I am altering my course to port
IALA, Ice, Idlers, Impeller, Impress, Inboard, Inboard-outboard, Inflatable boat, Inhaul, Inglefield clip, Inmarsat, Inshore, Instrument, Insurance, Intake, Intertidal zone, Inverter, Inwale, Iron, Irons, in, Iron topsail, Iron wind, IRPCS, Island, Isobar, Isolated danger mark, Isophase, Isthmus
n Frozen water.
Pure water (with no solutes) freezes at 0°Centigrade. Sea water freezes at about -2°C, depending on the amount of dissolved salt.
Ice is less dense than water, and so it floats on the surface.
Being less dense ice occupies more space than the same weight of water: it expands as it freezes and tends to burst the pipes in which it flowed.
n An acronym (ICE) for Internal Combustion Engine.
A rotor or blade in a turbine or pump. The engines (including outboard engines) of yachts and power boats have impellers which drive cooling water through the engine. The impeller is often made of rubber which perishes and disintegrates over time and needs to be changed.
v To compel someone by force to join the Navy.
It doesn't happen anymore.
v To do something which causes other people to admire one.
adj Describing the inside of a ship.
An outboard engine, together with its gearbox, shaft and propeller, is entirely outside the boat, usually mounted on the transom with the engine high and the propeller immersed in the water. The entire unit can be steered: it can also be removed from the boat.
An inboard-outboard arrangement has the engine entirely within the boat. The shaft emerges from the transom well above the waterline and enters an outboard gearbox with a vertical shaft to the propeller below the waterline. The vertical shaft and the propeller can be steered in much the same way as an outboard engine.
A line used to haul something in. A jib-boom extends the bowsprit, and can be hauled in alongside the 'sprit when not in use. The tack of a jib, or flying jib, may be attached to a traveller on the bowsprit and can be hauled in toward the stem to reef or furl the sail.
An international corporation which regulates and provides satellite communication (including 'phones).
The word has become generic for satellite telephones.
Close to the shore, within the national boundary or 12 mile limit.
n A device for measuring. The word implies a degree of manual control of the instrument and dexterity by the operator; a gauge requires no manual control or dexterity (although the gauges on an aircraft are known as instruments).
A rule measures short distances (millimetres to metres).
A micrometer measures short distances very accurately.
Pens and pencils are often known as writing instruments.
n A device for making music.
n A legal document.
A contract of indemnity.
The insurer agrees to pay for the total or partial loss of a vessel, or damage to other vessels or people under certain specified conditions.
If your uninsured vessel causes damage or loss of life you might be sued for damages amounting to thousands or millions. If your vessel is insured, the insurer agrees to pay the damages provided the specified conditions have been met.
A fitting in the side of a power vessel, well above the waterline, for drawing in large amounts of air for the engines.
International Date Line
Because the earth rotates from West to East, the sun appears to rise in the East and cross the sky toward the West. When the sun is overhead the Greenwich meridian it is midday (say, Tuesday) in Greenwich and midnight at the IDL. As the sun continues to move West a new day (Wednesday) starts at the IDL and progresses Westward. When the sun becomes overhead the IDL it is midday Wednesday at the IDL and midnight Wednesday at Greenwich. When the sun is again overhead Greenwich it is midday Wednesday at Greenwich and a new day (Thursday) starts at the IDL.
Voyagers travelling Eastward across the IDL appear to lose a day by moving immediately into tomorrow.
Voyagers travelling Westward across the IDL appear to gain a day by moving immediately into yesterday.
A number of Pacific Island states have preferred to be in either yesterday or tomorrow, and the IDL has been moved to accommodate their wishes: it is now a convoluted zig-zag line up to two time zones from the meridian at 180°East and West.
The land between High Water and Low Water.
A mechanism used to change Direct Current (from a battery) into Alternating Current suitable for powering equipment.
Iron expands as it rusts, and nails become loose in the planking. The oxide encourages rot in the timbers, which become iron-sick.
Iron is sometimes used as ballast for sailing vessels. Its advantage over lead is that it is cheaper: its disadvantages are that it rusts and makes a mess in the bilges; it is less dense than lead and so occupies more space for the same weight.
Iron topsail, Iron wind
The Regulations are not necessarily easy to read, so attempts have been made to interpret, summarise and simplify them. Any such change of words necessarily changes the meaning and is dangerous.
A body of land smaller than a continent, surrounded by water.
An island is not necessarily one country. The mainland island of Britain is part of one nation (the United Kingdom of Great Britain and Northern Ireland) but has several countries (England, Scotland and Wales). The island of Ireland has one nation (The Republic of Ireland) and part of another nation (Northern Ireland is part of the UK).
Continuous lines, drawn on a chart, linking points of equal atmospheric pressure. Where the atmospheric pressure is measured in millibars, isobars are drawn on a synoptic chart at intervals of 4 millibars.
If the Earth were not rotating, air (winds) would move directly from the high pressure region to the low pressure region and the two would tend to become equal at about 1013.25 millibars: with the same atmospheric pressure everywhere there would be no isobars.
But, with some parts of the Earth being warmer than others, warmer, less dense air rises. The rotation of the Earth, and the resulting Coriolis force, causes air (wind) to rotate anticlockwise (North of the Equator) within rising air masses around low pressure centres. The winds (moving air) tend to follow the isobars, but angled about 15° inward to fill the low pressure.
Where there is a great difference in atmospheric pressure over a short distance (at the S tip of Greenland on this chart) the isobars are closer together and the wind, attempting to move from high to low, is stronger.
The colder, more dense air falling onto the British Isles and France (on this chart) rotates clockwise, following the isobars but angled about 15° outward to fill the lows; the pressure gradient is smaller, and so the isobars are further apart and the winds are lighter.
'Warmer' and 'colder' are relative terms. The 'colder' air mass falling onto France and the British Isles might be at 25°C, but colder than surrounding air masses: the 'warmer' air rising to the SE of Greenland might be at 15° to 20°C, but warmer than the surrounding air masses.
Iso.5s means that the light is on for 2.5 seconds, off for 2.5 seconds, in each 5 second period.
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