Advanced Diver Flashcards
Describe the content of the AD course.
4 lectures
2 dry practical lessons
2 OW lessons
20 dives in a range of conditions
What is the rule of twelths?
Divide tidal range by 12
Each hour after LW, add twelths - 1,2,3,3,2,1
So you know at 4 hours after LW, tide height is LW+ 9 twelths
How do you use a tidal curve?
Draw diagonal line between LW height and HW height
On tidal curve, draw up from time after LW, stop when you hit curve, draw left til you hit diagonal line, draw up til you hit HW height
What are the 2 main factors generating weather?
Temperature
Pressure
What pressure is warm air?
Low pressure because less dense
Describe pressure bands around Earth.
Equator = 0’ = low pressure
30’ above and below = high pressure
Next 30’ N and S (so 60’ N + S) is low pressure
Describe the effect of sideways rotation of Earth.
Get prevailing winds North 60'+ = polar winds N30-60' = westerlies N0-30' = North east trades S0-30' = South east trades S30-60' = Westerlies S 60'+ = Polar
Describe high pressure centres.
Anticyclone (clockwise)
Describe low pressure centres.
Cyclone or depression (anticlockwise)
What are isobars?
Places of equal pressure that are joined by lines
Wind blows at angles across isobars
What direction does wind blow across isobars?
Inwards towards low pressure
Outwards away from high pressure
What is a front?
Boundary between 2 masses of air with different temperatures and humidity
What are the main fronts?
Polar front (60’ N or S)
What is a cold front?
Depicted with a triangled line
Cold front pushes under warm front, forcing warm front to rise
Pressure rises
Heavy bands of rain at first and then clear skies
What is a warm front?
Depicted with a semi-circle line
Warm front pushes over and across cold front - cirrus clouds formed first
Then as warm front pushes further, heavy rain clouds form
Pressure falls
What are the types of cloud?
(High) Cirrus = detached white filament clouds - show a warm front is coming
(Mid) Nimbus = continuous rain cloud - thick and grey
(Low) Stratus = transparent veil like clouds
(Low) Cumulus = detached, dense clouds with sharp outlines
Force 0-3
0: 0-1 kn, calm, sea is mirror like, 0m waves
1: 1-3 kn, light air, sea has ripples, 0m waves
2: 4-6 kn, light breeze, small wavelets, 0.1m waves
3: 7-10 kn, gentle breeze, large wavelets, 0.4m waves
Force 4-6
4: 11-16 kn, moderate breeze, small waves, 1m waves
5: 17-21 kn, fresh breeze, moderate waves, 2m waves
6: 22-27 kn, strong breeze, rough, 3m waves
Force 7-9
7: 28-33 kn, near gale, very rough, 4m waves
8: 34-40 kn, gale, high waves, 5.5m waves
9: 41-47 kn, severe gale, very high waves, 7m waves
Force 10-12
10: 48-55 kn, storm, very high waves, 9m
11: 56-63 kn, violent storm, phenomenal waves, 11m
12: 64+ kn, hurricane, phenomenal, 14m
Describe on-shore winds.
During day, land is warmer
Air over land warms and rises, travels out to see, condenses and blows on shore
Describe off-shore winds.
At night, sea is warmer so air over sea rises and condenses over land
Wind is from land to sea
Time scale terminology in weather forecasts.
Imminent = within 6 hours Soon = between 6-12 hours Later = after 12 hours
Visibility terminology in weather forecasts.
Good = >5nm
moderate = 2-5 nm
Poor = 1000m-2 nm
Fog - <1100m
Pressure systems speed of movement terminology in weather forecasts.
Slowly = up to 15kn Steadily = 15-25kn Rather quickly = 25-35kn Rapidly = 35-45kn Very rapidly = >45kn
What is a decompression lazy shot?
Decompression line attached to main line with karabimer
Has large buoy (min 25L), robust line (at least 7mm), small weight to hold down lazy shot
Requires logging system and for all to return to shot
What is a decompression trapeze?
Solid bars at decompression stop depths supported by 2 weights lazy shots
Requires a logging system and requires all to return to shot
What are the pros and cons of a full face mask?
Secure breathing supply, insulation from cold, alternative gas supplies, communication
Mask malfunction, reg sharing, CO2 build up
What are lateral marks?
Indicate a channel where boat is safe to go down
Red port can shaped buoys
Green starboard cone shaped buoys
Describe the cardinal marks.
N: 2 triangles on top of each other, black on top of yellow
E: diamond shape out of 2 triangles, black yellow black
S: 2 triangles upside dow, yellow on black
W: 2 triangles pointing inwards, yellow black yellow
What do safe water marks look like?
Red and white striped buoys
What do isolated danger marks look like?
Black red black buoys with 2 circles on top
Right of way at sea?
Alter course to starboard to pass on port side of each other
Power gives way to sail
Give way to larger vessels
What are the whistle signals?
1 short blast: altering course to starboard
2 short blasts: altering course to port
3 short blasts: operating stern propulsion
5 rapid blasts: fail to understand your intentions or am in doubt about ability to avoid collision
What does an increase in ambient pressure do to the partial pressure of each gas?
Increases
Eg 10m = 2 bar
So O2 is 0.42
How can you resolve nitrogen narcosis?
Focus on a task Acclimatisation Being mentally and physically fit Well hydrated Right equipment Ascend to shallower depth
What bar does CO2 toxicity occur at and when do we get it?
Levels 0.05 bar above normal = toxic
Levels 0.1 bar above normal = lethal
Hypercapnia - from not exhaling fully, rapid/ shallow breathing, breath holding
Faulty regulator
Incorrect procedures eg full face masks, rebreathers
Symptoms of CO2 toxicity?
Increased rate and depth of breathing
Headache
SOB
Confusion, loss of consciousness
Resolution of CO2 toxicity?
Stop any exertion and relax
Breathe normally
Abort dive
O2 first aid
What jobs need to be done in managing an incident?
Remove casualty from danger Prepare O2 Contact emergency services Consult pt/ buddy for details Note timings Monitor pt and buddy RB + BLS Isolate dive equipment
