Question 1

Your vessel arrives at a bulk terminal to load 35,000 tonnes of coal. You currently have double-bottom ballast tanks full (10,000 tonnes total) and all topside tanks empty. The terminal wants to start loading into holds 1, 2, and 3 simultaneously. As Chief Mate, what structural considerations govern your loading plan?

Accepted Answer

Simultaneous loading into holds 1, 2, and 3 with full double-bottom ballast creates concentrated weight amidships-forward while the aft body remains relatively light — this creates a hogging tendency amidships. As coal is loaded in the forward holds, the bending moment will increase rapidly. The loading computer must be used to check BM and SF values at each stage. Double-bottom ballast must be progressively deballasted as cargo is loaded to prevent exceeding structural limits — the sequence of deballasting (aft tanks first, then midship, then forward) must be planned to maintain SF/BM within limits while also keeping stability adequate during the deballasting phase. Never deballast forward tanks while loading forward holds simultaneously — this creates a rapid reduction in forward buoyancy combined with increasing forward weight. Bulk carrier loading sequence planning is a core Chief Mate management function and is specifically examined at this level. The structural risk during loading: if cargo is loaded too fast into forward holds without deballasting, the forward hull section carries both the new cargo weight and the existing ballast weight simultaneously — the bending moment at the midship section increases dramatically, potentially exceeding class structural limits. This is not a theoretical risk — there have been structural failures during loading operations in port (reported to MAIB and classification societies). The Chief Mate must: (a) calculate the loading plan step by step using the loading computer; (b) identify the maximum allowable cargo load at each stage before deballasting must begin; (c) communicate the sequence constraints clearly to the terminal before operations begin — terminals work to commercial speed targets and will not automatically consider structural sequencing; (d) have authority to slow or stop loading if structural limits are approached. This authority is supported by ISM Reg 5 (master's overriding authority — delegated to Chief Mate for cargo operations).

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 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.