Continuation of the notes for the final exam

Discussion:

Voyaging - Keynote pdf
Navigating - Keynote pdf
Weather Forecasting - Keynote pdf

Voyaging

Each sailing canoe had a navigator whose job was to read the signs in the clouds, wind, current, floating debris, birds, sun, and stars.

Sailed generally during the calmer season, when the weather in the middle of the ocean is consistent.
Some scientists think that the weather several hundred years ago was even calmer than it is today.

Hawaiians rode out storms in the lee of island or dropped sail and rode out the storm, as water soaked pandanus sails tore easily.
Additionally, they had to bail out the canoes during the storm.
They paddled in times of calm seas, especially important is the Doldrums at the equator.

The Doldrums are a region of low atmospheric pressure at the equator, where the winds are weak and variable.

Navigating

Navigators used many techniques to guide a canoe.

They would line up features, such as two mountaintops, to set sail.
Generally started in daylight to avoid reefs, but night was best for sailing as they used the stars to navigate.

Knew the positions on the horizon of over 150 rising and setting stars. Pointed canoe in the direction of the certain stars that lead to the desired destination.

They also used stars to determine when they had traveled far enough. Certain stars passed directly above certain island groups:

• 'A'a is the zenith star for Tahiti
• Hokule'a is the zenith star for Hawaii

The angle between the steered course and the canoe's wake (whitewater) showed the navigator how much leeway, or drift due to strong winds and currents, the canoe had. The navigators steered up wind to compensate for drift.
Had to compensate by sailing slightly to the east when sailing into the Northeast Trade Winds.

Also had to compensate for the North and South Pacific Equatorial Currents, and the Equatorial Counter Current.

Additionally, navigators used swell to navigate.
The winds, and thus the swell, would come from certain directions.

Weather Forecasting

Wind

To determine wind direction:

• Turn to face the wind so that the pressure is even on both cheeks.
• Watch the direction of that the clouds travel
• Watch the leaves on the trees
• Watch the ripples on the ocean

Swell

A diminishing swell means the wind is weakening.

Rounder, longer well means the strong wind is farther away, whereas shorter, steeper swell means the wind is close.

Clouds

Cloud tell of coming weather, navigators use the shape, height, color, and sequence of clouds to forecast weather.

Generally the lower the clouds, the more likely that bad weather is coming.

Color of Atmosphere

Red skies at sunrise or sunset indicate humidity in the air.
Red skies to the east mean coming rain or stormy weather.

Light Around Celestial Bodies

A halo around the moon is a sign of rain.
The halo is caused by the moon shining through ice crystals of moisture-laden clouds.
If the halo is a tight fit, the rain is still far off, if the halo is large, rain is near.

Twinkling stars indicate that the atmosphere is unstable and turbulent, a sign of stormy weather.

When the dark side of the moon can be seen, the air is clear and stable, a sign of good weather.

Smells

Rising humidity and the associated low atmospheric pressure enhances smells.
Thus stronger smells may be a sign of rain or stormy weather approaching.

Animal Behavior

Hawaiian proverbs suggest that sea birds hunt during good weather and seek shelter from stormy weather.

An other proverb says that dolphins in harbors means storms

The notes for the final exam are complete