - typically this system consists of a boiler

which pumps pressurized steam through so-called 'heating coils' - stainless steel pipes - in the cargo tanks,

thus transferring heat into the cargo which circulates in the tank by convection. Many modern chemical

tankers feature double hull construction and have one tank for each pump with separate piping, which means

that each tank can load a separate cargo without any mixing. Tank cleaning after discharging cargo is a very

important aspect of chemical tanker operations, because tanks which are not properly cleaned of all cargo

residue can adversely affect the purity of the next cargo loaded. Before tanks are cleaned, it is very

important that they are properly ventilated and checked to be free of potentially explosive gases.

Most new chemical tankers are built by shipbuilders in Japan, Korea or China, with other builders in Turkey,

Italy, Germany and Poland.

While 'easier' cargoes - e.g. vegetable oil - can be carried in epoxy coated tanks.

(1 )A Chemical Tanker

(2) The deck of a chemical tanker has a complicated piping system. This is the Saudi chemical tanker of

43,851 metric tons deadweight (DWT) 1986 Built Al Farabi, carrying molasses, in Brest.

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6. CARGO SHIPS A cargo ship or freighter is any sort of ship or vessel that carries cargo, goods, and materials from one port to

another. Thousands of cargo carriers ply the world's seas and oceans each year; they handle the bulk of international

trade. Cargo ships are usually specially designed for the task, often being equipped with cranes and other

mechanisms to load and unload, and come in all sizes. Today, they are almost always built of welded steel, and with

some exceptions generally have a life expectancy of 25 to 30 years before being scrapped.

Cargo ships/freighters can be divided into four groups, according to the type of cargo they carry. These

groups are:

1. General Cargo Vessels

2. Tankers

3. Dry-bulk Carriers

4. Multipurpose Vessels

General Cargo Vessels carry packaged items like chemicals, foods, furniture, machinery, motor vehicles,

footwear, garments, etc.

Tankers carry petroleum products or other liquid cargo.

Dry Bulk Carriers carry coal, grain, ore and other similar products in loose form.

Multi-purpose Vessels, as the name suggests, carry different classes of cargo – e.g. liquid and general cargo

– at the same time.

Specialized types of cargo vessels include container ships and bulk carriers (technically tankers of all sizes

are cargo ships, although they are routinely thought of as a separate category). Cargo ships fall into two

further categories that reflect the services they offer to industry: liner and tramp services. Those on a fixed

published schedule and fixed tariff rates are cargo liners. Tramp ships do not have fixed schedules. Users

charter them to haul loads. Generally, the smaller shipping companies and private individuals operate tramp

ships. Cargo liners run on fixed schedules published by the shipping companies. Each trip a liner takes is

called a voyage. Liners mostly carry general cargo. However, some cargo liners may carry passengers also.

A cargo liner that carries 12 or more passengers is called a combination or passenger-cum-cargo line.

http://en.wikipedia.org/wiki/Cargo_ship

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7. CONTAINER SHIPS The hull, similar to bulk carriers and general cargo ships, is built around a strong keel. Into this frame is set

one or more below-deck cargo holds, numerous tanks, and the engine room. The holds are topped by hatch

covers, onto which more containers can be stacked. Many container ships have cargo cranes installed on

them, and some have specialized systems for securing containers on board.

The hull of a modern cargo ship is a complex arrangement of steel plates and strengthening beams. The hull

is built around the keel. Resembling ribs, and fastened at right-angles to the keel are the ship's frames.The

ship's main deck, the metal platework that covers the top of the hull framework, is supported by beams that

are attached to the tops of the frames and run the full breadth of the ship.The beams not only support the

deck, but along with the deck, frames, and transverse bulkheads, strengthen and reinforce the shell. Another

feature of recent hulls is a set of double-bottom tanks, which provide a second watertight shell that runs

most of the length of a ship. The double-bottoms generally hold liquids such as fuel oil, ballast water or

fresh water.

A ship's engine room houses its main engines and auxiliary machinery such as the fresh water and sewage

systems, electrical generators, fire pumps, and air conditioners. In most new ships, the engine room is

located in the after portion of the ship.

A major characteristic of a container ship is whether it has cranes installed for handling its cargo. Those that

have cargo cranes are called geared and those that don't are called ungeared or gearless. The earliest

purpose-built container ships in the 1970s were all gearless. Since then, the percentage of geared newbuilds

has fluctuated widely, but has been decreasing overall, with only 7.5% of the container ship capacity in 2009

being equipped with cranes.

While geared container ships are more flexible in that they can visit ports that are not equipped with pierside

cranes, they suffer from several drawbacks. To begin with, geared ships will cost more to purchase than a

gearless ship. Geared ships also incur greater recurring expenses, such as maintenance and fuel costs.

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8. OBO CARRIERS

OBO is an abbreviated name for Oil- Bulk- Ore cargo vessel. These are specially designed vessels which

carry cargo in bulk in both liquid and dry form. The OBO vessels are some of the most highly sophisticated

cargo vessels sailing today.

OBO Carrier OBO vessel are expensive to build but because of their capability of carrying wet and dry cargo together

,they provide a more economical option as this feature reduces the number of empty voyages or ballast

voyages.

A bulk carrier can carry only dry cargo and a tanker can carry only liquid cargo. These make these two types

of vessels to ply only on fix voyages with least flexibility. On the other hand, OBO vessels have

multipurpose capability which allows them to ply on different voyages as per the demand and supply of the

market to make the maximum profit.

OBO vessels were very popular in the year 1955-1980 and a sudden rise was seen during this period. One of

the biggest OBO carriers of this period –MV Derbyshire was of approximately 180000 DWT.

Unfortunately, it sank in the Pacific Ocean after fighting a terrific storm while it was carrying ore as cargo.

OBO– Construction and Features OBO is normally constructed with a single deck to impart structural strength to the vessel in addition to

several divisions of transverse bulkheads which divides the cargo holds.

Hatches for cargo hold are generally made in two pieces as larger and single hatches will reduce the

structural strength of the ship. Also unlike bulk carriers, OBO vessel has pipe lines and equipment’s on deck

which are used in operation while carrying liquid cargo. Moreover, a single large cover can hinder the

operation of loading and unloading of oil cargo.

However, OBO vessels are losing their popularity because of the following reasons:

1) They are expensive to construct.

2) Loading of bulk cargo requires conveyors and grabs. Due to small hatch opening, the access for bigger

grab and belts become difficult and take more time to load / unload the cargo.

3) Additional trimming of ship is required as the equipment above the deck can hinder the crane movement.

4) Equipments located above the hatches have to be removed temporarily by means of crane, which

increases the port stay and overall cost of operation.

5) The equipments above deck can be damaged by the cranes and equipment used for loading and unloading

operation of bulk cargo.

6) The load distribution of OBO ship is not even and the overall structure is not stiff which may result in

deformation of bulkhead at rough weather.

7) Another major problem of OBO ship is the movement of cargo in the hold which results in list and

instability of the ship due to the shift in the center of gravity of the ship.

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9. Barge Carrier Ships

The loading and discharging of floating containers or vessels with such ships is as a rule done on free water

by shipborne lifting devices which pick up the floating vessels from the water for transfer to the ship and

vice versa. Such expensive shipborne lifting devices have the common disadvantage that they require an

assembly of a large number of individual parts with a relatively low degree of reliability and in most cases

the loading and unloading operations are impaired by the sea water conditions and the atmospheric

environment of the ship. A further disadvantage is that such vessels usually have to be operated by shore

side personnel because of the prevailing agreements between ship owners and longshoremen unions. Such

personnel are normally unable to operate such gear as carefully and safely as a trained crew of the ship. In

addition with the use of travelling ship cranes for the handling of floating vessels, the cranes sensitivity to

the ship's inclination is a further disadvantage.

Barge ships are designed to carry specially designed barges (lighters) or a combination of such barges and

containers. Thus, they are necessarily large ships with a large heavy lift capability. Their design was

intended to combine the flexibility and self-sustained cargo handling capability of the general cargo ship

with the rapid port turnaround time of the RO/RO and containership. This combination, however, has not

proved commercially viable in most trades.

The search for more economic modes of cargo transportation has led to the introduction of designs of sea-

going transport ships with facility for taking a number of loaded barges on board. Such systems of

transportation afford a number of advantages, notably in simplifying the transfer of cargo from inland sites

to an ocean transport ship via inland waterways and the eventual transport of the cargo to coastal or inland

delivery points. By eliminating the off-loading of cargo from the barges into the transport ship and vice

versa, important labour and energy cost savings are achieved and the speed and general convenience of the

water-borne transportation exercise is enhanced.

In the transport of cargo throughout the world, cargo must often be transported in various types of vessels

depending on the depth of the water in which the vessel travels. For example, when grain from the Midwest

is harvested for transport to foreign countries, the grain must be placed in relatively shallow vessels such as

barges or the like and moved down river, such as the Mississippi River, to grain elevators where the grain is

then unloaded from the barges, into the grain elevators. Subsequently a deep draft vessel, such as a cargo

ship, is then loaded with the grain so that the ship may then transport the grain cargo to foreign ports. Most

grain elevators would be located for example, between New Orleans and Baton Rouge, since any travel

north of Baton Rouge by a deep draft vessel is impossible because of the shallow depth of the Mississippi

River. Even on the occasion where the deep draft vessel can receive the cargo of grain directly from the

shallow draft barge, again time and effort and expenses are incurred when this transfer is undertaken.

Barge Carrier Variants

SEABARGE (SEABEE)

The SEABARGE (SEABEE) is arranged much differently from the LASH in that it has three decks on

which the cargo barges or container flats are stowed. Barges are brought to each deck level by a stern

elevator and are moved internally within the ship by the Transporter (conveyor) System. Two barges can be

loaded or discharged in a cycle of about 40 minutes. SEABEE barge ships can carry up to 38 sea barges

(97'6" long x 35' wide x 16'11" high). The elevator capacity is 2,000 LT. The SEABEE ship is the preferred

ship to transport landing craft, utility, and lighter, amphibious resupply, cargo 60 ton. The military

advantages of barge carriers include their suitability to carry either unit equipment, sustaining supplies, or

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ammunition; the ability to carry amphibious lighter age and the capability to preload the barges before ship

arrival and to discharge cargo from the barges at relatively austere port facilities, after the ship has sailed.

Their military disadvantages include a complete dependence on a single, very complicated mechanical

system for barge discharge; the barge's dependence, once afloat, upon the availability of towage and the

overall unsuitability of the barges for towing outside harbors or other protected waters.

BACO (Barge / Container)

BACO liners (barge/container liners) operate in accordance with the dock principle. In this German-

developed system, the barges are floated through bow doors into the carrier, which has been lowered by

taking on ballast. The special feature of these maneuvers is that fact that these barges float in the ship's

storage area and the ship must open its bow in order for them to float in and out. Empty barges have an

empty height of approx. 7 m. The skipper can look straight out over the barges when pushing, which

requires sure instinct and driving expertise on the part of the crew for this maneuver. Once the bow doors

have been closed, the water is pumped out of the dock and the barges are secured with special fittings. The

special BACO barges measure 24 m x 9.50 m and, at a deadweight of 800 metric tons, have a draft of 4.10

m. However, the particular dimensions of the carrier ships are such that other types of barge and even inland

waterway vessels and lighters can also be carried. Several tiers of containers can be carried on deck and be

loaded and unloaded with on-board lifting gear. The Seereederei Baco-Liner GmbH, based in Duisburg, we

run a regular conventional and Container liner service between North-West-European and West-African

ports and vice versa. BACO Liner with their unique Barge / Container carrying vessels are considered the

No 1 service to West Africa. This system allows the vessels to arrive and discharge midstream in African

Ports, thus avoiding port delays.

CONDOCK

CONDOCK - the synonym for CON tainer-, DOCK-, and Ro/Ro-vessel features the combined versatility for

the marine-transportation of Container, large and heavy loads in the Ro/Ro mode and the wide range of

General cargoes. The special design of these vessels is their capability of the safe loading and transportation

of floating units by semi-submersible dock-operation or utilization as a mobile Dry Dock. The vessels may

trade worldwide with open or removed hatchcovers, resulting in nearly unlimited cargo heights.

Cargo transport ships utilising a so-called float-on cargo-loading principle have been built. In 1978 the

CONDOCK-Type vessel was designed in close co-operation with a German Shipyard. The Condock I of

3,603 dwat featured 2 cranes on the starboard side, each 63 tons at 14,00 m combinable 126 tons, decreasing

gradually to 2 x 30 tons at 24,00 m . The barge capacity was 3 baco / lash. Until 1984, a successive series of

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almost identical sistervessels were delivered and operated together with further company-owned

conventional tonnage in the world-wide freight market. The Condock III is a 4,400 DWT Ro-Ro, Flo-Flo

vessel with dual 63 metric ton cranes combinable for 126-ton lifts and an unobstructed hold that is 87.5

meters long. The ship is ideal for yachts, tugboats, and modules and can successfully load at facilities

primarily designed for barge operations.

The international track record includes the preparation and transport of sensitive prefabricated high-

dimensioned modules and pressure vessels for refineries and offshore plants in the Ro-Ro mode. Further

contracts include the transport of former USSR Foxtrot class submarine from Australia to Long Beach and

the Dutch sailing- replica BATAVIA from Amsterdam to Sydney and back in the float in/out mode.

These ships have a self-lowering capability whereby a cargo space can be flooded through the stern to allow

direct access of floating cargo. By enabling cargo to be floated into the ship, the need for expensive lifting

gear is eliminated. After loading the barges onto the transport ship it is debalasted to cause it to rise in the

water and the cargo space is drained. The barges then lie in the transport ship as in a dry dock.

The number of barges of a given size which can be docked in a transport ship in this way is dependent on the

length and width of the cargo space. In designing the transport ship the extent to which these dimensions can

be increased is limited by numerous factors including of course the maximum permissible length and beam

of the ship.

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10. FERRYS

A ferry (or ferryboat) is a form of transportation, usually a boat, but sometimes a ship, used to carry

primarily passengers, and sometimes vehicles and cargo as well, across a body of water. Most ferries operate

on regular, frequent, return services. A passenger ferry with many stops, such as in Venice, is sometimes

called a water bus or water taxi.

Ferries form a part of the public transport systems of many waterside cities and islands, allowing direct

transit between points at a capital cost much lower than bridges or tunnels. However, ship connections of

much larger distances (such as over long distances in water bodies like the Mediterranean Sea) may also be

called ferry services, especially if they carry vehicles.

Double-ended

Double-ended ferries have interchangeable bows and sterns, allowing them to shuttle back and forth

between two terminals without having to turn around. Well-known double-ended ferry systems include the

Staten Island Ferry, Washington State Ferries, Star Ferry, several boats on the North Carolina Ferry System,

and the Lake Champlain Transportation Company. Most Norwegian fjord and coastal ferries are double-

ended vessels. Some ferries in Sydney, Australia and British Columbia are also double-ended..

Hydrofoil

Hydrofoils have the advantage of higher cruising speeds, succeeding hovercraft on some English Channel

routes where the ferries now compete against the Eurotunnel and Eurostar trains that use the Channe Tunnel.

Passenger-only hydrofoils also proved a practical, fast and relatively economical solution in the Canary

Islands but were recently replaced by faster catamaran "high speed" ferries that can carry cars. Their

replacement by the larger craft is seen by critics as a retrograde step given that the new vessels use much

more fuel and foster the inappropriate use of carsin islands already suffering from the impact of mass

tourism.

Hovercraft

Hovercraft were developed in the 1960s and 1970s to carry cars. The largest was the massive SR.N4 which

carried cars in its centre section with ramps at the bow and stern between England and France. The

hovercraft was superseded by catamarans which are nearly as fast and are less affected by sea and weather

conditions. Only one service now remains, a foot passenger service between Portsmouth and the Isle of

Wight run by Hovertravel.

Catamaran

Catamarans are normally associated with high-speed ferry services. Stena Line operates the largest

catamarans in the world, the Stena HSS class, between the United Kingdom and Ireland. These waterjet-

powered vessels, displacing 19,638 tonnes, are larger than most catamarans and can accommodate 375

passenger cars and 1,500 passengers. Other examples of these super-sizer catamarans are found in the

Brittany Ferries fleet with the Normandie Express and the Normandie Vitesse.

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Turntable ferry

This type of ferry allows vehicles to load from the "side". The vehicle platform can be turned. When

loading, the platform is turned sideways to allow sideways loading of vehicles. Then the platform is turned

back, in line with the vessel, and the journey across water is made.

Pontoon ferry

Pontoon ferries carry vehicles across rivers and lakes and are widely used in less-developed countries with

large rivers where the cost of bridge construction is prohibitive. One or more vehicles are carried on a

pontoon with ramps at either end for vehicles to drive on and off. Cable ferries (next section) are usually

pontoon ferries, but pontoon ferries on larger rivers are motorised and able to be steered independently like a

boat.

Foot ferry

Foot ferries are small craft used to ferry foot passengers, and often also cyclists, over rivers. These are either

self-propelled craft or cable ferries. Such ferries are for example to be found on the lower River Schelde in

Belgium and in particular the Netherlands. Regular foot ferry service also exists in the capital of the Czech

Republic, Prague. Restored, expanded ferry service in the Port of New York and New Jersey uses boats for

pedestrians only.

Cable ferry

Very short distances may be crossed by a cable or chain ferry, which is usually a pontoon ferry (see above),

where the ferry is propelled along and steered by cables connected to each shore. Sometimes the cable ferry

is human powered by someone on the boat. Reaction ferries are cable ferries that use the perpendicular force

of the current as a source of power.

Air ferries

In the 1950s and 1960s, travel on an "air ferry" was possible—aeroplanes, often ex-military, specially

equipped to take a small number of cars in addition to "foot" passengers. These operated various routes

including between the United Kingdom and Continental Europe. Companies operating such services

included Corsair.

Referrances-http://en.wikipedia.org/wiki/Roll-on/roll-off

http://en.wikipedia.org/wiki/OBO_carrier

http://en.wikipedia.org/wiki/Cargo_ship

Ship design and construction by Taggart

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SPECIFIC GRAVITIES OF LIQUIDS

Liquid Temp kg/cu.m

1,1,2-Trichlorotrifluoroethane 25 C 1564.00

1,2,4-Trichlorobenzene 20 C 1454.00

1,4-Dioxane 20 C 1033.60

2-Methoxyethanol 20 C 964.60

Acetic Acid 25 C 1049.10

Acetone 25 C 784.58

Acetonitrile 20 C 782.20

Alcohol, ethyl 25 C 785.06

Alcohol, methyl 25 C 786.51

Alcohol, propyl 25 C 799.96

Ammonia (aqua) 25 C 823.35

Analine 25 C 1018.93

Automobile oils 15 C 880 - 940

Beer (varies) 10 C 1010

Benzene 25 C 873.81

Benzil 25 C 1079.64

Brine 15 C 1230

Bromine 25 C 3120.40

Butyric Acid 20 C 959

Butane 25 C 599.09

n-Butyl Acetate 20 C 879.60

n-Butyl Alcohol 20 C 809.70

n-Butyl Chloride 20 C 886.20

Caproic acid 25 C 921.06

Carbolic acid 15 C 956.30

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Carbon disulfide 25 C 1260.97

Carbon tetrachloride 25 C 1584.39

Carene 25 C 856.99

Castor oil 25 C 956.14

Chloride 25 C 1559.88

Chlorobenzene 20 C 1105.80

Chloroform 20 C 1489.20

Chloroform 25 C 1464.73

Citric acid 25 C 1659.51

Coconut oil 15 C 924.27

Cotton seed oil 15 C 925.87

Cresol 25 C 1023.58

Creosote 15 C 1066.83

Crude oil, 48° API 60 F 790

Crude oil, 40° API 60 F 825

Crude oil, 35.6° API 60 F 847

Crude oil, 32.6° API 60 F 862

Crude oil, California 60 F 915

Crude oil, Mexican 60 F 973

Crude oil, Texas 60 F 873

Cumene 25 C 860.19

Cyclohexane 20 C 778.50

Cyclopentane 20 C 745.40

Decane 25 C 726.28

Diesel fuel oil 20 to 60 15 C 820 - 950

Diethyl ether 20 C 714

o-Dichlorobenzene 20 C 1305.80

Dichloromethane 20 C 1326.00

Diethylene glycol 15 C 1120

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Dichloromethane 20 C 1326.00

Dimethyl Acetamide 20 C 941.50

N,N-Dimethylformamide 20 C 948.70

Dimethyl Sulfoxide 20 C 1100.40

Dodecane 25 C 754.63

Ethane -89 C 570.26

Ether 25 C 72.72

DIFFERENT DRAUGHTS

air

draught the vertical distance measured from the ship'swaterline to the highest point on the

ship; usually comes into consideration when the ship has to sail under overhead

bridges in the river

compare draught

bar

draught maximum draught which a ship can take to pass over a bar or sand bank

design

draught draught as used for design calculation before actual construction, which has a

tendency to distort the final reading

draught

marks figures welded on the bow, midship and sternof each side of a ship's shell plating

to indicatedraught; the distance is read from the lower edge of each

number; draught measured at the bow is called forward draught and at the stern

is called aft draught

draught

survey survey carried out to determine the cargo weight on board by measuring the

ship'sdraught

extreme

draught draught measured to the lowest projecting portion of a ship

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forced

draught combustion air for boiler furnace supplied under pressure from a

forced draught fan

lightship

draught draught when ship is empty and deadweightis zero

Different Types of Cargoes on a Ship

Cargoes are goods transported on different carriers/vehicles/means of transport from one place to another for

economic reasons. Generally cargo is used for goods transported through air or water. There are different

types of cargoes that can be transported through ship for commercial purposes. The cargo’s transported by

ship are handled at seaport terminals. Some of these goods are discussed below:

Heavy Equipments and Machinery: This includes industrial as well as household machinery, automobiles,

technical machinery, engineering machinery, auxiliary machinery; etc. They are packed either on wooden

crates or in heavy steel/iron containers according to their handling instructions.

Dangerous or Hazardous Cargo: They consist of hazardous materials like chemicals, oil, petrol, and

diesel, asbestos which are harmful for human contact. Very careful handling is a must to avoid accidents and

loss to human life.

Inflammable or Combustible Cargo: They include goods like oil seeds, oil, diesel, cotton, jute which are

susceptible to catch fire easily even from a single flame. They can ignite spontaneously and hence must be

handled with double extra care to avoid loss of material and men.

Concentrates/Ores: This type of cargo is of high density and may emit toxic fumes and can deplete oxygen

inside the tank. They are usually present in huge quantities and must be prevented from moisture.

Bulk Cargo: They generally include goods like scrap metal, alumina, grains, wood chips, gypsum, logs,

salt. They are generally large in quantities and need special handling care.

Food Products: They include frozen meat, sea food, frozen fruits and vegetables, canned and tinned food

items, syrups, jams, pickles, jellies and fresh food products, grains etc. Temperature and moisture level to be

regulated as per requirements and proper storage as well to minimize loss.

Military Equipments and Project Cargo like Windmills, Generators, Air conditioners:They are usually

too large to fit into any containers.

Leather Hides: usually such types of cargo produce strong malodors and hence have to be kept in isolation

especially when hides are soaked in salt.

Fragile Items: They include items like glassware, china wear, clay items and small machinery and tools

which need to be loaded, transported and unloaded with extra care. They must be packed too with extra care.

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Ores/concentrates - these are high-density cargoes and are usually loaded in large quantities on a ship. The

main danger from these cargoes is that they could give rise to toxic vapours that could make the atmosphere

of the tank depleted in oxygen. Hence care should be taken while entering such cargo spaces and these

cargoes should be kept separate from other moist cargoes lest they develop a flow state.

Leather Hides -leather can be a very unpleasant cargo to carry on board a ship and it gives out a very strong

smell which is literally unbearable especially in enclosed spaces. When the hides are soaked with salt they

give out a large amount of brine, so this type of cargo has to be kept in isolation from other cargoes.

Foodgrains - ships are used to transport large amounts of food grain from one place to another and these

include grains such as rice, wheat, seeds and so forth. Needless to say such a cargo needs to be stored in very

sanitized conditions and there is no question of a there been any contact between such cargoes and other

cargoes mentioned previously such as leather. Apart from foodgrains ships can also carry other types of

eatables and these may well require refrigeration to keep them fresh throughout the voyage.