Structure and stresses
The ship is built with a framing system — keel, floors, frames, stringers, girders, deep beams, bulkheads and pillars — carrying the loads into the structure, subdivided by watertight and fire-rated divisions. The hull endures longitudinal stresses (hogging and sagging as waves pass, plus stresses from uneven loading), and local stresses (panting, pounding, racking and vibration), with fatigue cracks starting at discontinuities such as hatch corners. The Master loads the ship so the loading itself does not overstress her, and reports structural defects found on rounds.
Survey and certification
- The ship is classed by a classification society (an IACS member) that surveys her through her life to a class notation.
- Statutory certificates — safety, load line, pollution, radio — are issued and surveyed under the flag State, with Port State Control checking compliance.
- The Master plans survey items into the maintenance programme and keeps the certificates and records in order.
- Corrosion is controlled by coatings and cathodic protection; the Master ensures the anodes and coatings are maintained.
NOTE — No surprises at survey Survey readiness comes from planning survey items into the maintenance programme and keeping honest records, so a surveyor's visit confirms what the Master already knows rather than uncovering neglect.
WARNING — Load within the hull's strength Concentrating weight in the ends or amidships adds to the wave-induced hogging and sagging and can overstress the hull. The Master distributes weight so the loading itself does not strain the ship.