"Structure. The main purpose of the upper or primary deck is structural, and only secondarily to provide weather-tightness and support people and equipment. The deck serves as the lid to the complex box girder which can be identified as the hull. It resists tension, compression, and racking forces." The deck of a boat is the main part for people and resources. It is one of the safest areas of the boat. (Sorry if this aint what you need, this question was a bit unclear.)
