Ship design and construction

In ship terminology, the “hull” is the protective shell enclosing a ship’s cargo, machinery, and living spaces. The “machinery” includes engines, electrical systems, and winches. The “stern” is the rear, while the “bow” is the forward part. “Amidships” refers to the middle. The “beam” is the width at the waterline. The “engine room” houses the propulsion machinery. A “propeller shaft” transmits power to the propeller. A “bow thruster” aids maneuvering. The “rudder” steers the vessel. A “bulbous bow” is a protruding bulb below the waterline. The “hold” is the space for cargo.

ship design and construction

Various examples illustrate ship-related terminology and scenarios. A “trimaran hull” allows a ship to carry weapons and land helicopters. A Union blockade during a historical event affected the availability of ship machinery. A ship can be severed at the stern end. Breakers loom on the starboard bow during an incident. A buoy line is attached where the forward section breaks from the bow. Damage from an iceberg is at the bow. “Maximum beam” refers to the ship’s width. Watertight bulkheads separate crew quarters from the engine room. Turbines drive propeller shafts. A “bow thruster” aids in crowded areas. Rigging and hull construction impact ship design, and a bulbous bow increases speed. Water leaks into the cargo hold.

ship design and construction 1

Structural members of a ship

In ship construction, various terms denote critical components and structural elements. The “shell plating” serves as the outermost layer of a ship’s hull, forming the vessel’s exterior. A “strake” refers to a horizontal row of hull plating. The “keel” represents the ship’s bottom structural member. “Deck” is the permanent covering where the crew stands. The “tank top” is the lowest horizontal surface, often part of bilge tanks. “Floor” comprises transverse stiffeners on the ship’s bottom. “Stringer” is a fore-and-aft girder along the shell or deck. “Buoyancy” is the upward hydrostatic force on the hull. “Strength” is the quality of being firm. “Stability” is a ship’s ability to float upright. A “bulkhead” protects against cargo shifts. A “compartment” is a defined space between decks and bulkheads. The “stem” is a boat’s forward part. “Frame” represents transverse ribs. “Beam” is a ship’s width. “Bracket” supports the tank top. A “girder” is a longitudinal member at the ship’s bottom. “Stern post” is the upright member at the stern. “Stiffener” reinforces bulkhead plating.

structural members of a ship

    1. bulwark rail
    2. bulwark stay
    3. spur
    4. beam knees
    5. spar ceiling
    6. frame
    7. bilge keel
    8. reverse frame
    9. lightening hole in tank side bracket
    10. limber boards
    11. floor
    12. tank top plating
    13. manhole cover
    14. garboard strake
    15. keel plate
    16. intercostal
    17. margin plate
    18. bilge strake
    19. sheer strake
    20. bulwark
    21. upper deck plating
    22. upper deck beam
    23. centreline bulkhead
    24. main deck plating
    25. main deck beam


Examples of use:

  • The strakes were enclosed by transverse bulkheads of the same thickness.
  • A steel keel provides an added moment to maintain the vehicle in an upright pose.
  • We sat on deck until it was dark.
  • The water tanker version lacks the raised cargo expansion tank top amidships, and both can carry 600 tons of cargo.
  • In smaller ships, the plate floors themselves act as the stiffening members of the bottom shell plating.
  • One of the locations where stringer is mostly used is the forward part of the ship.
  • Flotation suits are very popular now with boat anglers and have benefits of limited buoyancy and warmth.
  • This suggests that I want a boat with a reserve of secondary stability and a low windage for longer trips.

structural members of a ship 1

Ship’s equipment

Basic terms: Key terms in ship design and operations include “cargo gear,” equipment for handling cargo, and “derrick,” a lifting device. “Lifting capacity” indicates the maximum safe weight. A “winch” adjusts rope tension. “Shore crane” aids cargo loading at terminals. The “mast” is a vertical spar on a ship. The “bridge” is the command platform. “Crew accommodation” includes cabins. “Life-saving apparatus” protects lives at sea. “Draught” is a ship hull’s vertical distance to the waterline. The “waterline” is where the hull meets water. “Freeboard” is the waterline-to-deck distance. A “samson post” supports a ship’s deck beam.

ships equipment

Examples of use:

  • The handling of cargo is carried out either by the ship’s own cargo gear or by shore cranes.
  • Derrick cranes are made of all powers, from the timber I-ton hand derrick to the steel 150-ton derrick used in shipbuilding yards.
  • The maximum lifting capacity is just over two tons.
  • The line is hauled in by a steam or electric winch, and the sounding-tube containing a sample of the bottom deposit is rapidly brought on board.
  • The lowest sail on a mast of a square-rigged ship.
  • The bridge of a vessel is the navigating centre of the ship where her course is determined.
  • At the head of an excellent harbour, a deep inlet about a mile long, available for ships of the deepest draught.



In shipping, a “liner” is a vessel on a regular scheduled service between ports. “Service” involves transporting goods on high-capacity, ocean-going ships with fixed schedules. “Accommodation” refers to providing rooms and food. A “shipowner” owns one or more ships. “Gear” refers to tools or apparatus. “General cargo” includes ordinary goods transported on ships. A “fixed route” indicates a transportation service without deviations. “Coastal trade” involves transporting goods or passengers between ports of different countries. “Deep-sea trade” covers cargo and passenger vessels on high seas or long voyages. “Cargo handling” is the movement of goods on and off ships. A “vehicle ferry” transports vehicles and passengers across rivers or short sea stretches. A “sailing schedule” lists ships, voyage numbers, ETA, ETD dates, and ports of call in a liner service.


Examples of use:

  • Large liners from Liverpool, Southampton, London, Hamburg, Havre and Antwerp call regularly for passengers or cargo at Leixoes or Lisbon, or both ports, on their way to and from South America.
  • These are vessels that operate on a regular scheduled service between groups of ports.
  • A hotel, motel and inn are each an example of an accommodation for travellers.
  • After an apprenticeship in a counting-house, he led a seafaring life for several years, and became a shipowner and merchant.
  • The “Endeavour” struck heavily, and fell over so much that the guns, spare cables, and other heavy gear had at once to be thrown overboard to lighten the ship.


A “tramp” is a merchant vessel with no fixed route or schedule. “Bulk cargo” refers to loose cargo loaded directly into a ship’s hold, such as grain or coal. “Shipload” is the maximum cargo or people a ship can carry. “Conveyance” is the transportation process. A “charter party” is an agreement for ship hire and cargo delivery. “Draft” is the loaded vessel’s depth in the water. “Beam” is the ship’s width at the widest point on the waterline. “Deadweight tonnage” is the total weight a ship can carry. Abbreviations include G.R.T. (gross register ton), N.R.T. (net register ton), and Cu. Ft. (cubic feet), a unit of volume.


Examples of use:

  • The collections comprise objects from all over Wales but there is a leaning toward Cardiff ‘s once-extensive tramp shipping industry.
  • The first shipload of grain that came for the starving Irish was from India.
  • Formerly of some importance, the harbour can no longer be entered by large vessels, and goods are transhipped into flat-bottomed lighters for conveyance

Liquid and dry bulk cargo ships

A “tanker” is a specialized cargo ship for liquid bulk. “Turn-round” is the time to prepare a vessel for a return trip. “Return cargo” is brought back in place of goods sent out. “Chemical carriers” transport noxious liquid substances. “Product carriers” are oil tankers for products other than crude oil. “Dry bulk ships” carry solid goods with heat/cold tolerance. “Shipment” is shipping goods or a consignment. “Water ballast” adds stability during transit. “Cargo handling gear” includes cranes and conveyors. “Barge carriers” transport bulk goods in shallow waters. Abbreviations: LNG (liquefied natural gas), LPG (liquefied petroleum gas), F. (Fahrenheit).

liquid and dry bulk cargo ships

Examples of use:

  • Everyone can remember seeing photographs of oil covered birds following an oil tanker
  • It is designed to deal with bulk liquid cargoes permitting quick loading and discharge, thereby ensuring the fast turn-rounds so essential to good utilization.
  • Patent fuel is largely sent to South America, whence return cargoes of mineral ores and grain are obtained.
  • A type 1 ship is a chemical tanker intended for the transportation of products considered to present the greatest overall hazard and type 2 and type 3 for products of progressively lesser hazards.
  • As defined in MARPOL Annex II, chemical tanker means a ship constructed or adapted for carrying in bulk any liquid product listed in chapter 17 of the International Bulk Chemical Code.

Break bulk cargo ships

“Break bulk cargo” refers to goods loaded individually, not in containers or bulk. “Roll-on/roll-off vessels” transport wheeled cargo driven on and off. “Container vessels” carry load in intermodal containers. “Fruit carriers” have refrigeration for perishables. “Reefer ships” transport temperature-sensitive goods. “Timber carriers” move logs and beams. “Heavy lift ships” handle large loads. Collocations include offering services, eliminating cranage (crane use), reducing pilferage (theft), conveying cargo, and facilitating cargo handling.

break bulk cargo ships

Examples of use:

  • The volume of break bulk cargo has declined dramatically worldwide as containerization has grown.
  • RORO ships have been increasing in size, and some ports have had trouble handling them because the harbours are not deep enough.
  • Container ships are a common means of commercial intermodal freight transport and now carry most seagoing non-bulk cargo.
  • The most noteworthy characteristic about the fruit carrier is the storage module devised to successfully transport the intended cargo.

Specialized craft

A “tug,” or tugboat, maneuvers vessels by pushing or towing them. A “towing hook” quickly connects to a tow and reduces heeling moments on the tug. A “towline” is a line used for towing. “Fittings” are removable equipment fixed to something. A “towbeam” prevents the towline from fouling after-deck fittings. “Salvage tug” rescues distressed or sinking ships. “Distress signals” seek help, while a “disabled ship” is damaged or impaired. “Controllable pitch propellers” change blade pitch, and “Kort’s nozzle” is a marine propeller with a non-rotating nozzle. “Oil rig supply vessels” serve offshore platforms. “Offshore rigs” explore, extract, and process petroleum. “Icebreakers” navigate ice-covered waters. “Dredgers” remove sand or sediment, with “grab/bucket dredgers” using a crane-operated grab. A “pontoon” relies on floats, and a “slewing/hoisting crane” lifts and rotates loads. “Hoppers” are used for maintenance dredging. “Barges” transport bulk goods, while “trawlers” are fishing vessels operating trawls. “Sturdy vessels” are strong and durable. “Fish factory ships” process and freeze caught fish. “Seiners” specialize in seine-haul fishing. “Craft” refers to smaller boats, often engaged in loading or unloading other vessels.)

specialized craft

Examples of use:

  • Five tugboats hauled the tanker off the rocks and into deeper water.
  • The fixed or spring-loaded towing hook is at the after end of the superstructure.
  • Captain Hiller quickly backed the ship, and the cable was paid out to reduce towline
  • Towbeams are fitted so that the towline does not foul the after-deck fittings.
  • Dreadnought’s anchor had come up easily enough when the salvage tug came to dispose of her.
  • Send out a distress signal; the ship is sinking!
  • When a distress call is received, the tug and others who have heard the signal, race to the disabled ship to compete for the salvage work.
  • The blade angle of controllable pitch propeller should be examined and adjusted.
  • The grab dredger is in its simplest form a pontoon with a slewing and hoisting crane capable of operating a double-chain grab.


Deck department

The “deck department” on naval and merchant ships organizes shipboard activities. The “catering department” or galley handles food preparation and service for the crew. “Manning” is the process of providing personnel for a job, including “ratings,” non-officer seamen. The “master” or captain is the top officer, with the “chief officer” or chief mate being next in rank. A “certificate of competency” is issued to seafarers based on examinations. A “master mariner” holds the highest deck officer qualification. Other “mates,” such as Chief Officer, Second Officer, and Third Officer, assist the master. “Deck officers” manage navigation, manoeuvring, cargo handling, and lifesaving devices. “Navigating officers” determine a ship’s position using various methods. A “boatswain” supervises seamen, while a “carpenter” specializes in shipboard woodwork, and a “shipwright” builds and repairs vessels. “Apprentices” learn a trade, and “sailors,” “seamen,” and “seafarers” work on ships, with the latter encompassing all maritime travelers.

deck department

Examples of use:

  • The organization of ships is changing but it is still customarily to find deck, engine-room, catering and radio departments in ships of a traditional type.
  • Low unemployment, a competitive job market and difficulties in recruiting and retaining sailors created the manning
  • General purpose manning is a system under which the ratings are deployed on duties throughout the ship.
  • The master gave the order to abandon ship.
  • It is probable that the chief officer will hold a similar qualification as the master although the law requires him to have a first mate’s certificate
  • My father, who was a well-qualified master mariner, was unemployed for four years in the 1930s.
  • The expression “mate” and “officer”, when referring to deck officers, are synonymous.
  • At sea, navigating officers are responsible for the piloting of seafaring vessels.

Radio and engine room department

The “radio department” handles shipboard radio provisions, led by the “radio officer” responsible for all radio communications. “Electronic aids” facilitate electrical appliance operation. A “message” conveys information, news, or requests, often using “distress signals” in emergencies. “Watchkeeping” assigns sailors specific roles for continuous ship operation. The “engine-room department” oversees propulsion and support systems, with “engineer officers” managing material conditions. The “chief engineer” leads the engine department on a ship. A “staff” is a group executing an establishment’s work. The “electrical officer” ensures electronic and electrical gear operational security and effectiveness on the vessel.

radio and engine room department

Examples of use:

  • The radio-department often consists of only one man and so the term “department” may seem out of place.
  • The provision of the radio is a legal requirement and so is the carriage in vessels of a certified radio-officer.
  • This factsheet outlines your options when selecting an electronic aid to make it clearer and quicker to communicate.
  • Her manipulations are interrupted by a distress signal from a ship that has run onto the reef just off the coast.
  • Following the first complement job a junior officer may be further employed in bridge watchkeeping duties in ships or submarines or may sub-specialise.

radio and engine room department 1


Conventional cargo stowage

conventional cargo stowage

“Dunnage” refers to materials like wooden planks placed at the cargo hold’s bottom to raise and protect cargo. “DBB” stands for deals, boards, and battens. “Lockups” are secure cargo hold parts for valuable cargo. “Broken stowage” is space unusable due to cargo type or structural interferences. “Battening down” is watertight hatch closure. “Hatch coaming” are raised plates around a hatch. “Hatchway beams” are steel beams laid thwartships. “Tarpaulins” are waterproof canvases for hatch covering. “Shore gang” includes a gang foreman, hatchwayman, winchman, and stevedores. “Tally clerk” checks each cargo part. “Shifting boards” prevent grain shifting. “Homogeneous cargo” has an equal stowage factor. “Cargo plan” marks cargo locations on board. “Leakage” is fluid entrance or escape through a hole. “Drainage” is gradual drying or emptying. “Moisture” is dampness, and “contamination” is making something impure. “Taint” is cargo impregnation, “chafe” is wear by rubbing, and “vermin” are small noxious animals. “Wastage” is loss, “pilferage” is petty theft, and a “package” is unitized cargo. A “parcel” is a departed cargo part, “consignment” is shipped goods to a consignee, and “shipment” is goods sent by sea. A “shipload” is a full ship load.

Loading a vessel

Damage to cargo” refers to contamination, deterioration, or loss. “Deterioration” is decay or degradation. “Negligence clause” attempts to relieve shipowners of liability for losses caused by negligence. “Measurement” is the extent ascertained by measuring. “Stowage” is the space or act of placing goods. “Dunnaging” places material to raise cargo, preventing shifting. “Handling” is the method of moving something. “Stevedore” loads and unloads cargo. “Safety of the ship” ensures crew, cargo, and marine environment safety. A “stable and seaworthy ship” is fit for its purpose. “Compartment” is a space created by watertight bulkheads. “Shifting” is moving from one place to another. “Sweating” is exuding moisture. “Broaching of cargo” is submitting cargo. “Trim” is the difference between forward and after draughts. “Draught marks” indicate maximum loading draughts. “Heel” is temporary inclination due to external forces. “List” is a permanent inclination. “Load lines” indicate maximum permissible draughts, also known as Plimsoll marks.

loading a vessel

Examples of use:

  • Damage to cargo caused by improper packaging can be offset by insurance.
  • The master and the officers of all vessels require a good working knowledge of the various kinds of cargo they are likely to carry: their peculiar characteristics, liability to damage, decay, or deterioration, their measurement, and the usual methods of packing, loading and discharging, stowage, dunnaging, etc.
  • The actual handling of the cargo in loading and discharging is done by stevedores.
  • The Master is responsible for the safety of the ship and cargo, and he must supervise the work of the stevedores for the general safety.
  • The increase in trim by the stern assumed by a vessel when running at high speed over that existing when she is at rest.

Leaving the dock

A “Dock Pilot” avoids other ships, considering the transverse thrust of the screw and wind. A “River Pilot” guides ships along rivers, factoring in tides and currents. A “tug” tows vessels, known for manoeuvrability and engine power. “Transverse thrust” is the sideways force from the propeller, like the ‘paddle wheel effect.’ “Effect of the screw” refers to the propeller’s impact. “Singling up” releases all lines except one from ship to pier in each mooring position. “Mooring ropes” are lines fixed to vessel fittings. A “skipper” is another term for a ship’s master. “Handling of ships” involves proper control, especially in harbours. A “buoy” is a floating device. “Dolphin” is a structure for mooring vessels. “Slack water” is the tide’s turning state. “Stemming the tide” slows or stops the increase. “Dockside” is the area next to a dock. The “stem of the ship” is the foremost structure where hull plating attaches. The “stern of the ship” is the after end, described by cross-sectional shape like counter stern or transom stern. “Bow” is opposite the stern.

leaving the dock

Examples of use:

  • Before a Pilot (Dock or Sea Pilot) takes a ship through the basins he will want to know how she steers, the working of her engines and how much power she develops when going astern, her draught.
  • Thrust of a screw propeller produces a local strain on that part of the ship to which the thrust block foundation is attached.
  • The Fore and Aft Mooring parties will single up lines to Masters orders and Pilots advice.
  • You take a mooring rope forward and behind the mooring cleat to reduce the potential for the boat to swing back and forth.
  • The yachts are moored on swing moored on swing moorings, attached to a buoy in the harbour, not moored alongside a jetty.


“Underway” means not anchored or aground, indicating movement through water. “Alongside” is close to a ship’s side or a wharf. “Watch-keeping duties” involve assigning sailors specific roles for continuous ship operation. “Lookout” entails vigilant observation to avoid danger. “Steering” is controlling a vessel’s direction. “Passage plan” is a berth-to-berth guide for the most favorable route. “Pilotage waters” are areas requiring a maritime pilot’s services. “Drills” are training exercises. The “chart room” is where ship charts are consulted. “Relieve a watch” is taking over someone’s duties. “Traffic separation scheme” (TSS) is a regulated maritime route system. “Traffic report” provides local traffic information. “Weather & visibility report” offers weather and visual range details. “Navigational aids report” covers markers aiding navigation. A “helmsman” steers a maritime vessel.


Examples of use:

  • The procedures when underway mostly involve the watch-keeping duties of the officers and ratings.
  • The commercial quays are built in deep water and permit the mooring alongside of the largest vessels.
  • One might as well attempt to steer a boat carried along by currents of water in the absence of oars, sails and wind, as to steer a balloon carried along by currents of air.
  • Production of a passage plan prior to departure is a legal requirement.



Join 17,460 active seafarers

Subscribe and get free weekly maritime updates on news, tech, and regulations. Sign up now for fresh knowledge.

Please enter a valid email address
That address is already in use
The security code entered was incorrect
Thanks for signing up