Deck General: Seamanship, Stability, and Pollution Prevention
Anchoring and mooring
Deck General blends seamanship with practical vessel knowledge. For anchoring, know the parts of the ground tackle and the idea of scope: the ratio of rode length to water depth. A common rule is at least 5:1, with about 7:1 typical for chain in ordinary conditions and more in heavy weather. Understand veering chain, setting the anchor, dragging, and the advantage of catenary. For mooring, know head, stern, spring, and breast lines: head and stern lines control fore-and-aft position, spring lines oppose fore-and-aft motion, and breast lines lead roughly perpendicular to the hull.
Lines, knots, and deck equipment
Know the bowline (fixed loop), clove hitch (temporary tie to a rail or post), round turn and two half hitches, sheet bend (joining lines of unequal size), reef knot, and rolling hitch. Understand right-laid versus left-laid line, wire rope construction, blocks and mechanical advantage, and the difference between a simple purchase and a gun tackle.
Stability and loading
Know GM, KG, free surface, list, trim, drafts, and the load line. Positive GM means initial stability; too much GM gives a stiff, rapid roll, while too little gives a tender vessel. Free surface effect reduces effective GM. High KG reduces stability. Always check drafts and load line marks before loading.
Traps and pollution rules
Questions often confuse line names, knot uses, or stability terms. For pollution, remember that plastics may never be discharged overboard and that oil and garbage record book requirements depend on vessel size and trade. Read the stem carefully: it may ask about Annex I, IV, or V.
Rule of thumb
Anchor scope about 7:1 in normal weather; if the anchor drags, pay out more chain before attempting to reset.