Preventing sea sickness?

Familiarity can certainly reduce the likelihood of sea sickness, as your body can get used to it.

The usual problem is the swell - which you just don't get on lakes. Out on the ocean you have no stationary frame of reference so your brain starts to believe the boat is stationary. As it is actually moving, this confuses your brain and causes sickness.

Different areas have different bad seasons and some seas are worse than others but generally the bigger the expanse of water the bigger the waves and swell.

If you are actually wanting a cure, have a read of this question over on Go Outdoors.

Sea sickness can also differ from sea to sea, from ocean to ocean and from boat to boat. I am not so sure if familiarity helps. I know someone who has been sailing the seas for years, but when he got on to the North sea, he got sea sick. Being raised in a landlocked area is not necessarily relevant. Furthermore the type of boat has an influence as well. I am always amazed how quickly people "cure" from sea sickness. Sometimes it is as fast as turning a corner or cape. It is a complex mix of boattype, currents, winds, shallowness, etc.

The main advice preventing sea sickness is that once you have it get on deck and stare to the horizon! The worst thing you can do is stay in your cabin. This is usually what you want to do when being sea sick, but it can make things worse.

Sea sickness feeling really depends on the size of the boat.

For instance : during a cruise in January, we had a stopover at Cozumel island; since part of the proposed excursions were on mainland Mexico, many had to board a small catamaran ferry for the crossing; and the sea was not forgiving on that day.

Many guys who were fine on the cruise ship (a big NCL one) were sick on this short 20-minute crossing. Interestingly, the small boat had 2 decks. I had the reflex to sit on the upper, open-air one; most passengers here had no sickness. Later, I checked the lower, enclosed deck; sickness arose so quickly there that crew members were giving barf bags away.

Bigger vessels are more stable, and being in open-air also helps.

Sea sickness happens to everyone and sometimes in very unexpected situations. I've seen brave and experienced sailors getting sea sick, so it's not all about experience, though it helps.

I can give you a few advices:

1. try to get fresh air / if you're inside the boat get outside.
2. look at the horizon line. Looking at a more stable, distant point helps
3. try to distract yourself. Don't focus on the sea sickness. Do something (it helps me). Specially if it involves some degree of attention / responsibility.
4. If you're doing a task and start feeling sea sick stop doing it if possible (don't let it grow). Try point 1 and 2
5. If you have control over the boat / ship steering, and it's safe, put the boat (bow and stern) in the same direction of the waves. (If possible sail in the same direction of the waves. This will make going up and down the wave softer.)

Try to avoid having your stomach empty. It's more painful if you get to such a state. Eat soft flavoured food. Avoid strong flavours and smells.

There are also pills that help to avoid sea sickness. They work but it's not 100% fail safe. (it should be easy to find them in any pharmacy).

I've heard it explained on the MythBusters tv show that it's that you being stationary in relation to what you see with your eyes, and perhaps your innner ear telling you that you are moving. Only thing that seemed to help in their tests was eating ginger.