When you ride your bike, what might be a good speed? Let’s say you bike at 5 mph. How far will you go in one hour? Answer: 5 miles. To visualize how far 5 miles is, use landmarks such as stores or parks that are located 5 miles from your school.
We don’t typically discuss speed in terms of feet per second. Is 5 feet per second fast or slow? To make this more relatable, let’s convert feet to miles and seconds to hours. Remember, there are 5,280 feet in one mile, 60 seconds in one minute, and 60 minutes in one hour. Here’s how it works:
If we’re driving in a car, we can estimate our speed by dividing the distance by time. For instance, if we know the distance between utility poles is 125 feet and it takes 2 seconds to travel between them, our speed would be:
To find out how fast the canoe is moving, we time how long it takes an object in the water to go from the front to the back. It’s not always easy to tell how far we’ve gone, so we use things like bubbles or even orange peels to help. When these things pass the front, we start counting seconds until they pass the back, and we write down that time.
Now that we know how long the canoe is and how long it took to cover that distance, we can figure out the speed. Speed is just how far we traveled divided by the time it took. This helps us measure the canoe’s speed accurately, even without usual markers in the vast ocean.
As Hōkūleʻa sails, the crew spots bubbles in the water and prepares to time the passage. The distance from the front ʻiako (crossbeam) to the back ʻiako is 42 feet, and it took 5 seconds to cover. What is Hōkūleʻa’s speed? In the ocean, speed is commonly measured in knots. One knot is defined as one nautical mile per hour. One nautical mile is approximately 6,076 feet.
Now that you know how to find Hōkūleʻa’s speed, you might wonder if it’s a lot of work every time. But here’s the trick: the canoe’s length and the conversions we use for distance and time stay the same. So, if we figure out everything except the time (which can vary), we’ll get a special number we’ll call the magic speed number. When we divide this number by the time in seconds, we’ll get Hōkūleʻa’s speed in knots for any time.
Combining the steps from the example into one line and omitting the specific time (5 seconds), we get the following expression for our magic speed number:
only works if the distance between ʻiako is 42 ft. If you are on a canoe with a different length, you will need to calculate a new number. You can obtain that number by replacing 42 feet in the previous example with the length of your canoe.
Choose one person to be the front of the canoe and stand at the front. Everyone else stands behind, keeping a one arm’s length distance between each other. Make sure to keep this distance the same throughout.
