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Compass Story

Available as an Adobe PDF file.
This is my fictional version of the true story that you find at the end of this page. You may use either story.

Read this to the students.

There once was a ship named the Dependable. She belonged to a man in his mid forties. The man always did coastal cruising. That is he always sailed the Dependable close to shore. He did not need to use charts because he had grown up and learned to sail in the same area, and he knew all the shallows and deeps.

One night a few his friends were on board with him for a party. They got to talking about old times. Looking back on it none of them could say for sure whose idea it had been, but before the sunrise came they had decided to sail from California to Australia, across the Pacific Ocean.

They bought all the supplies they needed. They stocked up on things like food, spare parts (even though not a single one of them had ever turned a wrench), and charts. It took them a month to get ready to go, but finally the day came. They set sail.

Things went great for days. The weather was nice and the constant tradewinds provided a quick passage for the Dependable and it's crew of four. The crew was settling into a routine.

Their routine did not, however, include plotting a line on a chart. They would look at the GPS and it would tell them about where they were. That was good enough for this crew. They could also tell the GPS what their final goal was, and it would tell them what course to steer. You see they had found that taking compass readings was easy, but they didn't understand how to do the corrections to the readings. Every time they tried to plot where they were on the chart it never agreed with the GPS. But that was okay because as long as the GPS was working they weren't lost.

One night they had the auto pilot set on exactly the course the GPS had set for them. They were moving out under a steady wind at 5 knots. There was nothing in sight for as far as they could see, except water and sky. The crew left the deck of the Dependable and went below to play cards and cook diner.

Without any warning the Dependable came to a sudden and violent stop. The crew was thrown forward in a large pile on top of each other. Water started to pour in around their knees and hands as they scrambled up on deck. As the Dependable sank, they swam for the shore of a small island in the South Pacific.

What went wrong?

The GPS doesn't tell you if you are over land. They didn't know there was an island in the way, because they were not plotting their progress on a chart.

Here is the true version of this story as retrieved from a page about ship wrecks (http://home.earthlink.net/).

Rabba Abba - US boat - about 44 ft, fiberglass. Tied up beside us on the wall in Papeete. They left Tahitit for American Samoa. The story we later heard was that they had set a GPS waypoint at Pago Pago and sailed a rhumb line, watching the cross track error. Unfortunately, they apparently didn't check a chart to find out that Rose Island was in their rhumb line. They hit the barrier reef, walked ashore and set off their 406 EPIRB. A freighter picked them up the next day. We saw them again later in NZ, buying another boat with the insurance money.

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