Types of Tankers Flashcards
7 cards from real Tanker Familiarization practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
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What is the main operational difference between a ULCC and a VLCC?
Answer: ULCCs exceed 320,000 DWT and are the largest crude carriers, while VLCCs are 200,000–320,000 DWT
Ultra Large Crude Carriers (ULCCs) exceed 320,000 DWT and represent the largest class of tankers, while VLCCs range from about 200,000 to 320,000 DWT.
A 'membrane' LNG tank system, such as those used on most LNG carriers, relies on:
Answer: A thin metallic membrane supported by the ship's hull insulation system
Membrane containment systems use a thin, corrugated metallic layer (e.g., Invar or stainless steel) that is supported by and transfers load to the insulation and the ship's inner hull.
Which tanker type would typically be employed on the 'dirty' petroleum product trade?
Answer: Product tanker carrying fuel oil and crude
The 'dirty' product trade refers to heavier, residual petroleum products such as fuel oil, which are typically carried by product tankers or crude tankers with uncoated mild-steel tanks.
How do Moss-type (spherical) LNG tanks differ from membrane tanks?
Answer: Moss tanks are self-supporting spheres that stand independently inside the cargo holds
Moss-type tanks are large independent spherical tanks made of aluminum alloy that are structurally self-supporting and sit in cylindrical skirts within the cargo hold.
Which international regulation phased out single-hull crude oil tankers above 5,000 DWT?
Answer: MARPOL Annex I Regulation 13G/20
MARPOL Annex I, particularly Regulation 13G (later updated as Regulation 20), established a schedule to phase out single-hull tankers and require double-hull construction.
A 'combination carrier' such as an OBO vessel is designed to carry:
Answer: Ore, bulk cargo, or oil, switching between cargo types on different voyages
OBO (Oil-Bulk-Ore) combination carriers can load crude oil in some voyages and bulk commodities such as iron ore or grain on others, improving fleet flexibility and reducing ballast voyages.
What is the primary reason asphalt (bitumen) tankers require heated cargo tanks?
Answer: Asphalt is highly viscous and must be kept at elevated temperatures (typically 150–200°C) to remain pumpable
Bitumen solidifies at ambient temperatures, so asphalt tankers use heating coils or other systems to maintain cargo temperature above 150°C to keep it fluid enough to pump.