Acceptable Motion

In designing seasteads we need to understand what amount of motion is acceptable.

The basic problem is that your brain is used to being able to tell what vertical is by looking at buildings and things, but on a ship it is not so simple. The conflict between visual cues, your inner ear, and the motion your body feels causes the trouble.

There have been studies working out formulas for what amount of motion causes sea sickness.

In general it seems that after a few hours to a few days people develop "sea legs" and are adapted. If tourists are coming for 1 week visits a few days to adapt takes away a lot of the fun. If a family is moving onto a seastead for good, a few days to adapt is no big deal. Minimizing motion is more important for short term tourism.

There is some uncertainty with regard to the amount of permissible motion; accurate data does exist for transient passengers on ships, however, a strong adaptation to sea-sickness is noted in many places, but nowhere is this adaptation quantified. This is very relevant when considering permanent settlement versus brief visits by tourists.

For permanent settlement, we aim for a maximum of 5% of days which require medication to deal with motion-induced sickness.

Quantative data on adaptation would be most welcome. While data on adaptation is not available, comparisons will be made with the ISO standard for passengers, taking in mind that these are overly pessimistic results as far as permanant residents are concerned.

Stability of Competition

For comparison here is a very stable $4 million yacht. It was designed by the Dashews and is called "Wind Horse". There are many videos on youtube. It has very large active stabilizers. They have also come out with a $2.5 million version. These boats are efficient enough to cover long distances at reasonable speed. The speed keeps pitch to a minimum and the speed lets the active stabilizers just about eliminate roll. If we can be this stable then we are doing well. If the seastead is a shape that is naturally stable so that we don't need speed and active stabilizers we can have a lower cost and run on solar power.