ASTERN White sails of Dover
FAMILIAR SIGHTS
Celebrating life on the water MOUNTING KNOWLEDGE
˅˘˖˘˧ ˦˖˜˘˧˜Ѓ˖ Ѓ˗˜˚˦ ˛˔˩˘ shown how underwater mountains impact ocean temperature. Called seamounts, these towering structures cause turbulence around them, which pulls up deep and carbon-heavy water to the surface.
A metre-ing of minds
To make trade fairer and help international innovation, 19 countries signed the Metre Convention 150 years ago to allow for the standardisation of measurements.
In March the sun shone as
ʷ˩˘˥ ʻ˔˥˕˨˥ ˔˦ Ѓ˘˗ ˜˧˛ ˗˜˚˛˜˘˦ ˖˘ ˔˚˔˜ʡ ʴ ˚ ˧˜ˠ˘˛˔˗ ˣ˔˦˦˘˗ ˦˜˖˘ ˧˛˘˛˔˥˕˨˥ ˣ˔˘˗ ˛˦˧ ˧ ˦ ˠ˔ ˦˔˜˦ ˔˦ ʶ˩˜˗ ˦˧ˣˣ˘˗ ˗˜˚˛ ˦˔˜˜˚˘˧˜˥˘ʡ ˇ˛˔˧ ˔˦ ˨˧˜ ʶ˜ˤ˨˘ ˃˥˧˦ˆ˔˜˜˚ ˛˦˧˘˗ ʾ˘˧ ˆ˖˛˦
ˆ˔˜˜˚ ʴ˦˦˖˜˔˧˜ ˙˥ ˧˛˘˜˥ Ѓ˥˦˧ ˗˔ ˧˛˘ ˔˧˘˥ ˩˘˥˞˘˗ ˕ ʷ˩˘˥ ˖˜˙˙˦ ˔˗ ˖˔˦˧˘ʡ ˀ˔ ˚ʠ˧˜ˠ˘ ˥˘˦˜˗˘˧˦ ˘˥˘˛˔ˣˣ ˧ ˦˘˘ ˧˛˘ ˦˔˜˦ ˔˚˔˜ ˔˦ ˜˧ ˔˦ ˔ ˥˘ˠ˜˗˘˥ ˙˛ ˧˛˘˛˔˥˕˨˥ ˞˘˗ ˜ ˧˛˘ ʤʣ˦ ʛ˔˕˩˘ ˘˙˧ ˛˘ ˖˨˕ ˦˔˜˜˚ ˔˦ ˔ ˙˔ˠ˜˜˔˥ ˦˜˚˛˧ʡ
RYA BOATING QUIZ ANSWERS
1. No, you should zoom in. Details including spot depths and off-lying rocks may not show if the chart is zoomed out. Your plan should indicate the zoom level at various points in the passage. 2. Because a single bearing on the bow may indicate she’s moving ahead but, because of her length, the stern bearing may still be steady. 3. An overtaking vessel always keeps clear and can only resume its course once ‘past and clear’. But bear in mind your duty is to avoid impeding the passage of a ship restricted to a narrow channel. An overtaking vessel may pass either side. 4. An echosounder may indicate a falsely large depth if the bottom is deep mud or disturbed water, such as the wake of a ship. Also, layers of differing salinity or temperature can affect accuracy. 5. Angle of Vanishing Stability, which is the point where a vessel that is heeling will no longer have a righting force to bring it upright. Beyond the AVS vessels will actively capsize. In most yachts AVS is over 100 degrees. 6. The rate at which air cools with height. 7. In a depression, the point where the cold, warm and occluded fronts meet. 8. A quick bearing is unlikely to be precise and vice versa. The longer you take to fix a bearing the further you will travel between bearings so the cocked hat will be larger. 9. An echosounder is a specific use of sonar to
establish depth only. Sonar can be used more widely, including for navigation and fish-finding. 10. Once, in 1908. There were three classes, five entrants and three finishers. The UK won two golds and France one. One boat ran aground, one nearly sank; the sport was quietly dropped.
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rya.org.uk SUMMER 2025
Slender sea
Up until the 18th century the English Channel was mostly referred to as the Narrow Sea – a collective term for the Channel and North Sea.
10 rivers are the source of
90 percent of worldwide ocean debris.
458 metres was the length of the
longest ship ever built, the oil tanker Seawise Giant.
Photos: Cinque Ports Sailing, Paul Wells
Photo: Alamy/Getty
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