Your vessel is a bulk carrier over 150m LOA, built in 1998. The examiner asks about the Enhanced Survey Programme (ESP) requirements that apply to this vessel and what the chief mate's responsibilities are in relation to structural surveys.

A. SOLAS XII AND ENHANCED SURVEY PROGRAMME: SOLAS CHAPTER XII: Additional safety measures for bulk carriers — applies to single-side-skin bulk carriers over 150m LOA. KEY REQUIREMENTS: (1) Mandatory cargo hold and ballast tank structural surveys; (2) Moisture content and density certificate requirements for solid bulk cargoes; (3) Loading instrument required (LOADICATOR for BC over certain size); (4) BC Code compliance. ENHANCED SURVEY PROGRAMME (ESP): IACS URE 10 defines the Enhanced Survey Programme for bulk carriers. A vessel built in 1998 will be in the 25+ year age bracket — highest inspection intensity: CLOSE-UP SURVEYS: A greater proportion of structural elements require close-up inspection at each survey (Annual, Intermediate, Special). CHIEF MATE'S RESPONSIBILITIES: (1) SURVEY PREPARATION: ensure hold and tank access ladders, lighting, and ventilation are ready for class surveyor visits; (2) THICKNESS MEASUREMENT RECORDS: maintain and make available previous thickness measurement (TM) records — the trend of steel wastage is assessed over time; (3) STRUCTURAL DEFECT REPORTS: ensure all defects found during deck inspection are logged and reported so surveyors have the complete picture; (4) HOLD COATING RECORDS: record condition of hold coatings — coating breakdown accelerates corrosion and is noted in survey records; (5) The chief mate is the officer most likely to accompany the surveyor in cargo holds — must know what the surveyor is looking for.

B. The Enhanced Survey Programme applies only to vessels built after 2000. A vessel built in 1998 follows the standard annual survey programme with no enhanced requirements.

C. Enhanced surveys are conducted exclusively by classification society surveyors. The chief mate has no responsibility in relation to structural surveys — this is a purely engineering and survey function.

D. SOLAS XII only applies to tankers. Bulk carriers follow the IMSBC Code for structural requirements, not SOLAS.

A. BENDING MOMENT AND SHEAR FORCE — CONCEPTS AND ACTION: BENDING MOMENT (BM): the internal moment within the ship's hull that resists the tendency of the vessel to "hog" (bend upwards at the centre when supported at ends) or "sag" (bend downwards at the centre when buoyancy exceeds weight amidships). BM is measured in tonne-metres and varies along the ship's length. SHEAR FORCE (SF): the internal vertical force within the hull at any cross-section — the tendency of the ship to "shear" (vertical displacement between adjacent sections). Caused by unequal distribution of weight and buoyancy. STILL WATER vs WAVE BM: still water BM is calculated at the loading port and is the controllable component. Wave BM is added at sea and is the classification society's additional allowance. MAXIMUM PERMISSIBLE STILL WATER BM: the value stated in the ship's loading manual is the maximum still water BM that the vessel's structure can withstand in still water, with a reserve for wave-induced BM at sea. EXCEEDING THE LIMIT: the proposed sequence results in 9,100 vs maximum 8,500 tonne-metres — this is 7% over the permissible limit. THE VESSEL MUST NOT SAIL in this condition. ACTION REQUIRED: (1) Modify the loading sequence — redistribute cargo between holds; (2) Add ballast to alter buoyancy distribution; (3) Reduce total cargo weight; (4) Recalculate until within limits; (5) Document the revised plan and recheck BM and SF on the loading computer.

B. The maximum permissible value is a conservative limit with a 10% tolerance built in. A bending moment 7% over the stated limit is within the safety margin and the vessel may sail.

C. Shear force and bending moment limits only apply in port loading operations. At sea, wave action overrides the still water values and the loading computer limits are not relevant.

D. Contact the classification society for a dispensation to sail over the limit. Classification societies routinely grant dispensations for temporary bending moment exceedances at loading ports.

A. HOGGING AND SAGGING — DEFINITIONS AND CAUSES: SAGGING: the vessel bends so that the midship section is lower than the bow and stern — the hull curves downward like a banana shape with the centre lowest. CAUSES: (a) Heavy cargo concentrated amidships with relatively empty ends — weight exceeds buoyancy amidships; (b) At sea: when the vessel is in the trough of a wave — buoyancy is reduced amidships (both bow and stern supported by wave crests). STRESS IN SAGGING: the keel and bottom structure are in TENSION; the deck structure is in COMPRESSION. HOGGING: the vessel bends so that the midship section is higher than the bow and stern. CAUSES: (a) Heavy cargo at the ends with a light or empty midships section; (b) At sea: when the vessel is at the crest of a wave — midships is supported by the wave while bow and stern overhang the troughs. STRESS IN HOGGING: the deck is in TENSION; the keel is in COMPRESSION. PRACTICAL SIGNIFICANCE: most bulk carriers are more vulnerable to hogging in heavy weather (empty holds or light cargo at midships with heavy ore at ends). Structural failures have occurred from excessive hogging loads in severe weather. LOADING TO BALANCE: a well-loaded bulk carrier distributes heavy cargo to minimise both sagging and hogging BM — check the loading computer output for the BM envelope diagram.

B. Sagging occurs when the bow is heavily loaded and the stern is light. Hogging occurs when the stern is heavily loaded and the bow is light.

C. Hogging and sagging refer to the list of the vessel, not bending. A hogged vessel lists to port, a sagged vessel lists to starboard.

D. Sagging is when the vessel is heavy overall and riding low in the water. Hogging is when the vessel is light and riding high. Both are stability terms, not structural terms.