Welcome Walsilvia! Resistance to chemicals, including all types of gases, odors, oils, water
, etc. is indeed a big issue in shipbuilding. The issues are, in general, very specific to a particular problem. One problem is to keep water
on the outside of a boat of course. Some materials are more impervious than others. Same with solvents, oils, etc. Holding tank
odors are a big concern. Some plastics are terrible at isolating odors in tanks
and hoses. Others are very good. Some metals are not good in some places in engines.
Some barriers require unique approaches. The best way to protect exterior steel
and many other metals is actually to provide less anodic materials that are sacrificial. The protection is provided by having another metal that uses up the harmful chemicals, in essence, diluting them so that the surrounding metals have more "protection". Paint
is one solution but is often not enough, so zincs are placed on the outside of ships to provide additional protection. These have to be replaced as they are eaten up by the attacking chemicals. Etc, etc, etc.
The number of issues, and the complexities of the issues, and the varying opinions as to the "best" solutions would take you years of study. You'll have to be much more specific to gain any useful information.