Cargo Terms and Definitions
The following terminology is reproduced hereunder, courtesy of Cargo Work For Maritime Operations – 7th Edition, by David J. House .
Air draught – means the vertical distance from the surface of the water to the highest point of the ship’s mast or aerial.
Bale space capacity – is that cubic capacity of a cargo space when the breadth is measured from the inside of the cargo battens (spar ceiling) and the measured depth is from the wood tank top ceiling to the underside of the deck beams. The length is measured from the inside of the fore and aft bulkhead stiffeners.
Broken stowage – is defined as that space between packages which remains unfilled. The percentage that has to be allowed varies with the type of cargo and with the shape of the ship’s hold. It is greatest when large cases are stowed in an end hold or at the turn of a bilge.
Cargo information – means appropriate information relevant to the cargo and its stowage and securing which should specify, in particular, the precautions necessary for the safe carriage of that cargo by sea.
Cargo plan – a ship’s plan which shows the distribution of all cargo parcels stowed on board the vessel for the voyage. Each entry onto the plan would detail the quantity, the weight and the port of discharge. The plan is constructed by the Ship’s Cargo Officer and would effectively show special loads such as heavy-lifts, hazardous cargoes, and valuable cargo, in addition to all other commodities being shipped.
Cargo runner – a general term used to describe the cargo lifting wire used on a derrick. It may be found rove as a ‘single whip’ or doubled up into a ‘gun tackle’ (two single blocks) or set into a multi-sheave lifting purchase. It is part of the derricks ‘running rigging’ passing over at least two sheaves set in the head block and the heel block, prior to being led to the barrel of the winch. Normal size is usually 24 mm and its construction is flexible steel wire rope (FSWR) of 6 x 24 wires per strand (wps).
Cargo securing manual – a manual that is pertinent to an individual ship, and which will show the lashing points and details of the securing of relevant cargoes carried by the vessel. It is a ship’s reference which specifies the on-board securing arrangements for cargo units, including vehicles and containers, and other entities. The securing examples are based on the transverse, longitudinal and vertical forces which may arise during adverse weather conditions at sea. The manual is drawn up to the standard contained in Maritime Safety Committee (MSC) Circular of the Organization, MSC/Circ. 745.
Cargo ship – defined as any ship which is not a ‘Passenger Ship’, troop ship, pleasure vessel or fishing boat.
Cargo spaces – (e.g. cargo hold) – means all enclosed spaces which are appropriate for the transport of cargo to be discharged from the ship. Space available for cargo may be expressed by either the vessel’s deadweight or her cubic capacity in either bale or grain space terms.
Cargo unit – includes a cargo transport unit and means wheeled cargo, vehicles, containers, flat pallet, portable tank packaged unit or any other cargo and loading equipment or any part thereof, which belongs to the ship and which is not fixed to the ship.
Centre of buoyancy – is defined as the centre of the underwater volume; that point through which all the forces due to buoyancy are considered to act.
Centre of gravity (C of G) – is defined as that point through which all the forces due to gravity are considered to act. Each cargo load will have its own C of G.
Dangerous goods – are defined as such in the UK Merchant Shipping (Dangerous Goods and Marine Pollutants) Regulations 1990.
Deadweight – means the difference in tonnes between the displacement of a ship at the summer load waterline in water of specific gravity of 1025, and the lightweight of the ship.
Deadweight cargo – is cargo on which freight is usually charged on its weight. While no hard and fast rules are in force, cargo stowing at less than 1.2m3/tonne (40 ft3/tonne) is likely to be rated as deadweight cargo.
Dunnage – an expression used to describe timber boards which can be laid singularly or in double pattern under cargo parcels to keep the surface of the cargo off the steel deck plate. Its purpose is to provide air space around the cargo and so prevent ‘cargo sweat’. Heavy-lift cargoes would normally employ heavy timber bearers to spread the load and dunnage would normally be used for lighter-load cargoes.
Flemish Eye – a name given to a Reduced Eye made of three strands (not six), spliced into the end of a cargo runner which is secured to the barrel of a winch (alternative names are Spanish Eye, or Reduced Eye).
Flemish hook – a large hook, often used in conjunction with the lower purchase block in the rigging of a heavy-lift derrick. The hook can be opened to accommodate the load slings and then bolt locked.
Floodable length – the maximum length of a compartment that can be flooded to bring a damaged vessel to float at a waterline which is tangential to the margin line. Note: In determining this length account must be taken of the permeability of the compartment.
Freight – the term used to express the monetary charge which is levied for the carriage of the cargo.
Gooseneck – the bearing and swivel fitment, found at the heel of a derrick which allows the derrick to slew from port to starboard, and luff up and down when in operation.
Grain capacity – is that cubic capacity of a cargo space when the length, breadth and depth are measured from the inside of the ship’s shell plating, all allowances being made for the volume occupied by frames and beams.
Gross tonnage – is defined by the measurement of the total internal capacity of the ship. GT being determined by the formula: GT= KiV where:
Ki = 0.2 + 0.02 Log 10V
V = Total volume of all enclosed spaces in cubic metres
Hallen universal swinging derrick – a single swinging derrick with a lifting capacity of up to about 100 tonnes safe working load (SWL) The original design employed a ‘D’ frame, to segregate the leads of the combined slewing and topping lift guys. The more modern design incorporates ‘outriggers’ for the same purpose.
Hounds Band – a lugged steel band that straps around a ‘mast’. It is used to shackle on shrouds and stays. It is also employed to secure ‘Preventer Backstays’ when a heavy derrick is being deployed in order to provide additional strength to the mast structure when making the heavy lift.
Load density plan – a ships plan which indicates the deck load capacity of cargo space areas of the ship. The Ship’s Chief Officer would consult this plan to ensure that the space is not being overloaded by very dense, heavy cargoes.
Long tonne – a unit of mass weight, equal to 2240lb (tonne).
Luffing – a term which denotes the movement of a crane jib or derrick boom to move up or down, i.e. ‘luff up’ or ‘luff down’.
Luffing derrick – a conventional single swinging derrick rigged in such a manner that permits the derrick head to be raised and lowered to establish any line of plumb, as opposed to static rigged derricks, as with a ‘Union Purchase Rig’.
Measurement cargo – is cargo on which freight is usually charged on the volume occupied by the cargo. Such cargo is usually light and bulky stowing at more than 1.2m3 per tonne (40 cu. ft./tonne), but may also be heavy castings of an awkward shape where a lot of space is occupied.
Passenger Ship – a ship designed to carry more than12 passengers.
Permeability – in relation to a compartment space means the percentage of that space which lies below the margin line which can be occupied by water. Note: various formulae within the Ship Construction Regulations are used to determine the permeability of a particular compartment. Example values are spaces occupied by cargo or stores 60%, spaces employed for machinery 85%, passengers and crew spaces 95%.
Permissible length – of a compartment having its centre at any point in the ships length is determined by the product of the floodable length at that point and the factor of sub division of the vessel:
permissible length = floodable length x factor of subdivision.
Riding turn – an expression that describes a cross-turn of wire around a barrel of a winch, or stag horn. It is highly undesirable and could cause the load to jump or slip when in movement. The condition should be cleared as soon as possible.
Ring bolt – a deck ring or ‘pad eye’ often used in conjunction with a doubling plate or screw securing. It is employed to provide an anchor point for associated rigging around a derrick position.
Running rigging – a descriptive term used to describe wire or cordage ropes which pass around the sheave of a block (see also ‘Standing Rigging’). Where steel wire ropes are employed for running rigging they are of a flexible construction, examples include: 6 x 24 wps and 6x 36 wps.
Safe working load – an acceptable working tonnage used for a weight-bearing item of equipment. The marine industry uses a factor of one-sixth the breaking strain (BS) to establish the safe working value.
Safety tongue – a spring clip sealing device to cover the jaw of a lifting hook. It should be noted that these devices are not fool-proof and have been known to slip themselves unintentionally. The tongue is meant to replace the need of ‘mousing’ the hook, and is designed to serve the same purpose as a ‘mousing’.
Schooner guy – a bracing guy which joins the spider bands at the derrick heads of a ‘Union Purchase Rig’.
Sheer legs – a large lifting device employed extensively within the marine industry. It is constructed with a pair of inclined struts resembling a crane, although the action when working is similar to a craning activity. (Smaller versions of sheer legs were previously used within the marine industry on tankers to hoist pipelines on board or more commonly found in training establishments for training cadets in rigging applications.) The modern day sheer legs are now found on floating heavy-lift (crane) barges and employed for extreme lifting operations usually with ‘project cargoes’. it is interesting to note that a stunning example of sheer legs may be seen at the Birgo "Macina" (corruption of the Italian Macchina - or machine) in Malta. These sheer legs were originally constructed for use by the navy of the Order of St. John, also known as the Knights of Malta.
Shore – a term used to describe a support, given to decks, bulkheads or cargo. They are usually timber, but may be in the form of a metal stanchion, depending on the intended use (see tomming).
Slings – a term which describes the lifting strops to secure the load to be hoisted to the lift hook of the derrick or crane. Slings may be manufactured in steel wire rope, chains, rope or canvas.
Snatch block – a single sheave block, often employed to change the direction of lead, of a wire or rope. The block has a hinged clamp situated over the ‘swallow’ which allows the bight of a wire or rope to be set into the block without having to pull the end through.
Snotter – a length of steel wire with an eye in each end. Employed around loads as a lifting sling, with one eye passed through the other to tighten the wire around the load.
Speed crane – modern derrick design with multi-gear operation which operates on the principle of the single jib, point loading crane.
Spider band – a steel lugged strap found around the head of a derrick which the rigging, such as the topping lift and guys are shackled onto. The equivalent on a mast structure is known as a ‘Hounds Band’.
Spreader – a steel or wood batten which effectively spreads the wire sling arrangement wider apart when lifting a large area load. Use of such a spreader generally provides greater stability to the movement of the weight. Formerly referred to as a lifting beam.
Stabilizers – Steel outriders, often telescopic in design and fitted with spread feet, which are extended from the base unit of a shore-side mobile crane. Prior to taking the load the stabilizers are set to ensure that the load on the crane jib will not cause the crane to topple. (Not to be confused with ship stabilizers fitted to ships to reduce rolling actions of the vessel when at sea.)
Standing Rigging – a term used to describe fixed steel wire rope supports. Examples can be found in ship’s stays and shrouds. Construction of Standing Rigging is usually 6 x 6 wps.
Stowage factor – this is defined as that volume occupied by unit weight of cargo. Usually expressed as cubic metres per tonne (m3/tonnes) or cubic feet per tonne (ft3/tonne). It does not take account of any space which may be lost due to ‘broken stowage’. A representative list of stowage factors is provided at the end of this book.
Subdivision factor – the factor of subdivision varies inversely with the ship’s length, the number of passengers and the proportion of the underwater space used for passenger/crew and machinery space. In effect it is the factor of safety allowed in determining the maximum space of transverse watertight bulkheads, i.e. the permissible length.
Tomming off – an expression that describes the securing of cargo parcels by means of baulks of timber. These being secured against the cargo to prevent its movement if and when the vessel is in a seaway and experiencing heavy rolling or pitching motions (alternative term is ‘shore’).
Tonne – originated from the word ‘tun’ which was a term used to describe a wine cask or wine container, the capacity of which was stated as being 252 gallons as required by an Act of 1423, made by the English Parliament. It is synonymous that 252 gallons of wine equated to approximately 2240 lb, ‘1 tonne’ as we know it today.
Trunnion – a similar arrangement to the ‘gooseneck ’of a small derrick. The Trunnion is normally found on intermediate size derricks of 40 tonnes or over. They are usually manufactured in cast steel and allow freedom of movement from the lower heel position of the derrick.
Tumbler – a securing swivel connection found attached to the ‘Samson Post’ or ‘Mast Table’ to support the topping lift blocks of the span tackle.
‘U’ bolt – a bolt application which secures the reduced eye of a cargo runner to the barrel of a winch.
Union Plate – a triangular steel plate set with three eyelets used in ‘Union Rig’ to join the cargo runners and hook arrangement when a ‘triple swivel hook’ is not employed. It can also be used with a single span, topping lift derrick to couple the downhaul with the chain preventer and bull wire. Sometimes referred to as ‘Monkey Face Plate’.
Union Rig – Alt; Union Purchase Rig. A derrick rig which joins two single swinging derricks to work in ‘Union’ with cargo runners joined to a triple swivel hook arrangement known as a ‘Seattle Hook’ or ‘Union Hook’. The rig was previously known as ‘Yard and Stay’ and is a fast method of loading/discharging lighter parcels of cargo. Union Rig operates at approximately one-third of the SWL of the smallest derrick of the pair.
Velle Derrick – a moderate heavy-lift derrick that can be operated as a crane by a single operator. The derrick is constructed with a ‘T’ bridle piece at the head of the derrick which allows topping lift-wires to be secured to act in way of slewing guys and/or topping lift.
Walk back – an expression which signifies reversing the direction of a winch in order to allow the load to descend or the weight to come off the hoist wires.
Weather deck – means the uppermost complete deck exposed to the weather and the sea.
Wires per strand – an expression (abbreviated as "wps") which describes the type of construction of the strands of a steel wire rope.
Yard and Stay – alternative descriptive term for Union Purchase Rig.