Greece Category A Theory flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Chart datum

The reference level from which depths and drying heights are measured, normally Lowest Astronomical Tide (LAT). Actual depth = charted sounding + height of tide.

Three-point fix

A position fix using bearings to three charted objects. Position lines crossing at about 120 degrees give the smallest cocked hat and the most reliable fix.

Overtaking vessel

Under COLREG Rule 13, any vessel overtaking another is the give-way vessel until finally past and clear, regardless of vessel type or propulsion.

Head-on situation

Under Rule 14, two power-driven vessels meeting head-on both alter course to starboard and pass port-to-port. Neither vessel has right of way.

Buys Ballot's law

In the Northern Hemisphere, with your back to the wind, low pressure lies to your left. In the Southern Hemisphere, it lies to your right.

Beaufort force 6

A strong breeze with wind speed of 22-27 knots. Expect large waves, whitecaps and some spray; reduce sail early in these conditions.

Spring line

A mooring line led fore and aft to prevent a vessel from moving along the quay. It is used with bow and stern lines to hold position.

Man overboard procedure

Shout 'man overboard', throw a lifebuoy, press MOB on GPS, turn toward the casualty, approach from downwind with engine in neutral near the person.

SOLAS V assistance duty

The master must render assistance to persons in distress at sea when able to do so without serious danger to the vessel and those on board.

MARPOL Annex V

Prohibits disposal of plastics and restricts garbage discharge at sea. Waste must be retained on board and landed at shore reception facilities.

Fire triangle

The three elements needed for combustion: heat, fuel and oxygen. Fire is extinguished by cooling, smothering or removing the fuel.

MAYDAY distress call

Spoken on VHF Channel 16 or sent by DSC on Channel 70. State position, nature of distress, assistance required and persons on board.

Four-stroke diesel cycle

The four strokes are intake, compression, power (combustion) and exhaust. Fuel is injected near the end of compression and ignites from heat.

Sacrificial anode

A zinc or aluminium block fitted to the shaft, rudder or hull to corrode in place of the vessel's metal parts. Replace when about half consumed.

Rule of twelfths

A method to estimate tidal height between low and high water: 1/12, 2/12, 3/12, 3/12, 2/12, 1/12 of the range in each successive hour.

Estimated position

A dead-reckoning position adjusted for the tidal stream and leeway. It is plotted from course and speed through the water plus the tidal vector.

Pressure gradient

The spacing of isobars. Closely spaced isobars indicate a steep pressure gradient and stronger wind; widely spaced isobars indicate lighter wind.

Meltemi wind

A strong northerly wind that blows in the Aegean Sea in summer. It can reach gale force and affects sailing and anchoring plans.

Mediterranean mooring

A mooring method where the bow is anchored or secured to the quay and the stern is kept clear. Fenders protect both sides of the hull.

Reefing

Reducing sail area by tying in reef points or rolling the sail. Reef the main before the jib and reef early as wind rises.

Liminarchio

The Greek port authority. The skipper must report accidents, pollution and dangerous cargo incidents to it as soon as practicable.

Collision liability

Liability for a collision is apportioned by fault. Both vessels can be held partly to blame, including for failure to act in time.

EPIRB

An emergency position-indicating radio beacon transmitting on 406 MHz to satellites. It must be registered and tested regularly and taken when abandoning ship.

SART

A search and rescue transponder that responds on 9 GHz radar, showing a series of dots on the rescuer's radar screen. It helps locate survivors.

Diesel bug

Microbial growth in diesel fuel that clogs filters and causes engine failure. Use a biocide, keep tanks full and polish the fuel.

Battery isolator

A switch or device that separates the starting battery from the house bank, preventing the start battery from being drained by domestic loads.

Running fix

A position fix using two position lines taken at different times. The earlier line is transferred along the course and distance made good.

Traffic separation scheme

Under COLREG Rule 10, vessels should cross lanes at right angles and avoid the separation zone. Keep to the appropriate lane direction.

Cold front passage

A cold front brings squalls, heavy rain, a sharp wind veer and a temperature drop. Expect rapid changes and reduce sail early.

Bowline knot

A knot forming a fixed loop that will not jam under load. It is used for securing a line around an object or to a person.

MARPOL Annex I

Prohibits discharge of oil or oily mixtures into the sea. The Mediterranean is a special area with stricter discharge restrictions.

Hypothermia treatment

Recover the casualty horizontally, insulate and warm slowly. Do not rub the limbs or give alcohol; start CPR if not breathing.