Parts of a Ship

Application of Strakes and Platens

The exterior (hull) of large ocean going vessels is made of long strips of steel plate, often called strakes. Strakes can vary in thickness depending on the size of the vessel and what it is being used for. Steel quality has improved over the years and with additional corrosion resistance and malleability, the thickness can be slightly less than in past decades. Access to light and durable steel has resulted in lighter and faster ships that can carry more payloads. When applying the long strakes (or steel plate) over the hull frames, workers refer to drawings that will give them specific dimensions and specify curvature for each strake or plate.

The required dimensions are transferred to the steel plates on large flat work areas called platens. Once cut, the steel sections are formed using rolls, large presses, or sometimes even huge gas torches that heat the strakes until they become the desired shape.

These strakes are trimmed to fit exactly onto the frames and then lifted into place. Starting at the bottom and working up, the strakes will be welded to each other until they form the watertight hull of the ship. Seams at the ends of the plates are staggered to provide structural strength. Many vessels will also have specialized strakes welded over the existing hull plate to provide protection when alongside jetties. These types of strakes appear as raised sections on the outside of the hull.