Figure 1-1. Traditionally, boats were built with a backbone-like keel with ribs defining the shape. This frame of ribs was then covered with planks to make a watertight hull. The frame provided most of the strength. While the planks provided some strength, without the ribs supporting them, they would split. In strip construction a monocoque shell provides both the strength and the watertight hull. The thin outer planks are reinforced across the grain with fiberglass fabric secured and sealed in place with epoxy resin.