Ships

Almost everything manufactured, packed into standard ISO containers: 20 ft, 40 ft, 40 ft high-cube, plus reefers for chilled and frozen cargo, tank containers for liquids, and flat racks and open tops for anything that will not fit in a box. Capacity is counted in TEU — twenty-foot equivalent units.

• Feeder Up to about 3,000 TEU. Short-sea and regional services feeding the main hubs.
• Feedermax Roughly 3,000–5,000 TEU, often geared with their own cranes.
• Panamax About 5,000 TEU — sized to the original Panama Canal locks, 32.3 m beam.
• Post-Panamax Too wide for the old locks; roughly 5,000–10,000 TEU.
• Neopanamax Sized to the 2016 Panama locks — up to about 14,000 TEU, 51.25 m beam.
• ULCV Ultra Large Container Vessel. 14,500 TEU and above, now reaching 24,000 TEU.

LARGEST IN SERVICE

~24,000 TEU

TYPICAL LOA

300–400 m

CREW

20–26

SERVICE SPEED

16–22 kn

Unrefined crude oil, loaded at a terminal or an offshore buoy and discharged at a refinery. Cargo is carried in uncoated segregated tanks with inert gas above it, and the ship is double-hulled throughout the cargo length.

• Panamax 60,000–80,000 dwt. Regional crude and dirty product trades.
• Aframax 80,000–120,000 dwt. Named for the old Average Freight Rate Assessment scale.
• Suezmax 120,000–200,000 dwt — the largest that can transit the Suez Canal loaded.
• VLCC Very Large Crude Carrier. 200,000–320,000 dwt, the workhorse of long-haul crude.
• ULCC Ultra Large Crude Carrier. Above 320,000 dwt; very few remain in service.

CARGO

Crude oil

TANK COATING

Uncoated

INERT GAS

Required

HULL

Double

Refined petroleum products — gasoline, diesel, jet fuel, naphtha — and on chemical tankers, everything from caustic soda and methanol to vegetable oils. Multiple grades travel at once in coated or stainless steel tanks, each with its own pump and line, and tanks are cleaned between most cargoes.

• Handysize 10,000–25,000 dwt. Short-sea and coastal distribution.
• MR Medium Range, 25,000–55,000 dwt. The most common clean product tanker.
• LR1 Long Range 1, 55,000–80,000 dwt.
• LR2 Long Range 2, 80,000–120,000 dwt, on the longest clean trades.
• IMO Type II Cargoes needing significant preventive measures; tank size and location restricted.
• IMO Type III Cargoes needing moderate containment — most clean petroleum products.

GRADES AT ONCE

Up to 6+

TANK LINING

Epoxy or stainless

PUMPS

One per tank

CODE

IBC Code

Unpackaged dry cargo poured straight into the holds: iron ore, coal, grain, bauxite, alumina, cement, fertiliser, salt and scrap. Some cargoes can shift or liquefy, which makes stability calculation and moisture certification part of the loading process, not an afterthought.

• Handysize 10,000–35,000 dwt. Geared, and able to work minor ports.
• Handymax / Supramax 35,000–60,000 dwt, usually with four cranes.
• Panamax 60,000–80,000 dwt, sized to the canal locks.
• Kamsarmax About 82,000 dwt — the maximum length for Port Kamsar, Guinea.
• Capesize 100,000–200,000 dwt. Too large for the canals, so they route via the Capes.
• VLOC Very Large Ore Carrier, above 200,000 dwt, on dedicated iron ore routes.

GEARED

Cranes fitted

GEARLESS

Shore gear only

HOLDS

5–9

CARGO RISK

Shifting, liquefaction

Natural gas cooled to liquid at −162 °C, which shrinks it to about 1/600th of its gas volume. The cargo is never fully static: heat leaks in, some cargo boils off, and that boil-off gas is either reliquefied or burned as fuel in the main engine.

• Moss spherical Self-supporting aluminium spheres — the distinctive domed profile.
• GTT membrane Thin membrane bonded to the inner hull. Mark III and NO96 dominate new orders.
• Type C tanks Pressure vessels used on small-scale and bunkering vessels.
• Conventional 145,000–174,000 m³ — the standard trading size today.
• Q-Flex About 210,000 m³, with onboard reliquefaction.
• Q-Max About 266,000 m³, the largest LNG carriers built.

CARGO TEMP

−162 °C

TYPICAL SIZE

174,000 m³

PROPULSION

DFDE · ME-GI · XDF

CODE

IGC Code

Liquefied petroleum gases — propane and butane — plus ammonia, propylene, butadiene and vinyl chloride. The cargo is kept liquid either by pressure, by refrigeration, or by a combination of both, and which method a ship uses defines the whole vessel.

• Fully pressurised Type C tanks at ambient temperature. Small ships, simple plant.
• Semi-refrigerated Part-cooled and part-pressurised. The most flexible type.
• Fully refrigerated Type A tanks near atmospheric pressure at −48 °C for propane.
• Handysize About 15,000–25,000 m³, often ethylene-capable.
• MGC / LGC Midsize and Large Gas Carriers, 25,000–70,000 m³.
• VLGC Very Large Gas Carrier, around 84,000 m³ and now up to 93,000 m³.

CARGOES

Propane, butane, NH₃

PROPANE TEMP

−48 °C

TANK TYPES

A · B · C

CODE

IGC Code

Anything with wheels. Trailers, unaccompanied semi-trailers, trucks, buses, agricultural and construction machinery, and on some routes rail wagons. Cargo drives on over a ramp and is lashed to deck sockets, so capacity is measured in lane metres rather than tonnes.

• Pure Ro-Ro Freight only — trailers and rolling machinery, no passengers.
• RoPax Combined freight and passengers on scheduled ferry routes.
• ConRo Ro-Ro decks below, container stacks above. Common on North Atlantic trades.
• RoLo hybrid Ramp access plus lift-on/lift-off hatches for non-rolling cargo.
• Stern ramp The standard access; quarter ramps allow berthing where space is tight.
• Stability note Large undivided decks mean free surface effect is watched closely.

CAPACITY UNIT

Lane metres

TYPICAL

4,000 m+

ACCESS

Stern / quarter ramp

PORT STAY

Hours

New and used vehicles, and on truck-capable ships, buses, tractors and high-and-heavy plant. Capacity is counted in CEU — car equivalent units, based on a standard hatchback. Decks are stacked a few metres apart, and some are liftable to make room for taller cargo.

• PCC Pure Car Carrier — cars only, fixed deck heights.
• PCTC Pure Car and Truck Carrier, with liftable decks and heavier deck strength.
• Small / regional Under about 4,000 CEU on short-sea and feeder routes.
• Standard Roughly 6,000–7,000 CEU, 12–14 decks, the mainstay of the fleet.
• Large PCTC 8,000 CEU and above on the main deep-sea routes.
• Handling note Huge slab sides give enormous sail area in a beam wind.

CAPACITY UNIT

CEU

TYPICAL

6,000–8,000 CEU

DECKS

12–14

LIFTABLE DECKS

Yes, on PCTC

Cargo that does not fit a standard mould: steel coils, plate and pipe, bagged cement and rice, sawn timber, machinery, transformers, wind turbine blades and yachts. Often loaded in ports with no terminal equipment, which is why most of these ships carry their own cranes.

• Multipurpose (MPP) Boxed, bulk or break bulk in the same holds. The most common type.
• Geared Fitted with 30–80 tonne cranes, and able to work anywhere.
• Tweendecker Extra intermediate decks to separate and support mixed parcels.
• Heavy-lift Reinforced tank tops and cranes able to combine for 500 t+ single lifts.
• Open-hatch Box-shaped holds with hatches full width, for forest products and unit loads.
• Trade pattern Mostly tramp — no fixed schedule, cargo by cargo.

GEAR

30–80 t cranes

HEAVY-LIFT

Up to 900 t

TRADE

Tramp

CARGO MIX

Very high

Everything a rig, platform or wind farm needs: drilling mud and cement in tanks, casing and tubulars on deck, fuel, fresh water, provisions, and the technicians themselves. Passages are short and intense, and the ship often works with no berth at all.

• PSV Platform Supply Vessel. Deck cargo plus liquid mud, brine and cement in tanks.
• AHTS Anchor Handling Tug Supply. Tows rigs and runs their anchors, with huge bollard pull.
• OSCV Offshore Subsea Construction Vessel, with a heavy crane and moonpool.
• DSV Diving Support Vessel with saturation diving systems.
• SOV / W2W Service Operation Vessels with motion-compensated gangways for wind farms.
• DP class DP1, DP2 or DP3 — the level of redundancy in dynamic positioning.

STATION KEEPING

DP2 / DP3

CREWING

Rotational

DECK CARGO

Tubulars, containers

PASSAGE

Short

People. Which changes everything: passenger ship regulations, a hotel department larger than the marine crew, medical facilities, and Safe Return to Port rules requiring the ship to remain habitable and able to make harbour after serious damage.

• Expedition Under about 500 passengers, ice-strengthened for polar and remote trades.
• Small / luxury Roughly 500–1,500 passengers, able to enter smaller ports.
• Mid-size About 1,500–3,000 passengers on mainstream itineraries.
• Mega / large resort 3,000–7,000+ passengers, over 200,000 GT.
• Propulsion Diesel-electric with azimuth thrusters, giving very fine manoeuvring.
• Regulatory Passenger ship SOLAS chapters, damage stability and Safe Return to Port.

SOULS ABOARD

Up to 8,000+

CREW

1,000–2,300

PROPULSION

Diesel-electric

MEASURE

GT, not dwt