The choice of materials for the construction and fitting out of boats is essential. Some of them risk, by their heaviness, to destabilize the boat or may prove to be inappropriate due to the movements and pressures undergone (risk of cracks or loosening) or their sensitivity to humidity (untreated wood, metals that oxidize quickly). They must also be insensitive to vermin and fungi and have a good fire resistance. As for the interior fittings, they should avoid tall furniture and take into account the body roll to which any boat is subjected to choose, fix and fill the furniture.