Composites are widely used for the repair of deteriorated and damaged structures. For example, the rehabilitation of bridges and buildings and the seismic retrofit of columns using composite reinforcements are widespread in the US, Canada, Europe and Japan. It was shown that adhesive bonding of structural composite reinforcement is the most suitable technique. The bonding offers excellent strength and fatigue properties due to the continuous nature of the connection. This arrangement gives a uniform stress distribution over the entire bonded area. Although the bonding technology is becoming increasingly popular, this method of joining is still largely unexplored in the shipbuilding industry. Structural defects on ships, like cracks, are typically repaired by welding. However, welding has many disadvantages as the long operational time, hot-work, and shutdown of parts of the boat can cause very expensive production delays or weight increases. A repair with a composite patch can be used as an alternative without any fire hazard and is a lightweight solution. The patch is bonded over the defect and restores the integrity of the original structure. The design of patch repairs is more complex than the design of a traditional repair by means of welded joints, due to the presence of three different materials (steel, adhesive and composite) and the influence of several parameters (patch dimensions, shape) on the repair performance. This article reports some results of the patch design of several large-scale marine details which have been manufactured, artificially cracked and tested within the test campaign of Co-Patch.