-- This is a real story. --

Exploding waves

In a stormy sea called Roaring Forties, big waves attacked Aomi one after another.
big wave South Atlantic

While crossing the rough sea of life, unexpected accidents, bad luck, deadly illnesses, and disasters can sometimes make you feel, "It can't be true!"

The case I had experienced five years after leaving Japan was, no doubt, one of them.


A small single-handed sailboat Aomi left Buenos Aires, the capital of Argentina, and was sailing down the South Atlantic towards Antarctica.

When the sound of wind suddenly got stronger just after sunset, waves on the black water began to grow in height quickly. Their peaks, soon, started to roll, collapse and attack Aomi one after another.

"Don't get heavier!" I shouted.

I go into the cabin, take the boots and oilskin off, and lie down in the berth of violently shaking Aomi.

After midnight, a crack like breaking  giant glass has sounded in the dark. At the same time, the impact of the wave throws my body into the air. I feel for the switchboard with my hands in a hurry and turn on the cabin light.

I have regained the sense of up-and-down, and quickly understood the situation.

Aomi, capsized by the wave, has turned back to normal by the balancing effect of the heavy ballast attached to the bottom. Though running like an arrow, she seems to have stopped and is rolling heavily.

"That means...... No, I don't think that's gonna happen," I talked to myself.

I open the sliding hatch in a hurry, grasp a flashlight and turn it upwards.

There is no mast! The mast has gone. What should never have happened have become a reality, though I have had a belief that I am not such a beginner or a fool.

"This ends my entire dream. Everything has gone wrong."

For more than one year in Buenos Aires, I had prepared and modified Aomi for ice and coldness, and worked hard as a private teacher to make money just for going to Antarctica. What were they for? The power of my whole body goes out.

the route to the Antarctic, roaring forties, furious fifties, screaming sixties

By the way, what is the dull sound to hear for the first time, and what is the shock suddenly stops the motion of Aomi shaken by waves?

I open the sliding hatch, get my upper body out in the complete darkness, and turn a flashlight to the water.

"I have never seen such a strange thing. Plants or animals?" I grumbled.

Something, like a pillar with long silvery whiskers or ivy curled around it, is sticking out of the water.

It's the broken upper 3/4 of the mast half submerged, but still connected to the deck with seven stainless wires.

Each time a wave attacks and shakes Aomi, the broken mast in the water hits her body severely. That will make a hole in the hull and sinks Aomi! I put on an oilskin and a safety harness, and come out of the cabin into the spray-filled darkness.


In my early 30s, the accident was the biggest shock in life. I realized that the conviction, "It can't happen to me," was just a belief.

Hints for safe sailing

What you should consider is not only the height of waves. You have to realize the density and destructive power of water, which is more than 800 times bigger than air.

Since we are blown by the wind often but seldom by water, we are unfamiliar with its power.

Ignorance and imprudence may cause a fatal accident at sea.

Translation Assistance Needed


The above is an episode of Aomi in the South Atlantic Ocean. You may think that the title, "Exploding waves," is a bit exaggerated, but it may be suitable because of the reason below.

Grasping the photo opportunity is very difficult, even when you are aiming your camera at the waves. The wave head collapses in an instant, and the next moment, waves cover whole your body. The image of the wave which suddenly crumbles in white, is very close to the dazzling white of an explosion.

big waves in South Atlantic

I took the above photos in the South Atlantic Ocean. Are they frightening to you? The left one might seem more powerful than the right one, but you have to consider the distance.

On a closer look, the wave on the right is beyond the ridge of water. It is more distant but much higher than the wave on the left.

Those photos were taken when Aoim was heading toword the north in the South Atlantic Ocean and then capsized even twice in the same night, lost a small dinghy on deck and got a 1.7m open-crack in the hull. Two years later when sailing for Antarctica, Aomi had overturned again and lost the mast as described above.

Why did Aomi capsize many times in the Southern hemisphere? Why is the southern sea, very rough?


Cape Horn, regarded as the southernmost of South America, had been widely feared as a most dangerous and terrible spot for sailors since the Age of Discovery. Why?

One reason is that the latitude of Cape Horn is as high as nearly 56° S. The southernmost of Africa is located at about 35°S and even Tasmanian Island, south of Australia, is located at about 44°S. You can imagine how high the latitude of Cape Horn is.

Generally, the sea becomes rougher as the latitude increases. Sailing in higher latitude may be harder and more painful. It would be far better to choose a route at lower latitude near the equator.

Again, why were European sailors, in the Age of Discovery, afraid of Cape Horn so much? Is it due to the high latitude?

London in the U.K. is located at 51° N and Oslo in Norway at 60° N. Though their latitudes are as high as that of Cape Horn, why were the European sailors afraid of Cape Horn so much?

There is a significant difference between the Northern and the Southern hemispheres.

land-sea ratio

One is the ratio of land to sea. Though the percentage of land is 40 in the Northern hemisphere, it is only 20 in the Southern hemisphere.

Land works as resistance to wind and prevents wave and swell to grow up. There is little chance for wind and wave to weaken in the Southern hemisphere.

Another factor is the cold of Antarctica. What is the relationship between the coldness and the roughness of the sea?

A cause of wind is the difference in temperature.

wind caused by the temperature difference

At the South Pole, the temperature is much lower than that in the North Pole. The South Pole in summer and the North Pole in winter both have nearly the same temperature.

Consequently, the difference in temperature between the equator and the polar region is always bigger in the Southern hemisphere than that in the Northern hemisphere. That may strengthen the average wind in the Southern hemisphere.

The reason why they were afraid of Cape Horn very much, is not only described above but also the steep triangle waves, shallow seabed, some currents. I might have an opportunity to explain those later.


Why can a sailboat capsize? On which occasion does she overturn or become upside down?

sailboat capsizes with big waves

If there are very high and steep waves like above, it happens readily, but low waves can also cause a capsize.

sailboat and shallow boat capsize in breaking wave

When the stream, caused by a breaking wave, hits a boat with a shallow bottom, she may move parallel to the water and get no damage.

A boat which has a ballast-keel sticking out of the bottom, like a sailboat, may capsize easily because the resistance force to the keel turns her over.

yacht or sailboat capsize
It is very dangerous for a sailboat to run in a side wind when high waves are breaking, because the wave direction and her side are at the right angle.

You might think, "I never do such a stupid thing," but you can't avoid it, because a boat may lose control of itself due to weather-helm, or a breaking wave might hit and turn her side toward the wave.

Particular attention is required when sailing in a following wind with a wind-vane-self-steering system if it is attached to the stern because of its positive-feedback property.

When you are running in the following wind and get an attack of a breaking wave, it may push her stern aside, and turns her side to the wave. During the motion, by the apparent wind caused by that, the wind vane steers not to correct the heading, but to boost the motion.

You can avoid this positive-feedback problem by using an electric autopilot with a compass sensor, or put your wind vane on the midship or the bow!

hand-made wind-vane pendulum and auxiliary rudder

*The episode after the capsize, and the reason why I decided to go to Antarctica, let me tell you later.

Translation Assistance Needed


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