Oil Tanker Types: Sizes, Classes and Classification

Oil tanker types are classified three ways: by cargo, by size and by MARPOL category. This hub explains each system and links to the detailed page for every class, for ship’s officers, surveyors, chartering staff and maritime students.

What Are the Main Types of Oil Tankers?

The two main oil tanker types are crude oil tankers and product tankers. Crude tankers carry unrefined crude to refineries; product tankers carry refined fuels to markets. A smaller group of specialised tankers covers niche trades.

• Crude oil tankers: large, uncoated or partly coated ships carrying one or a few crude grades on long-haul routes.
• Product tankers: smaller ships with coated tanks and more segregations, carrying several refined grades at once.
• Specialised oil tankers: shuttle tankers serving offshore fields and bitumen tankers carrying hot asphalt.

What Is a Crude Oil Tanker?

A crude oil tanker carries unrefined crude oil in bulk, usually from a producing region to a refinery. Crude carriers are the largest oil tankers afloat, from Aframax up to VLCC and ULCC size.

Crude tankers clean their tanks with crude oil washing and run an inert gas system throughout cargo operations. Their cargo handling systems are built for high discharge rates of a few grades rather than many small parcels.

What Is a Product Tanker?

A product tanker carries refined petroleum products such as gasoline, jet fuel, diesel and naphtha. It has coated cargo tanks and more independent cargo segregations than a crude carrier, so it can load several grades without cross-contamination.

Many product tankers also hold IMO Type 2 or Type 3 chemical tanker certificates. That lets them carry vegetable oils and easy chemicals between fuel cargoes. Smaller units may have stainless steel tanks for more demanding chemical cargoes.

What Is the Difference Between Clean and Dirty Tankers?

Clean tankers carry clean petroleum products (CPP) such as gasoline, jet fuel and diesel. Dirty tankers carry dirty petroleum products (DPP) and crude, including fuel oil. The split matters because a dirty tanker must clean its tanks thoroughly before a clean cargo.

Most crude carriers trade dirty for their whole life. Product tankers, especially LR2s, can switch between clean and dirty trades, but returning to clean cargo after fuel oil takes tank cleaning, time and inspection.

How Are Oil Tankers Classified by Size?

Oil tankers are grouped into size classes by deadweight tonnage (dwt). Crude carriers run from Panamax to ULCC, while product tankers use the General Purpose, Medium Range and Long Range classes. Class boundaries vary slightly between brokers.

Class	Approx. deadweight	Typical cargo	Defining limit or trade
General Purpose (GP)	10,000–25,000 dwt	Refined products	Coastal and regional distribution
Medium Range (MR)	25,000–55,000 dwt	Refined products, easy chemicals	Workhorse of the product trade
Panamax / LR1	55,000–80,000 dwt	Crude (Panamax) or products (LR1)	Original Panama Canal locks
Aframax / LR2	80,000–120,000 dwt	About 750,000 barrels	Regional crude and long-haul products
Suezmax	120,000–200,000 dwt	About 1 million barrels	Suez Canal draft when loaded
VLCC	200,000–320,000 dwt	About 2 million barrels	Long-haul crude, deepwater terminals
ULCC	320,000–550,000 dwt	2–3.7 million barrels	A handful of deepwater terminals

What Is a Panamax Tanker?

A Panamax tanker is built to the maximum size of the original Panama Canal locks. Those locks limit beam to 32.3 m (106 ft), length overall to 289.6 m and draft to 12.04 m in tropical fresh water.

Panamax crude tankers typically fall between about 55,000 and 80,000 dwt and trade within the Americas and the Caribbean. The expanded canal locks, open since 2016, accept Neopanamax ships up to 366 m long, 51.25 m in beam and 15.2 m draft.

Canal transit rules come from the canal authority, not class. The Panama Canal page covers the locks and their history.

What Is an Aframax Tanker?

An Aframax tanker is a medium-sized crude carrier of about 80,000–120,000 dwt, carrying around 750,000 barrels. The name comes from the Average Freight Rate Assessment (AFRA), a tanker rate system Shell introduced in 1954.

Aframaxes dominate regional crude trades such as the North Sea, the Mediterranean, the Black Sea and the Caribbean. Many ports that cannot take a Suezmax can take an Aframax, which keeps the class in constant demand.

What Is a Suezmax Tanker?

A Suezmax is the largest tanker that can transit the Suez Canal fully loaded. It is typically around 160,000 dwt and carries about one million barrels. The canal allows a maximum draft of 20.1 m (66 ft).

At that draft, beam is limited to 50 m. Suezmaxes carry crude from West Africa, the Black Sea and the Mediterranean to Europe and the United States, as well as through the canal itself.

What Are VLCCs and ULCCs?

VLCCs (200,000–320,000 dwt) and ULCCs (320,000–550,000 dwt) are the largest crude carriers, built for long-haul trades between deepwater terminals. A VLCC carries about two million barrels; a ULCC carries roughly 2 to 4 million.

Both are too deep to transit the Suez Canal fully laden. The largest VLCCs, known as Malaccamax, are built to the deepest draft the Strait of Malacca allows. Very few ULCCs remain in trading service; the ULCC page covers the class in detail.

What Are GP, MR, LR1 and LR2 Product Tankers?

GP, MR, LR1 and LR2 are the product tanker size classes, rising from General Purpose through Medium Range to Long Range 1 and 2. The labels come from the AFRA scale and remain standard in chartering.

• General Purpose (GP): small product tankers for coastal and short-sea distribution.
• Medium Range (MR): the largest product tanker fleet, flexible enough for most product terminals and many easy chemicals.
• Long Range 1 (LR1): a coated Panamax-size product tanker for long-haul clean trades.
• Long Range 2 (LR2): a coated Aframax-size product tanker that can switch between clean and dirty cargoes.

What Is the Difference Between LR1 and LR2 Tankers?

An LR1 is roughly Panamax size (about 55,000–80,000 dwt) and an LR2 roughly Aframax size (about 80,000–120,000 dwt). Both have coated tanks. LR2s carry larger parcels on longer routes and switch more often between clean and dirty products.

What Are Shuttle Tankers?

Shuttle tankers carry crude oil from offshore production fields to shore terminals over relatively short distances. They load at sea from platforms, buoys or floating storage units rather than at a conventional berth.

• Bow loading: cargo comes aboard through a bow loading system connected to the offshore installation.
• Station keeping: dynamic positioning systems hold the ship in position while loading.
• Main regions: developed for the North Sea and now widely used off Brazil and in other offshore fields without export pipelines.

How Do Oil Tankers Differ From Other Tanker Types?

Oil tankers are one of three main tanker families. Chemical tankers carry noxious liquid substances under the IBC Code, and gas carriers carry liquefied gases under the IGC Code. Each family has its own construction rules and size classes.

• Oil tankers: crude and refined petroleum under MARPOL Annex I, covered on this page.
• Chemical tankers: classed as IMO Type 1, 2 or 3 by cargo hazard under the IBC Code.
• Gas carriers: LNG and LPG carriers built to the IGC Code; see the types and sizes of LNG carriers.
• Bitumen tankers: a niche oil tanker type carrying hot asphalt in insulated independent tanks.

What Regulations Govern Oil Tankers?

Oil tankers are regulated mainly by MARPOL Annex I for pollution and SOLAS for safety. Flag states, class societies and port state control enforce them. Industry standards from OCIMF add the commercial vetting layer charterers rely on.

• MARPOL Annex I: double-hull construction, slop tank arrangements, the oil discharge monitoring system and the Oil Record Book.
• SOLAS: fire protection of the cargo area, the inert gas system and cargo tank venting through P/V valves.
• ISM Code: the company safety management system that covers cargo, ballast and tank cleaning procedures.
• Canal, port and regional authorities: canal size and draft limits, terminal rules, and regional regimes such as the US Coast Guard and EU requirements.
• OCIMF: industry guidance and the SIRE inspection programme used for tanker vetting.

What Are Category 1, 2 and 3 Oil Tankers?

MARPOL Annex I sorted tankers into three categories to phase out single-hull ships. The categories set the deadlines by which single-hull tankers had to leave service or meet double-hull standards.

• Category 1: older “pre-MARPOL” tankers without protectively located segregated ballast tanks. The size threshold is 20,000 dwt for crude, fuel oil, heavy diesel oil or lube oil, and 30,000 dwt for other oils.
• Category 2: tankers of the same size thresholds built to the MARPOL 73/78 segregated ballast standards.
• Category 3: tankers of 5,000 dwt and above below those thresholds.

The single-hull phase-out is complete under MARPOL. The categories still appear in older documents and some flag and port state rules, so surveyors meet them on records rather than on ships.

How Do Classification Societies Oversee Oil Tankers?

A classification society approves the tanker’s design, surveys its construction and keeps it in class through periodic surveys. For oil tankers, IACS members apply common structural rules and an enhanced survey programme.

• Common Structural Rules: IACS rules that set hull scantlings for double-hull oil tankers of 150 m length and above.
• Enhanced Survey Programme (ESP): mandatory under SOLAS Chapter XI-1, it adds close-up surveys and thickness measurements of cargo and ballast tanks as the ship ages.
• Class notations: record the ship’s service, such as oil tanker, oil/chemical tanker or ESP, and any additional features.

What Do Inspectors Check on Oil Tankers?

Oil tankers face three inspection regimes. Class surveyors check hull condition under the ESP, and port State Control checks MARPOL and SOLAS compliance. Vetting inspectors assess operations before a charterer accepts the ship.

Class and statutory surveys. At intermediate and renewal surveys, ESP close-up inspections and thickness gauging focus on cargo and ballast tanks. Coating breakdown in ballast tanks and corrosion in cargo tank bottoms are the classic findings on ageing tankers.

Port State Control. PSC officers check the IOPP Certificate, Oil Record Book Part II, ODME records, inert gas system operation and cargo area fire protection. Serious failures in any of these are grounds for detention.

Vetting. Oil majors and charterers rely on a vetting inspection under OCIMF’s SIRE programme before fixing a tanker. Inspectors review cargo, mooring and safety management practices, and poor results can keep a ship out of the market.

Related Topics

• 10 Largest Oil Tanker Companies in the World
• Types of Cargo Ships
• How Much Fuel Does a Cargo Ship Use?
• Types of Gas Carriers as per IGC Code

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