67 Navigation
The following is from http://pvs.kcc.hawaii.edu/ike/hookele/modern_wayfinding.html.
A voyage undertaken using modern wayfinding has three components:
Design a course strategy, which includes a reference course for reaching the vicinity of one’s destination, hopefully upwind, so that the canoe can sail downwind to the destination rather than having to tack into the wind to get there. (Tacking involves sailing back and forth as closely as possible into the wind to make progress against the wind; its very arduous and time-consuming, something to be avoided if at all possible, particularly at the end of a long, difficult voyage.)
During the voyage, holding as closely as possible to the reference course while keeping track of (1) distance and direction traveled; (2) one’s position north and south and east and west of the reference course and (3) the distance and direction to the destination.
Finding land after entering the vicinity of the destination, called a target screen or ‘the box’.
So how is the navigation done — especially component (2) — through thousands of miles of open ocean? You can’t see land. How can you hold closely to the reference course? How can you keep track of distance and direction traveled? How can you even know if you’re going in the right direction if all you can see is blue ocean and blue sky?
By day, the navigators use their deep knowledge of the oceans. Which way do the winds blow? Which way do the prevailing currents move? Clouds in the sky, flotsam in the water, and animal behaviors give them great insight into where land might be, and where they are in relation to it.
By night, they use the stars. In this section, you’ll learn just a tiny fraction of what these master navigators know about the stars.
Think / Pair / Share
Here is a time-lapse picture[1] of the stars in the night sky:
- Describe what you see happening in this picture.
- What can you conclude about how the stars move through the night sky?
- How might that help a navigator find his way?
Star Compass
A fundamental tool for navigators on Hōkūle`a and other voyaging canoes is a star compass. Here’s a picture of Mau Piailug[2] and a star compass[3] he used in his teaching.
The object in the center of the circle represents the canoe. The shells along the outside represent directional points. The idea is to imagine the stars rising up from the horizon in the east, traveling through the night sky, and setting past the horizon in the west. They move like they’re on a sphere surrounding the Earth (it’s called the celestial sphere).
Problem 4
Nainoa Thompson developed a star compass with 32 equidistant points around a circle. (Note this is different than the points in Mau’s star compass pictured above.) You will first try to make a rough sketch of Nainoa’s star compass based on this information.
- Place 32 points around the circle so they are equally spaced.
- The arcs between these equidistant points are called “houses.” You will label each house with