Why did it used to be harder to sail over deep ocean, compared to shallow waters

Question

Why did it used to be harder to sail over deep ocean, compared to shallow waters

In: 152

Answer 1

I am going to disagree with other commenters here and say that in rough conditions it is actually shallow water that you want to avoid. Deep ocean waves can get very large, but are typically swells which are long waves and so not dangerous. When a wave reaches shallow water the front slows down, and so the back of the wave catches up and all the water piles up. Waves entering shallow water get taller and steeper, eventually breaking. You will probably have seen this phenomenon in miniature at any beach. Steeper waves are much more dangerous because they can capsize a vessel.

And this effect is present at any shallowing, there are patches of the Northern Atlantic (and no doubt other seas I am not familiar with) that you might want to avoid for the above reason, despite them being many dozens of metres deep.