General cargo ship

The general cargo ship is a sea-going vessel designed to carry mixed consignments that cannot be aggregated into a single homogeneous commodity requiring a specialist hull form. A single voyage may include bagged fertiliser in lower holds, palletised consumer goods in tween-decks, timber on deck, and a breakbulk transformer secured on a strengthened tank-top. This versatility distinguishes the general cargo ship from the bulk carrier, the tanker, and the cellular container vessel, all of which are optimised for one cargo mode. The type was the dominant ocean carrier in the two decades following the Second World War, handling virtually all manufactured goods traded internationally before containerisation restructured the industry from the mid-1960s onward. Today the general cargo ship and its direct descendant, the multipurpose vessel (MPV), account for roughly eight per cent of world fleet gross tonnage, a share that has declined steadily since 1980 but that has stabilised because the segment retains a structural role: serving ports without quay cranes, carrying project and heavy-lift cargoes that cannot be containerised, and operating liner services into smaller West African, South American, and Pacific island markets. ShipCalculators.com provides a range of tools for this vessel type, including the General / Multipurpose Cargo calculator and the Heavy-lift / Project Cargo calculator.

Contents

History and development

The pre-container era

The general cargo ship in its classic form was a direct descendant of the nineteenth-century tramp steamer. By 1900, ocean-going cargo vessels had settled on a pattern that would persist for sixty years: a single-screw steam reciprocating or turbine plant amidships, four to six cargo holds fore and aft of the machinery space, and a rig of derricks worked from king posts or goalpost masts. Holds were arranged on two or three levels separated by intermediate decks known as tween-decks, which allowed heavy goods such as machinery and raw materials to be loaded in the lower hold while lighter, fragile, or high-value cargo was stowed in the tween-deck space above.

The United States wartime shipbuilding programme of 1941 to 1945 produced approximately 2,710 Liberty ships to a standard design based on a British tramp steamer template. The Liberty ship displaced roughly 14,000 tonnes fully loaded, was 134 m long, carried five holds served by 15 to 25 derricks, and became the de facto global cargo-ship standard for the late 1940s and 1950s. When the Liberty fleet aged, a generation of purpose-built replacements followed. British yards, notably Austin and Pickersgill of Sunderland, developed the SD-14 (Shelter Deck 14) design from 1967, a 14,000 dwt shelter-deck vessel that sold over 200 units to Greek, Brazilian, and other operators. The shelter-deck configuration gave the ship a legally unclosed upper deck, which reduced the measured tonnage used as the basis for port dues and canal fees under the 1969 Tonnage Convention rules then in force.

Simultaneously, Scandinavia and Germany developed the ’tweendecker for liner service - vessels operating on fixed-route schedules between named ports, loading small parcels of general cargo for multiple consignees at each call. Nordic, North German Lloyd, Hamburg Süd, and Hapag-Lloyd each operated large fleets of medium-sized geared general cargo ships on these liner routes throughout the 1950s and 1960s.

Containerisation and displacement, 1966-1985

Malcolm McLean’s Sea-Land Service began the first transatlantic container service in 1966 aboard converted vessels, and the purpose-built fully cellular container ship followed rapidly. By 1975, the North Atlantic, North Pacific, and Europe-Australia trades were effectively containerised, and by 1985 container ships dominated all major long-haul general cargo trades. The effect on the general cargo fleet was severe: operators who did not convert to cellular vessels or to purpose-built container tonnage found their conventional ships progressively uncompetitive on voyage economics, turnaround time in port, and cargo security.

Between 1975 and 1995, hundreds of tween-deck general cargo ships were scrapped or laid up. Some trades shifted permanently to containers; others moved to ro-ro ferries. The liner services that had sustained the classic general cargo ship contracted to a residual of niche routes where container infrastructure was absent or where cargo characteristics made unitisation impractical.

The multipurpose vessel generation, 1990s to present

Industry response to the container revolution produced the multipurpose vessel (MPV) - a vessel designed from the outset to handle containers in cellular guides, breakbulk on tank-tops and tween-decks, timber on deck, and oversized project cargo in large open hatches. MPVs differ from classic tween-deckers principally in having larger hatches (often wide enough for single-lift operations on oversized machinery), stronger tank-tops (typically 10 to 25 tonnes per square metre to accept heavy-lift cargo), higher-capacity deck cranes (30 to 150 tonnes safe working load in standard form), and container guides in holds allowing carriage of 20-foot and 40-foot units. Typical MPVs range from 8,000 to 15,000 dwt, though units from 5,000 to 25,000 dwt have been built.

German shipping groups were early movers: Peter Döhle, Rickmers-Linie, Briese Schiffahrt (operating under the BBC Chartering commercial name), and AAL Shipping (Ahrenkiel Allgemeine Linienschiffahrt) developed purpose-built MPV fleets in the 1990s and 2000s. Chipolbrok, the joint Chinese-Polish venture formed in 1951, operated a mixed fleet of project carriers on Asia-Europe and Asia-Americas routes. Maersk Line operated MPV tonnage briefly but withdrew from that market in 2012, electing to consolidate its general cargo exposure through conventional container and ro-ro tonnage.

The 2008 financial crisis and the ensuing contraction in global infrastructure investment reduced project cargo volumes sharply, causing a period of significant overcapacity in the MPV and HLV segments between 2013 and 2016. Several operators, including Rickmers-Linie and Hansa Heavy Lift, entered insolvency during this period. The subsequent recovery, driven by offshore wind farm construction, LNG plant construction in emerging markets, and power sector expansion across Africa and Southeast Asia, absorbed surplus tonnage and returned the segment to moderate profitability by the early 2020s.

Types and subtypes

Tween-deck vessel

The tween-deck vessel is the oldest sub-type, characterised by at least two levels of cargo space within each hold, separated by an intermediate deck that can be fitted with portable hatch covers or removed entirely to create a full-height single hold. The intermediate deck allows a ship’s officer to separate cargoes by weight (heavy goods on tank-top, lighter goods above), by compatibility (food away from chemicals), or by destination (goods for the first port of call stowed last and accessed first). Tween-deck vessels built in the 1960s and 1970s typically had four or five holds, overall lengths of 130 to 160 m, and deadweights of 10,000 to 18,000 tonnes. Many were fitted with a single set of sampson posts amidships serving a union-purchase rig of two derricks whose combined capacity was greater than either derrick alone.

Multipurpose vessel

The contemporary MPV consolidates the flexibility requirements of tween-deck vessels with container handling and heavy-lift capability. A typical MPV has three or four holds, each served by a 30 to 60-tonne slewing deck crane. Hatch dimensions are large relative to beam - often 80 to 90% of beam width - to facilitate side-loading of out-of-gauge cargo and to allow forklift operation on the tween-deck. Tank-top strength of 15 to 25 t/m² is standard on the larger units. The BBC carrier class operated by BBC Chartering represents this type well: BBC vessels of 12,500 to 17,000 dwt carry four cranes of 40 tonnes each combinable to an 80-tonne tandem lift and can load 45-foot containers.

Heavy-lift vessel

The heavy-lift vessel (HLV) is a sub-type distinguished by installed lifting gear capable of handling single lifts from roughly 100 tonnes to several hundred tonnes. Operators in this segment include SAL Heavy Lift (formerly Schiffahrtskontor Altes Land), BigLift Shipping, Jumbo Shipping, dship Carriers, AAL, and BBC Chartering’s Briese Group. Typical HLVs are 8,000 to 20,000 dwt with one or two mast cranes or A-frame systems capable of 300 to 700 tonnes at rated radius. The Stulcken heavy-lift derrick, developed by the Hamburg yard Stülcken Werft, achieved safe working loads of up to 650 tonnes from a single bipod mast and was widely fitted to vessels of the 1950s and 1960s; the type is rare on newbuilds today but survives on older tonnage. Modern heavy-lift vessels carry hydraulic pedestal cranes rather than derricks, and tandem-lift procedures combining two cranes can extend lifting capacity to 900 tonnes or more.

The semi-submersible heavy-lift vessel represents a separate category within this group. Dockwise Vanguard, built in 2012 at roughly 117,000 dwt and 275 m in length, operates by partially submerging its deck to float a cargo - which may be another ship, an offshore platform, or a large construction module - over the lowered deck, then deballasting to lift the cargo clear of the water. This approach enables transport of items far too large for conventional crane handling.

SD-14 and Liberty-replacement types

The SD-14 was a designed Liberty-ship replacement produced from 1967 by Austin and Pickersgill at Sunderland under licence to various foreign builders. Its shelter-deck arrangement, single Doxford opposed-piston engine, and standardised construction made it economical to build and operate. The SD-14 influenced a generation of British and international tramp tonnage; comparable designs included the Japanese Freedom-type, the Canadian SCAN-design vessels, and various Scandinavian standard-cargo types of the 1970s.

A total of 211 SD-14s were completed between 1967 and 1982. The type became so strongly associated with the Greek tramp trades that a substantial number passed through Piraeus ownership during the 1970s and 1980s. Its successor intended by Austin and Pickersgill, the SD-18, reached only prototype stage before the collapse of British tramp shipbuilding in the early 1980s. The corresponding German standard design of the era was the “Hamburger Standardschiff” series developed by Deutsche Werft and Blohm and Voss in the 5,000 to 10,000 dwt range, aimed at routes with smaller port restrictions.

Ice-class general cargo ships

A subset of MPVs and general cargo vessels operates in ice-affected waters under Finnish-Swedish Ice Class (IA, IB, IC) or Russian Maritime Register of Shipping (Ice1, Ice2, Arc4) notations. These vessels carry reinforced bows, additional framing, and higher-power propulsion to maintain schedules on routes such as the Baltic in winter, the Russian Arctic, and Canadian Great Lakes. The Polar Code of 2017 imposes additional requirements on ships operating in Arctic and Antarctic waters, including an ice class notation, environmental standards for discharges, and voyage planning obligations. Loading in ice conditions involves additional stability allowances for topside ice accretion calculated against IACS standards, which can be checked with stability tools available at ShipCalculators.com.

Hull form and structural arrangement

Principal dimensions and form coefficients

General cargo ships and MPVs tend toward fuller form coefficients than container ships but finer than bulk carriers. A block coefficient Cb in the range 0.65 to 0.72 is typical for vessels of 12,000 to 18,000 dwt designed for service speeds of 14 to 17 knots. The block coefficient governs the relationship between a hull’s enclosed volume and its bounding rectangular box: Cb = V / (L × B × T), where V is displaced volume, L is length between perpendiculars, B is moulded breadth, and T is draught. The Block Coefficient (Cb) calculator and Tonnes per Centimetre Immersion calculator support standard loading calculations for these vessels. The DWT vs GT capacity picker converts between deadweight and gross tonnage for quick charter assessments.

Hatch arrangement and dimensions

Hold hatches on general cargo ships are characterised by their large size relative to hold volume - a deliberate design choice to facilitate break-bulk cargo operations where individual items must be swung in and out by crane or derrick. A typical MPV of 12,000 dwt has three or four hatches measuring 15 to 25 m in length and 10 to 15 m in width. Hatch covers are usually of the folding-type (McGregor or equivalent), hydraulically operated, rated to support deck cargo at 1.75 t/m² or above. Hatch cover structural adequacy is governed by IACS Unified Requirement S26 and S21; the IACS UR S26 Hatch-Cover Design Pressure calculator and the IACS UR S21 Hatch Cover Deflection Limit calculator address these requirements directly, and the Hatch Cover Design Pressure (IACS UR S21A) calculator handles the design loading calculation.

Double bottom and tank-top

The double bottom of a general cargo ship serves the same structural and ballasting function as in other cargo types. On MPVs and HLVs, the inner bottom (tank-top) is structurally significant because heavy-lift and project cargoes impose point or line loads far exceeding the 2 to 5 t/m² typical of bulk cargoes. Tank-top allowable loads on MPVs are typically 10 to 25 t/m², and classification society rules specify minimum floor spacing and plating thickness to achieve these values. The IACS UR S34 Loading calculator applies to the loading condition checks for such vessels.

Point loads from the feet of machinery, jack stands, or grillage beams supporting heavy-lift items often exceed the continuous area load rating of the tank-top. In such cases, the load is spread over a grillage of steel beams welded to the tank-top plating, and the effective pressure at the inner bottom is verified against the classification society’s point-load rules. The grillage design forms part of the engineering documentation package submitted for classification society approval alongside the cargo securing plan.

Holds and tween-deck framing

Hold framing on general cargo ships is typically transverse below the tween-deck and longitudinal above the waterline in the topside structure, a mixed arrangement that provides adequate transverse stiffness against hold flooding loads while meeting longitudinal strength requirements. Tween-deck beams are removable on most vessels to allow full-height single-compartment loading for tall or heavy-lift items; the tween-deck plating in the stowed configuration supports the intermediate cargo tier. Pontoon-type tween-deck covers, each panel handling by the ship’s crane, are common on MPVs; they can be shifted to one side of the hold to create a half-width working area where cargo of different heights is loaded in stages.

Crew accommodation and machinery arrangement

Most general cargo ships built since the 1970s have adopted the aft superstructure and aft machinery arrangement, which maximises clear hold length, reduces the interference between crane jibs and king posts amidships, and allows a larger number of holds relative to overall length. The aft arrangement places the bridge at the stern, which imposes limits on forward visibility from the navigation bridge that must be demonstrated to meet SOLAS Chapter V requirements. Some MPVs retain the midships bridge arrangement to improve visibility for cargo operations, particularly when working cranes forward and aft simultaneously.

Cargo handling equipment

Derrick systems

Derricks remain the cargo handling equipment of choice on many older general cargo ships and on vessels trading to ports where shore-side equipment is absent or unreliable. The simplest arrangement is the union-purchase system: two derricks, each topped from the same cargo mast king post, with the swinging whip of one leading over the hatch and the swinging whip of the other positioned over the quay. When both runners are hove simultaneously, the hook travels between two fixed points; by controlling the speed of each runner, the stevedore guides the lift from hatch to quay or vice versa. The union-purchase system is fast for repetitive small lifts but is limited to loads below approximately 5 tonnes and is sensitive to wind.

Single-swinging derricks - where one derrick has a powered swivel at the heel and travels in arc between the hold and the quay - are more flexible and can handle heavier loads. Typical derrick safe working loads (SWL) on a conventional 10,000 to 15,000 dwt vessel are 5 to 15 tonnes; jumbo derricks may reach 50 to 100 tonnes. The Stulcken derrick, distinctive for its bipod mast and the ability to slew through a wide arc without re-rigging, was capable of lifting 650 tonnes and was widely specified on the heavy-lift vessels of the 1950s through 1980s. Modern purpose-built HLVs have replaced the Stulcken with hydraulic pedestal cranes.

Deck cranes

Contemporary MPVs and post-1990 general cargo vessels almost universally fit slewing pedestal cranes rather than derricks. A crane of 30 to 60 tonnes SWL can serve a hatch alone or be combined with a second crane in tandem to double the lifting capacity. The Crane Tipping Moment - SWL vs Radius calculator and Crane Dynamic Factor (DNV-ST-0378) calculator are directly applicable to the safe working load and dynamic load assessment of such cranes. The dynamic factor, which increases the static load to account for vessel motion and hook-block dynamics, is normally in the range 1.1 to 1.3 for marine cranes and must be incorporated in stability assessments during heavy-lift operations.

Self-geared operation

The concept of a “geared” vessel - one carrying its own cargo-handling equipment - is central to the general cargo ship’s commercial proposition. Geared operation allows the vessel to call at ports without shore cranes or with cranes whose capacity is insufficient for the cargo. For project cargo operators trading to West African ports, Pacific island terminals, or construction sites, gear independence is often a primary charterer requirement. It distinguishes general cargo ships from “gearless” bulk carriers and container vessels, which depend on shore-based equipment.

Gear maintenance is a significant cost and operational consideration. Pedestal cranes require annual surveys by a competent person and periodic certification by a classification society-recognised inspection body under the Lifting Operations and Lifting Equipment Regulations or equivalent national frameworks. The safe working load marked on each crane applies at a specific radius; as the radius increases, the permissible load decreases in accordance with a rated-capacity curve supplied by the crane manufacturer. Crane operators must consult this curve for every heavy lift. The Crane Tipping Moment - SWL vs Radius calculator implements this relationship for planning purposes.

Cargo types and stowage practice

Break-bulk cargo

Break-bulk cargo is goods transported as individual units - bags, crates, bales, barrels, rolls, drums, pipes, or timber bundles - rather than consolidated into containers or loaded in bulk. A single consignment of bagged cement may consist of 2,000 bags each weighing 50 kg, each handled individually during loading and discharge. Break-bulk stowage is labour-intensive: stevedores work the hold, positioning bags in a block stow that maximises use of available space while maintaining stability and accessibility. The weight distribution of break-bulk cargoes must be checked against the vessel’s metacentric height to ensure adequate initial stability; the Metacentric Height (GM) calculator and the Trim from Loading Centroid calculator support these calculations. The Free Surface Correction calculator is relevant when slack ballast or fuel tanks are present alongside a deep break-bulk intake.

Palletised cargo

Palletisation converts break-bulk into unitised cargo: goods are stacked onto ISO pallets (1,200 × 1,000 mm standard European, 1,219 × 1,016 mm for the North American GMA pallet) and stretch-wrapped or banded as a single unit. A forklift can handle a standard pallet of up to 1,500 kg as a single lift, reducing gang sizes and port time compared with bag-by-bag handling. MPVs designed for palletised trades fit tween-decks with clearance heights of at least 2.7 m (to allow forklift mast extension above a loaded pallet) and tank-tops with smooth plating to permit forklift access. The IMSBC Loading Density Constraint calculator applies where bulk commodities are stowed in combination with unitised cargo on shared cargo spaces.

Timber

Timber cargo presents unique stowage and stability challenges. Logs, sawn timber, and bundled lumber are carried in holds and on the open deck in deck cargo packages. Deck timber reduces freeboard, alters the vessel’s centre of gravity, and changes the open area exposed to waves and wind. The SOLAS/ICLL provisions for timber load lines permit a reduced summer freeboard for vessels specially fitted for timber deck cargo, in recognition of the buoyancy contribution of the timber. However, the same deck timber absorbs water as the voyage progresses, increasing its weight and reducing the effective freeboard. Shipmaster’s stability instruments must account for water absorption, and the Fresh Water Allowance calculator assists in computing the adjustment when a timber-laden vessel transits between salt and fresh water. The load-line article covers the ICLL framework in detail.

Heavy-lift and project cargo

Project cargo is the commercial term for consignments that do not fit standard logistics: items too heavy, too long, too wide, or too tall to move in containers and requiring custom engineering for each transport leg. Common project cargo categories include:

Power generation equipment: gas turbines (typically 50 to 600 tonnes), steam turbines, boilers, large transformers (60 to 800 tonnes per unit), switchgear housings.
Offshore equipment: subsea manifolds, wellheads, umbilical reels, production modules, flare towers.
Construction equipment: tower cranes (disassembled), crawler cranes, tunnel boring machine segments, precast concrete bridge beams.
Renewable energy components: wind turbine nacelles (up to 500 tonnes), monopile foundations (1,000 to 1,600 tonnes per unit), transition pieces, blades (55 to 110 m long), offshore substation topsides.
Marine cargo: yachts and motor vessels, small coastal ships, modular accommodation units.

The stowage and securing of heavy-lift cargo involves engineering calculations for tank-top bearing pressure, crane radius and dynamic load, skidding loads, sea-fastening weld design, and stability during the lift sequence. The Crane Tipping Moment calculator and the Offshore Topside Installation Lift calculator address elements of this work.

Containerised cargo on MPVs

An MPV designed for container carriage fits cellular guides in its holds that accept 20-foot equivalent units (TEU) and 40-foot containers. Hold capacity is measured in TEU; a typical 12,000 dwt MPV may carry 400 to 600 TEU, compared with several thousand TEU on a purpose-built container ship of similar length. The practical advantage is not slot count but flexibility: an MPV can fill vacant container slots with bagged or palletised cargo stowed on wooden dunnage, can carry out-of-gauge units on the hatch covers, and can continue to an alternate port if the original port lacks container cranes. The Container Lashing - Twist-Lock Load calculator applies where containers are stowed in non-cellular positions with corner castings relying on twist-locks rather than dedicated cell guide rails.

Bulk cargo in general cargo holds

General cargo ships fitted with self-trimming bottom-hopper tanktops can occasionally carry minor bulk consignments - grain, fertiliser in bulk, salt, sugar - in their lower holds when a full container or break-bulk cargo is not available. Carriage of grain in bulk requires compliance with the IMO International Grain Code (Resolution MSC.23(59)), which limits the heeling moment of unsupported grain surfaces. The Grain Heel calculator performs the overstowing correction. Bulk carriage in general cargo vessels is limited by the absence of mechanical grabs and purpose-built self-discharging equipment, which makes discharge more expensive than from a bulk carrier.

Cargo securing

CSS Code

The Code of Safe Practice for Cargo Stowage and Securing (CSS Code), adopted by the IMO as MSC/Circ.385 and subsequently updated by MSC.1/Circ.1352 and supplemented by MSC.1/Circ.1353, provides the international framework for cargo securing on general dry cargo ships. The CSS Code specifies the acceleration forces that cargo must resist in terms of the ship’s length, service area, and the stowage position. It defines the balance of gravity forces, friction, and applied lashings that holds a cargo unit in place, and it requires each vessel to carry a ship-specific Cargo Securing Manual (CSM) approved by the flag administration and the vessel’s classification society.

The cargo securing manual article describes the CSM requirements in detail. For general cargo ships, the CSM typically specifies the SWL of each lashing point, the maximum lashing angle, the friction coefficient assumed for various cargo/dunnage combinations, and the number and arrangement of lashings required for each cargo category. The Ro-Ro Lashing - Trailer Holddown calculator applies CSS Code methodology to wheeled cargo; the Container Lashing calculator extends the same method to container units.

IMDG Code

Dangerous goods in packaged form - goods classified under the International Maritime Dangerous Goods Code - travel on general cargo ships in far greater variety and quantity than on container vessels, simply because the general cargo ship calls at smaller ports where no hazardous-cargo container berths exist. The IMDG Code requires segregation by hazard class: flammable liquids must be separated from oxidisers, toxic materials from foodstuffs, and so on. A general cargo ship’s cargo plan must demonstrate that IMDG Code segregation requirements are met across all holds and tween-decks. Distinction must be drawn between the IMDG Code (packaged dangerous goods), the IMSBC Code (solid bulk cargoes), and the IBC Code (bulk liquid chemicals in tanks), all of which may apply simultaneously to different parcels aboard the same vessel.

Sea fastening and securing plans for project cargo

Heavy-lift and project cargo requires individual engineering of the securing arrangement. The sea fastening for a 300-tonne transformer is typically welded directly to the ship’s deck structure, calculated to resist the combined effect of ship motion accelerations (longitudinal, transverse, and vertical) specified in the applicable classification society rule or the applicable ship-motion calculation method (commonly DNV-ST-N001 for offshore work, or classification society-derived accelerations for normal voyage conditions). The cargo stowage and securing plan for a project cargo voyage is a formal engineering document submitted to the vessel’s classification society for approval before loading.

Sea-fastening calculations account for the weight and centre of gravity of the cargo item, the metacentric height of the vessel at the loaded departure and intermediate conditions, the roll period, and the transit route’s likely sea state. Classification societies use different acceleration tables: DNV, Bureau Veritas, and Lloyd’s Register each publish their own tables, which may differ by up to 15% for the same route and ship length. The sea-fastening structure is typically fabricated in steel plate and sections, welded to deck pad-eyes or to a grillage frame, and removed at the discharge port by the ship’s crew or the local stevedore. Reusable frames are stored in a dedicated space aboard HLVs that carry the same project cargo type repeatedly.

Cargo stability during a crane lift deserves separate attention. When the crane is picking a load from the hold, the added weight at the end of the jib creates a heeling moment that must be counteracted by ballast water transfer. The sequence of ballasting operations - transferring water from the high side to the low side as the crane luff increases - is calculated in advance and entered in the stability instrument. Classification societies require that the GM at any stage of the lift remains positive with an adequate margin.

Regulatory framework

SOLAS and ICLL

General cargo ships are subject to the full requirements of the SOLAS Convention, including Chapter II-1 (construction and subdivision), Chapter II-2 (fire protection), Chapter III (lifesaving appliances), Chapter IV (radio), and Chapter VI (carriage of cargo). SOLAS Chapter VI Part A prescribes general requirements for cargo loading, stowage, and securing, and Chapter VI Part B applies specifically to grain. Chapter VII covers dangerous goods and cross-references the IMDG Code.

The International Convention on Load Lines 1966 (ICLL) governs freeboard assignment - the distance between the waterline and the deck edge. General cargo ships are assigned a summer load line corresponding to their permitted deadweight in summer sea areas, adjusted for seasonal zones and the fresh water allowance. The load-line article describes the ICLL zone assignments and the calculation of the fresh water allowance in detail.

MARPOL

The MARPOL Convention applies to general cargo ships primarily through:

Annex I (oil): requirements for the prevention of pollution by oil from machinery spaces, with oily water separators and oil record books mandatory above 400 gross tonnes.
Annex V (garbage): disposal of garbage at sea is prohibited or strictly controlled; garbage management plans and garbage record books are required.
Annex VI (air pollution): limits on sulphur content of fuel oil (0.5% global cap since 2020, 0.1% in Emission Control Areas under the IMO 2020 sulphur cap rules) and on nitrogen oxide emissions from main engines, relevant to the marine diesel engine type fitted.

STCW

Officers and ratings on general cargo ships are certificated under the STCW Convention. The cargo officer function - responsibility for cargo planning, stability calculations, and securing - is part of the STCW officer of the watch and chief officer competency framework, covered in the Table A-II/1 and A-II/2 training matrices. General cargo and MPV operations require competency in stability assessment and cargo securing that is more complex than for single-cargo vessels because the mixed nature of the cargo introduces more variables in the loading calculation.

EEDI and EEXI for general cargo ships

The IMO energy efficiency framework under MARPOL Annex VI applies to new and existing general cargo ships above 400 gross tonnes. The Energy Efficiency Design Index (EEDI), required for ships contracted on or after 1 January 2013, specifies a minimum efficiency level expressed in grams of CO2 per tonne-mile. For the “General cargo ships” category, the EEDI reference line parameters and phase reduction factors are defined in Regulation 21 of MARPOL Annex VI and follow the standard formula: attained EEDI = (CO2 from main and auxiliary engines at 75% MCR) / (reference capacity × reference speed). The EEDI Attained calculator and EEXI Attained calculator implement these calculations for general cargo ship parameters.

The Energy Efficiency Existing Ship Index (EEXI) extended efficiency requirements to existing vessels from 1 November 2022. General cargo ships above 400 gross tonnes that cannot meet the required EEXI value through technical measures must install an engine power limitation (EPL) device or shaft power limitation (ShaPoLi). The Carbon Intensity Indicator (CII) annual rating adds an operational dimension: actual CO2 per tonne-mile must improve by 2% per year from 2023 to 2030. The CII Attained calculator computes the annual CII value for vessels including general cargo ships. The what-is-cii, what-is-eedi, and what-is-eexi articles cover the policy context for these indices.

ISM Code and classification

General cargo ships in international service are managed under the ISM Code, with the Document of Compliance (DoC) issued to the company and the Safety Management Certificate (SMC) issued to each vessel. Classification societies approve hull scantlings, machinery, and cargo handling equipment and issue load line certificates. The major classification societies active in the general cargo and MPV segment include Lloyd’s Register, Bureau Veritas, DNV, Nippon Kaiji Kyokai (ClassNK), and Korean Register.

IMO DCS and EU MRV

General cargo ships above 5,000 gross tonnes are subject to both the IMO Data Collection System for fuel oil consumption (IMO DCS, implemented under MARPOL Annex VI Regulation 27 from 1 January 2019) and the EU Monitoring, Reporting and Verification Regulation (EU MRV, Regulation (EU) 2015/757, applicable from 1 January 2018). Under IMO DCS, annual fuel oil consumption, distance travelled, and hours underway are reported to the flag administration and recorded in the Ship Energy Efficiency Management Plan (SEEMP). Under EU MRV, CO2 emissions per voyage are reported to an accredited verifier and submitted to the European Maritime Safety Agency (EMSA) platform. The imo-dcs-vs-eu-mrv article explains the two parallel regimes and their differences. General cargo ships below 5,000 gross tonnes - which includes a significant fraction of the MPV fleet - are exempt from both IMO DCS and EU MRV but still subject to MARPOL Annex VI fuel oil sulphur requirements.

Commercial operation and chartering

Voyage and time charter

General cargo ships and MPVs are chartered under both voyage and time charter arrangements. Voyage charters for general cargo use the GENCON form (BIMCO Gencon 94 or Gencon 2022), which provides for freight payable per tonne of cargo delivered. Project and heavy-lift voyages often use BIMCO HEAVYCON 2007, a form designed for single-voyage transport of heavy and oversized cargo that specifies the cargo description, lifting specifications, lashing schedule, and port/terminal conditions as schedule annexes. The Time-Charter Equivalent (TCE) - Voyage calculator converts voyage charter results to a time-charter equivalent for comparison with time-charter offers. General average, relevant to any voyage involving significant cargo damage or salvage, is calculated using the York-Antwerp Rules; the General Average - York-Antwerp Contribution calculator covers that calculation.

Rate indices

The general cargo and MPV segment does not have a dedicated Baltic Exchange index equivalent to the Baltic Dry Index. Project cargo freight rates are negotiated bilaterally between operator and charterer for each shipment. The Sea Cargo Charter Alignment calculator is relevant for operators aligning fleet chartering policies with the Sea Cargo Charter initiative.

Principal operators

BBC Chartering, the commercial arm of the Briese group based in Leer, Germany, is the world’s largest MPV operator measured by fleet capacity, deploying over 130 vessels of 3,000 to 25,000 dwt. Its BBC carrier series and Combi Dock vessels operate across Atlantic, Pacific, and Indian Ocean routes carrying project and heavy cargo. AAL Shipping (Ahrenkiel Allgemeine Linienschiffahrt) operates a fleet of large MPVs on Asia-Australia-Americas services. Chipolbrok operates on fixed-liner routes between China, Europe, and the Americas.

In the heavy-lift specialist segment, SAL Heavy Lift (part of the Harren Group, Bremen) operates vessels of 8,000 to 13,000 dwt fitted with 2,000-tonne combined lifting capacity. BigLift Shipping (Amsterdam) operates the Happy series and Biga vessels with 900-tonne combined lifting capacity. Jumbo Shipping (Rotterdam) operates vessels including the Stella and Fairmaster series, combining 3,000-tonne combined lifting capacity with offshore installation capability. dship Carriers (Hamburg) and Hansa Heavy Lift operate MPV and HLV tonnage on the spot and project markets.

Vessel valuation and lay-up

General cargo ships command lower market values than equivalent-deadweight bulk carriers or tankers on account of their more complex operation and smaller cargo flow per voyage. The Vessel Fair Market Value calculator provides indicative valuations based on vessel age, size, and recent market transactions. Lay-up economics for MPVs are assessed using the Vessel Lay-Up Cost calculator, relevant in soft market periods such as the post-2008 trough in project cargo volumes.

Bill of lading and documentation

General cargo voyages produce more complex documentation than bulk carrier voyages because individual consignments from multiple shippers are loaded at the same port or across multiple ports. Each parcel is covered by a separate bill of lading (B/L) that serves as a receipt for the goods, evidence of the contract of carriage, and document of title. A single general cargo ship may carry 50 to 500 separate bills of lading on a port-to-port voyage, each requiring individual freight calculation, cargo description, and port delivery arrangements. On project cargo voyages, the B/L is usually replaced by a Sea Waybill or a single negotiable B/L for the entire cargo, and the HEAVYCON charter party governs the rights and obligations of the parties.

Deck cargo - timber, oversized items lashed to the weather deck, or containers carried on hatch covers - must be noted as such on the B/L to limit the carrier’s liability for weather damage. A clean B/L for deck cargo may reduce the bill of lading’s negotiability as a document of title in some jurisdictions. The distinction between clean and claused bills of lading is fundamental to the trade finance instruments (letters of credit) used to pay for cargo in many general cargo trades.

Special categories and derivatives

Wind turbine installation vessel

The offshore wind industry created demand from the mid-2000s for specialised vessels capable of installing wind turbine foundations, towers, nacelles, and blades at sea. Early installations used purpose-converted MPVs and HLVs for component transport. The dedicated wind turbine installation vessel (WTIV) that emerged is an HLV derivative - typically a jack-up vessel with four to eight legs that plants itself on the seabed during installation - combining heavy lifting (800 to 2,000 tonnes capacity) with leg-supported platform stability that eliminates vessel motion during the lift. WTIVs such as the Heerema Sleipnir (semi-submersible crane vessel, 10,000-tonne capacity) and the Cadeler series represent a divergence from the general cargo ship type, but the operational and regulatory heritage is common.

Conventional semi-submersible heavy-lift vessels such as the Dockwise Vanguard, capable of submerging its deck to float and transport entire floating structures, represent the large end of the HLV spectrum. The Vanguard carried the Prelude FLNG hull sections and similar oversized structures for Heerema and Shell during the 2010s.

Yacht carrier

A small number of MPVs and HLVs operate as specialist yacht carriers, loading luxury motor yachts and sailing yachts of 15 to 90 m length as deck cargo for transatlantic and transpacific delivery passages. The principal operators are Sevenstar Yacht Transport (part of Spliethoff) and Yacht Path International. The logistics involve positioning the yacht on deck using the ship’s cranes, constructing a custom cradle, and sea-fastening to the deck. Insurance requirements under marine cargo policies and classification requirements for the yacht as cargo are addressed in cooperation with the owner’s P&I club.

Lo-lo and ro-ro general cargo variants

Lo-lo (lift on, lift off) general cargo vessels handle cargo exclusively by crane or derrick - the standard arrangement. Ro-ro (roll on, roll off) cargo is driven or rolled aboard via a stern or side ramp, eliminating the need for a hoist. Some MPVs combine lo-lo and ro-ro capability: a stern ramp provides access for wheeled and tracked project cargo that cannot be lifted safely, while deck cranes handle conventional cargo. The Ro-Ro Ramp Angle calculator and Ro-Ro Lashing - Trailer Holddown calculator support planning for the ro-ro element of such operations. The ro-ro vessel article covers dedicated ro-ro and PCTC vessel types.

General cargo ships in liner services

West Africa remains one of the strongest markets for conventional general cargo liner service. The trade structure of many West African countries - importing a wide variety of consumer goods, manufactured items, construction materials, and project cargo in small consignments - favours the MPV over the fully cellular container ship. Operators including Grimaldi Lines, DAL (Deutsche Afrika-Linien), and CMA CGM Africa run scheduled services combining ro-ro and lo-lo general cargo vessels. Pacific island services to Fiji, Samoa, Tonga, Papua New Guinea, and the Solomon Islands similarly rely on geared MPVs capable of operating at ports with minimal shore infrastructure.

Latin American coastal services, particularly on the west coast between Ecuador, Peru, and Chile, and on the east coast serving the River Plate and the Amazon system tributaries, continue to use general cargo ships for project cargo and breakbulk commodities where container services are insufficient.

Stability and loading considerations

A general cargo ship’s loading computer must model a wider range of cargo configurations than a bulk carrier or container vessel. A typical voyage intake may combine high-density machinery on the tank-top (raising the centre of gravity of the lower parcel), timber on deck (raising the overall centre of gravity, adding heeling moment if asymmetrically stowed), containers in cellular holds (governed by stack weight limits), and a heavy-lift unit on the weather deck (creating a transverse heeling moment during the crane lift sequence). Stability must be demonstrated at all intermediate loading stages, not only at departure and arrival.

The metacentric height is the primary initial stability parameter. For general cargo ships, the minimum GM requirements under the 2008 IS Code (Resolution MSC.267(85)) applicable to cargo ships are 0.15 m, though in practice operators maintain larger values to provide a margin for cargo shift and free surface effects in slack tanks. The free surface effect is particularly significant when ballast tanks are partially filled during cargo operations, as is common in MPV heavy-lift voyages where ballast transfer compensates for the crane overhang moment.

The intact stability article discusses the IS Code stability criteria applicable to general cargo ships. For vessel structural loading, the trim and list article covers the calculation of trim and the conditions under which list becomes a safety concern.

Cargo plan and loading sequence

The cargo plan for a multi-port general cargo voyage is prepared by the chief officer before the first loading port and revised after each port. It shows every cargo parcel with its hold, tier or deck position, gross weight, and stowage factor. The loading sequence is optimised to ensure: the vessel does not exceed the maximum hold or tween-deck floor load at any stage; the trim and list remain within limits throughout; IMDG Code segregation requirements are met between ports; and cargo for the last discharge port is stowed deepest (last on, first off). Software tools such as MACS3, PortLog, and classification society-supplied stability programs assist officers in solving these simultaneous constraints. The output from a certified stability program is the loading condition printout accepted by the port state control officer as evidence of compliance with SOLAS Chapter II-1.

Grain stability and shift considerations

Even when a general cargo vessel is not carrying grain, the stability criteria developed for grain carriage are instructive for any cargo that can shift. CSS Code Chapter 1 uses a calculation of “advanced stability” that considers the residual stability area above a heeled condition; the same approach is applied to cargo that may shift under roll. For break-bulk stow where individual bags or packages are not secured against athwartships movement, the cargo officer must assess whether the stow is stable against the anticipated roll period and amplitude and whether additional lashing or dunnage is required to prevent shift. Shift of a heavy-lift item secured on deck represents the most severe stability hazard on an MPV; the failure of a sea-fastening weld under storm conditions could be catastrophic. This is why classification society approval of the securing plan is mandatory before sailing.

Environmental performance

Propulsion plant

General cargo ships and MPVs are typically propelled by a single medium-speed four-stroke or slow-speed two-stroke diesel engine driving a fixed-pitch or controllable-pitch propeller through a reduction gearbox or directly. The marine diesel engine article covers the distinction between main engine types. Medium-speed four-stroke engines in the range 4,000 to 9,000 kW are common on MPVs because they allow a more compact engine room arrangement and are compatible with the controllable-pitch propeller systems that offer full manoeuvring flexibility without a separate bow thruster in many port approaches. Larger general cargo ships and HLVs may carry a slow-speed two-stroke engine of 6,000 to 15,000 kW. Auxiliary power is provided by two or three diesel generator sets; on heavy-lift vessels the crane power demand during operations may necessitate a dedicated crane generator or an oversize auxiliary set. The specific fuel oil consumption article explains the SFOC parameter used in EEDI and EEXI calculations.

Bow thrusters are fitted on most MPVs and HLVs to provide independent lateral thrust for port manoeuvring without tug assistance. The bow thruster and stern thruster article covers the hydrodynamics of transverse thrusters, which are important for HLVs that must maintain precise position during a crane lift at anchor or at a jetty.

Fuel consumption and CO2

General cargo ships and MPVs are less fuel-efficient per tonne-mile than bulk carriers or large container vessels, primarily because their smaller size prevents them from exploiting economies of scale in hull resistance and propulsion. A 12,000 dwt MPV at service speed of 15 knots consumes approximately 25 to 35 tonnes per day of heavy fuel oil or marine gas oil. Slow steaming, reducing service speed from 15 to 12 knots, can cut fuel consumption and CO2 by 35 to 40% on a per-voyage basis, consistent with the cubic law of propulsive power with speed. The Voyage Fuel and CO2 calculator and Slow Steaming Savings calculator quantify these economics. The slow steaming and CII article discusses the interaction between speed reduction and CII rating improvement.

Fuel types

Most MPVs and general cargo ships operate on heavy fuel oil or marine gas oil. The 0.5% sulphur global cap under MARPOL Annex VI that came into force on 1 January 2020 prompted a shift by much of the general cargo fleet to very low sulphur fuel oil (VLSFO) or marine gas oil. LNG as a bunker fuel is rare in this segment because the relatively short operating life of many vessels and the limited return from newbuilding investment makes LNG bunker retrofit difficult to justify. Methanol and ammonia fuels remain at the demonstration phase for this vessel type. The FuelEU Maritime regulation’s greenhouse gas intensity requirements from 2025 onward will apply to general cargo ships above 5,000 gross tonnes on voyages calling at EU ports.

Exhaust gas cleaning

Exhaust gas cleaning systems (scrubbers) have been fitted to a minority of general cargo vessels, primarily on the larger MPV and HLV units where the economics of scrubber payback are more favourable. The exhaust-gas-cleaning-system article describes open-loop and closed-loop scrubber configurations. The EU ETS for shipping imposes a carbon cost on voyages calling at EU ports above 5,000 gross tonnes from 2024, affecting the commercial calculations for general cargo ships on Europe trades.

Fleet statistics and market position

The general cargo and multipurpose fleet comprises approximately 20,000 vessels above 1,000 dwt, with around 3,500 vessels exceeding 10,000 dwt, according to the vessel register compilations maintained by classification societies and shipping databases. The fleet’s average age is high relative to specialised vessel types - many active MPVs were built in the 1990s and early 2000s, and some tween-deckers of 1970s and 1980s vintage remain in service on niche routes. Newbuilding activity is modest; most ordering has been concentrated in specialist HLV and project carrier segments. The ShipCalculators.com calculator catalogue covers the full range of general cargo and MPV technical and commercial tools for this fleet.

A persistent structural characteristic of the general cargo segment is the prevalence of small owner-operators and the high proportion of single-vessel or two-to-three-vessel companies. The economics of breakbulk and project cargo favour niche specialists over large fleets: each shipment requires individual planning, pricing, and engineering work that rewards expertise over scale. Major container operators such as Maersk, MSC, and CMA CGM have found the general cargo sub-segment uneconomic at corporate scale, confining their exposure to the containerised portion carried on MPVs or to dedicated ro-ro vessels.

Port state control inspections under the Paris MOU, Tokyo MOU, and other regional arrangements apply fully to general cargo ships; this vessel type historically appears disproportionately in deficiency statistics, reflecting the age profile of the fleet and the small company structure of many owners. The port-state-control article covers inspection procedures and common deficiency categories.

Recycling and end of life

General cargo ships at end of life are subject to the Hong Kong Convention on the safe and environmentally sound recycling of ships (adopted 2009, entry into force contingent on ratification thresholds). Vessels flagged to states that have ratified the Convention, or calling at ports of states that apply its provisions, must carry an Inventory of Hazardous Materials and be dismantled at a yard approved under the Convention. Many general cargo ships are recycled at South Asian cash sale yards in Bangladesh, India, and Pakistan. The residual scrap value of a general cargo ship represents a significant fraction of its market value when the vessel approaches 25 to 30 years of age, and scrapping economics interact with the market decision on whether to continue operation or sell for demolition. The Vessel Scrap Price calculator provides an indicative scrap valuation.

References

IMO, Code of Safe Practice for Cargo Stowage and Securing (CSS Code), MSC.1/Circ.1352, 2010, and amending circular MSC.1/Circ.1353, 2010.
IMO, International Maritime Dangerous Goods (IMDG) Code, incorporating Amendment 41-22, 2022.
IMO, International Convention on Load Lines 1966, as amended (ICLL 1966/1988 Protocol).
IMO, MARPOL Consolidated Edition 2022, Annex VI, Regulations 20-23 (EEDI) and 24-26 (EEXI/CII).
IMO, Resolution MSC.267(85), Adoption of the International Code on Intact Stability, 2008 (2008 IS Code), 4 December 2008.
IMO, International Code for the Safe Carriage of Grain in Bulk (International Grain Code), Resolution MSC.23(59), 1992.
IACS, Unified Requirement S26: Strength and securing of hatch covers of dry cargo ships, Rev.6, 2020.
IACS, Unified Requirement S21A: Hatch cover design pressures, Rev.6, 2015.
IACS, Unified Requirement S34: Strength of end hatch covers exposed to wave impact, 2013.
BIMCO, HEAVYCON 2007 - Standard Contract for Heavy and Voluminous Cargoes, 2007.
Austin and Pickersgill Ltd, SD-14 General Cargo Vessel - Design History, Sunderland, 1967-1981 (company records, widely cited in Osborne, The SD14, 2003).
Eyres, D.J. and Bruce, G.J., Ship Stability for Masters and Mates, 7th edition, Butterworth-Heinemann, 2012.
Barras, C.B., Ship Stability for Masters and Mates, 7th edition, Elsevier, 2012.
Molland, A.F. (ed.), The Maritime Engineering Reference Book, Butterworth-Heinemann, 2008.
UNCTAD, Review of Maritime Transport, annual series, United Nations, Geneva.

External links

IMO CSS Code (MSC.1/Circ.1352) - official IMO page for cargo stowage and securing
BIMCO HEAVYCON 2007 - BIMCO standard heavy-lift voyage charter form
BBC Chartering fleet - Briese group MPV operator
BigLift Shipping - Amsterdam-based HLV operator
Jumbo Shipping - Rotterdam-based HLV operator
SAL Heavy Lift - Harren Group HLV operator