Last month I described how to estimate wave height when in a canoe or kayak, but after listening to some descriptions of the “six” foot waves that some kayakers paddled through, I thought a visual aid would be helpful in understanding the height of waves. I’ve built a little diagram showing a 17′ kayak, and a stick-kayaker in different size waves.

The kayaker is 36″ tall from the baseline of the kayak. The waterline is shown in red. The size of a wave when described in feet is the wave height. The lowest wave in this diagram is two feet. The next two waves are three and four feet. The largest wave in the diagram is a six foot wave.

I wrote in the last article:

In the excellent Sea Kayak: A Manual for Intermediate and Advanced Sea Kayakers, Gordon Brown lists a nice standard rule for sea kayakers and canoeists, “If you have a distant horizon the waves are less than one metere. If your horizon is the crest of the wave immediately in front of you, the waves are over a metere.”

Using this rule, you’ll know that if you can see the horizon, the waves were less than 3″². If you can’t, they were over 3″². To refine the rule further, when under 3″² if you loss sight of just your partner’s boat when they’re in the trough of the wave, then the waves are 1″². If you lose sight of your partner’s shoulders and just their head is visible above the crests of the waves, then the waves are 2″².

Estimating wave height on overhead waves is much harder. To get a reference sit on the floor in the kitchen and look to the top of the refrigerator. Most refrigerators are 6″² tall, so if the wave looks like a refrigerator coming at you, then it’s probably 6″² tall.

Remember when in a kayak, the waves always look bigger than they are.

Other Resources

• Waves and beaches: The dynamics of the ocean surface: This is one of the best subjects on waves. If you can find it, buy it!