What Is Seasickness?
Seasickness is primarily a form of motion sickness, generally attributed to spending time on a craft on the water.
Why Do Some People Get Seasick?
Were it not for certain control centers in our brains that maintain our equilibrium, we would constantly topple over. To determine which way is up, down, sideways and points in between, the brain takes the information relayed to it by our senses, calculates our orientation in space, and informs our muscles how to react so as to keep us upright.
The brain gets most of it's information from our inner ear, which acts as a sort of carpenter's level, but it also uses data transmitted by our eyes, muscles and tendons. On terra firma all goes well because the different sources of information are in agreement.
But at sea, things are not so clear because the movement of the boat mixes up the signals that our brain has to interpret. What our inner ear senses no longer agrees with what our eyes see or muscles feel. We are like an airplane pilot whose eyes tell him one thing while his instruments tell him another.
This is a problem at sea, receiving contradictory information from our senses, the brain may immediately decide to disregard some of the information, in which case we feel fine. But if confusion continues to reign, nervous tension builds up and results in seasickness. Within a few hours, if the brain has still not adapted to the situation, vomiting occurs. This often relieves the nervous tension, hence the temporary relief one can feel.
Vision plays a big part in the way our brains judge orientation. When we are on deck, the movement of the boat sensed by our muscles and inner ears is confirmed by the inclination of the horizon. If we go below, though, our eyes will only be able to judge the boat's motion by what they see in the cabin, while our inner ears continue to sense the boat moving in the waves. This kind of conflict can easily lead to seasickness. It is best to be out on deck. But you mustn't lie motionless in the cockpit; you have to "ride the waves" like a horse back rider going over jumps. That means looking around at the sea so that your brain can anticipate what posture to adopt. It is also a good idea to get up and walk around, if possible. It helps to develop "Sea Legs".
Suffering from seasickness out on the water is extremely miserable and can easily ruin a trip. Prevention is usually better than cure and to assist, we have all sorts of products to try and tackle the problem.