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Sailing reference
Clear explanations of the language used in navigation, pilotage, weather, safety and life under sail.
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The international rules of the road for preventing collisions at sea
The Convention on the International Regulations for Preventing Collisions at Sea 1972, as amended, applies to all vessels on the high seas and connected navigable waters. Part B, the steering and sailing rules, is divided into three sections: conduct in any condition of visibility, conduct of vessels in sight of one another, and conduct in restricted visibility. Local authorities may issue special rules for harbours and inland waters, which must conform as closely as possible to the international rules.
Read definition →Fitting magnets and iron to cancel a vessel's compass error
A qualified adjuster reduces deviation by placing fore and aft and athwartships corrector magnets to counter permanent magnetism, a vertical soft iron Flinders bar to counter induced vertical field effects that vary with latitude, and quadrantal spheres of soft iron either side of the binnacle to counter induced horizontal effects on intercardinal headings. Heeling error magnets sit beneath the card. After adjustment the residual deviation is measured and recorded on a fresh card.
Read definition →The rotating dial and the fixed mark you read it against
The card carries the graduations, historically in points of 11.25 degrees and now in degrees from 000 to 359, and is attached to the magnet assembly so it stays aligned with the field while the vessel turns about it. The lubber line is the fixed reference on the bowl, which must be aligned precisely with the fore and aft line; any misalignment introduces a constant error on every heading that will be misread as deviation.
Sailing reference
Clear explanations of the language used in navigation, pilotage, weather, safety and life under sail.