Winds/Currents/Tides Flashcards
If you are sailing “Off” the wind, you are on a ________, ________, or ________
Beam reach
Broad reach
Running
Regarding weather reports, what does a “gale warning” mean
Winds speeds:
34-47 knots (39-54 mph)
Waves are the product of ________
Wind (in many cases)
What happens to apparent wind in a “puff”
Apparent wind increases in strength and shifts toward the stern
What does “Running” mean
Sailing with wind directly behind you
What does “Beam Reach” mean
The wind is at a right angle to the boat
Up is short for ________
“Bring her up” means ________
Upwind
Turn toward the wind
What is an anemmeter
An instrument for measuring wind speed
Do we sail to true wind or apparent wind
Apparent wind
-The wind we feel on our face is the same wind the sails feel, thats what you would trim the sails for
What is a “Neap Tide”
When do neap tides occur
Weak tides - small differences between the highs and lows
Twice a month, 7 days after a “spring tide”, and when the sun and moon are at right angles to each other
What does “Broad Reach” mean
Wind blowing slightly in a leeward/downwind direction
or
Sailing between a “Beam Reach” and “Running”
or
Wind blowing between beam and stern
What does “MHW” mean on charts
Mean High Water
The average high water level
Regarding weather reports, what does a “small craft advisory” mean
Wind speeds:
20-33 knots (24-38 mph)
How many tides occur in the Gulf of Mexico
Once a day (diurnal)
-Only one high and one low per day
What does “leeward” mean
Anything downwind
or
The side of the boat furthest from the wind
What is the speed of a current called
Drift
Sailing “Off” the wind means ________
Your course is in a leeward direction (sailing downwind)
What is a “Spring Tide”
When do spring tides occur
Strong tides - large difference between the highs and lows (about 20% more than average)
Twice a month when the moon, sun, and earth are in alignment
What is a “masthead fly”
A wind indicator at the top of the mast
Sailing “On” the wind means ________
Your course is in a windward direction (sailing upwind)
When sailing, current can be determined by
Watching the water move around a fixed object
Regarding weather reports, what does a “storm warning” mean
Winds speeds:
48-63 knots (55-72 mph)
What are “incoming” and “outgoing“ tides called
Incoming - Flood
Outgoing - Ebb
How many minutes are there between tides
Are there any outside factors affecting these times
6 hours and 12 minutes
Yes; local winds and weather
Where do you place “telltales” to determine wind direction
On the shrouds
Over most of the world, tides usually happen how many times a day
Semidiurnal (twice a day)
-two equal highs and lows
What is the easiest and fastest point of sail
Beam Reach
What is the foundation of wind patterns
Differences in temperature between the equator and the poles
-Warm air rising is replaced by colder air
There is also
- Earths eastward rotation
- Areas of high and low pressures
- Land-masses
- Land and sea breezes
If you are sailing “On” the wind, you are either ________ or ________
Close hauled
or
Close reach
What does “MLLW” mean on charts
Mean Lower Low Water
The average height of the lowest low tides
*This is the water depth displayed on charts
How do the physics of sailing change while “Running”
Sails lose aerodynamic lift and act as wind catchers to push the boat
Down is short for ________
“Bring her down” means ________
Downwind
Turn away from the wind
Waves can be manipulated by outside forces. Name some examples
- Currents from rivers
- Narrow passages
- Points of land
- Tides running against the waves
- Shallow underwater ledges
What does “Close Hauled” mean
Sailing as close to the wind as possible
What does “Close Reach” mean
Wind blowing slightly in a windward/upwind direction
or
Sailing between “Close Hauled” and “Beam Reach”
or
Wind blowing between beam and bow
What is a “Land Breeze”
At night, land and the surrounding air cools more rapidly than air over the water
-This causes a wind from land to water
What does “windward” mean
Anything upwind
or
The side of the boat closest to the wind
What is a “Sea Breeze”
At daytime, land and the surrounding air heats up, rises, and is replaced by cooler air from the water
-This causes a wind from water to land
Why is “Running” the slowest course
The faster you go the less apparent wind there is to push you
What causes “tides”
The gravitational pull of the moon and to a lesser extent the sun
What is “True Wind” vs “Apparent Wind”
True wind is wind you feel standing still
Apparent wind is a combination of true wind and the wind created by our moving forward
Can you determine the current if you know the wind direction
Yes; look at the waters surface
Waves/chop = current running against the wind
Smooth/calm = wind and current aligned
Rough looking sea = strong wind blows against the current
