Heeling Error

In these days of GPS navigation, people tend to ignore changes in deviation caused when the boat heels and lumps of structural iron alter their relationship with the compass. Some boats, especially those with iron keels, can exhibit enough ‘heeling error’ to make a significant…

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Don’t believe the helmsman

Every skipper should be aware that helmsmen or even women rank among the world’s most chronic liars. It isn’t that they’re born crooked, it’s just that fore-and-aft-rigged sailing yachts on a reach all want to screw up to windward. Broad-beamed modern craft are specialists, but…

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Datums for GPS

If you’re still struggling with chart datums for GPS, YM’s postbag indicates that you’re not alone! Search an Admiralty chart and you’ll find a statement like this one. Once you know your chart’s datum – in this case ‘Ordnance Survey of Great Britain (OSGB) 1936…

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