Answer
The definition of a bulk carrier varies slightly across different chapters of SOLAS depending on when the vessel was constructed and which specific regulations apply. For oral exams, you must state these distinct definitions precisely.
1. As per SOLAS Chapter IX (Regulation 1.6) & The ISM Code
This is the Structural Definition. Under Chapter IX (Management for the Safe Operation of Ships), which makes the ISM Code mandatory, a bulk carrier is defined strictly by its physical geometric design.
Definition: "Bulk carrier means a ship which is constructed generally with a single deck, top-side tanks, and hopper side tanks in cargo spaces, and is intended primarily to carry dry cargo in bulk, and includes such types as ore carriers and combination carriers."
International Maritime Organization
Key Takeaway for Orals: If a ship does not have the classic structural blueprint (top-side wing tanks and hopper tanks), it is not a bulk carrier under Chapter IX / ISM.
2. As per SOLAS Chapter XII (Regulation 1.1)
This is the Operational / Intent-Based Definition, introduced via amendments (Resolution MSC.170(79)) to clear up structural loopholes for newer vessels. It focuses on the vessel's primary utility rather than just its hull geometry.
Definition: "Bulk carrier means a ship which is intended primarily to carry dry cargo in bulk, including such types as ore carriers and combination carriers."
The Crucial Construction Date Split (1 July 2006)
To satisfy Chapter XII safety standards, the code splits ships based on their keel-laying date:
Ships constructed BEFORE 1 July 2006: They must strictly fit the traditional structural definition given in Chapter IX (single deck, top-side tanks, hopper tanks) to be legally designated a bulk carrier.
Ships constructed ON or AFTER 1 July 2006: Any ship designed primarily to carry dry cargo in bulk is a bulk carrier, even if it lacks traditional top-side or hopper side tanks. This encompasses modern configurations like:
Open-hatch bulk carriers
Dedicated woodchip/timber carriers (box-type)
Dedicated cement or fly-ash carriers
Explicit Exemption: It completely excludes vessels where the cargo spaces are structurally built like a cellular container ship.