Question 1

As Chief Mate of a 15-year-old Handymax bulk carrier, your examiner asks about the structural hazards specific to bulk carriers and what pre-loading inspections are required.

Accepted Answer

Bulk carrier structural hazards: transverse frames and frames at the lower hopper angles are susceptible to corrosion — section loss reduces capacity to withstand cargo and water pressure; topside tank inner structure (frames, longitudinals) can corrode from condensation; hold bilge systems can become blocked leading to flooding; hatch coaming knees and corners are high-stress areas prone to cracking. Pre-loading inspections required: visual inspection of all cargo hold frames for excessive corrosion, cracks, or deformation; measure any suspect frame section loss against class thickness limits; inspect bilge wells and ensure suctions are clear; test bilge systems before loading; verify hatch cover weathertightness; check hold structural condition report in class records. A "substantiated doubt" of structural deficiency found by PSC can require survey before departure. Bulk carrier structural safety has been a major IMO focus since the catastrophic losses of the 1980s-1990s (Derbyshire, Flare, Melete, Arktea — all total losses with all crew). The Enhanced Survey Programme (ESP) for bulk carriers (IMO Res. A.744(18)) requires detailed close-up surveys and thickness measurements at defined intervals. But between class surveys, the Chief Mate has a duty of care to identify visible deterioration. The IMO Guidelines for Surveys of Aged Bulk Carriers (MSC/Circ.1040) and IACS common structural rules address corrosion margin and allowable section loss. In practice: a frame with visible wastage (deep pitting, section loss, deformation) in a high-stress location (lower bracket area, bilge strake connection) can constitute a class deficiency requiring steel renewal before further loading. The Chief Mate is the primary person on board with technical knowledge to identify these issues — if in doubt, seek a class surveyor before loading heavy ore cargo.

Question 2

As Chief Mate, you receive a Dangerous Goods Declaration for 12 drums of methyl ethyl ketone peroxide (Class 5.2 — organic peroxide). The manifest states "Type C." Your examiner asks what your responsibilities are before loading.

Accepted Answer

Before loading Class 5.2 organic peroxides: verify the Dangerous Goods Declaration is complete and accurate (UN number, proper shipping name, class, packing group, flashpoint, emergency contact). Check the IMDG Code entry for MEKP Type C — organic peroxides have temperature control requirements (SADT — self-accelerating decomposition temperature) and require controlled temperature stowage. Verify the shipper has provided a Certificate of Analysis confirming temperature control requirements are met. Check segregation against other cargo — Class 5.2 must be segregated from flammable materials. Confirm the ship has the required equipment (temperature monitoring, fire extinguishers of correct type). Inform master and company if any requirements cannot be met. The Chief Mate signs the cargo receipt — this is a legal acknowledgement of receipt in apparent good order. Organic peroxides (Class 5.2) are among the most dangerous IMDG cargoes — they can decompose exothermically and trigger fires or explosions. MEKP (Methyl Ethyl Ketone Peroxide) is used in fibreglass manufacturing and is highly reactive. The IMDG Code Subdivision 5.2 lists organic peroxides by type (A through G) — Type A is prohibited from sea transport; Type B requires temperature control and specific packaging. The SADT (Self-Accelerating Decomposition Temperature) is the minimum temperature at which the substance will decompose in the packaging used — if ambient temperature approaches SADT, cooling must be provided. At Chief Mate level, the examiner expects candidates to know: (a) the special provisions for the specific cargo; (b) the temperature monitoring and emergency cooling requirements; (c) stowage requirements (often "on deck away from living quarters" or "under deck in a cool, well-ventilated space"). Responsibility is shared — the shipper provides the declaration, the Chief Mate verifies it is plausible and meets carriage requirements.

Question 3

As Chief Mate on a 2,500 TEU container vessel, you are planning a container load with 180 refrigerated containers concentrated in the aft holds. Your examiner asks what loading challenges this creates and how you address them.

Accepted Answer

Concentrating 180 reefer containers aft creates: a stern trim (aft deeper than forward) which increases propeller immersion and may benefit fuel consumption but limits forward visibility, raises bow out of water (slamming risk), and increases SF at the aft hold section; a very high stack weight concentration aft that affects both bending moment (increased hogging tendency forward of the concentration) and longitudinal strength; reefer containers typically have a higher average weight than dry boxes. Address: use the loading computer to calculate SF/BM values for the proposed plan — adjust stack heights and position to bring values within limits; plan ballast distribution to counteract the trim if excessive; check stack stability and tier limits for the aft positions. Confirm electrical load calculations for 180 reefer plugs simultaneously. Container ship cargo planning at Chief Mate level requires simultaneous consideration of stability (GM, GZ), longitudinal strength (SF/BM), trim, and operational factors (visibility, slamming, propeller immersion). Stack weight limits: each container bay position has a maximum stack weight (tonnes per 20ft bay) and a maximum tier height — exceeding these causes structural damage to the vessel's cell guides or hatch covers. The loading computer (approved by class) integrates all these parameters. Reefer considerations: 180 reefer containers operating simultaneously represent a significant electrical load — the chief engineer must confirm generator capacity. Cold chain integrity: reefer containers need monitoring — the Chief Mate is responsible for ensuring containers are connected and temperature records are maintained. Trim: IACS has issued guidelines on trim and stability for container vessels — excessive stern trim on a container ship raises the bow which increases slamming forces in head seas, potentially damaging forward deck fittings and cargo.