Patents
Patents protect the use of ideas. Most countries would not let someone patent an idea after it has been published. So one way to make sure that you can use an idea in the future is to publish it, this way nobody else can patent it.
Most of the patented stuff seasteaders would want to use is things like paints, motors, solar panels, etc that we just will buy.
Patents and ships
"Article 5ter Paris Convention demonstrates a concern to leave the channels of international commerce free from the burdens that would result if vessels had to conform to the patent laws of all nations that the vessel or vehicle visits during its lifetime. Different inventions are likely to be patented in different countries, and the same invention may be patented by different parties in different countries. Article 5ter Paris Convention places foreign-owned means of transport beyond the reach of domestic patentees’ exclusive rights. This prevents the international traffic of goods and persons from being obstructed by seizures at the borders and other measures."
So if we flag our seasteads with some country that is part of this agreement that we don't have to worry about patents outside of the country our seastead is built in (and maybe not even there). There are a number of countries with shipyards where, in the unlikely event that you are caught, the fees for violating patents are very small.
Links
paper about patents and ships/shipyards].
