Many boats are made from fiberglass and resin materials because this material is extremely water-resistant.  Water generally does not hurt them.  Alternatively, wood is susceptible to rot, and boats that are completely made of wood are rare.

Fiberglass boat manufacturers have continued to use wood materials in the construction of their boats, especially for structural components such as stringers and decks.  This can lead to problems when the wood gets wet and begins to rot.

Boats lose their overall structural rigidity as the wood loses its physical strength properties due to the rotten wood.

Coating the wood with resin and gelcoat will help to slow the water intrusion.  Keeping the water from entering the boat is the best way to prevent the wood from getting rotten.