The National Iron & Steel Heritage Museum
The Materials: Pros & Cons
WOOD — A historically popular material for shipbuilding because it was buoyant, widely available, and easily worked.  However, wood deteriorates easily.  The common types of wood used in shipbuilding include teak, cedar, oak, and pine.

BRONZE — A man-made alloy (mixture) of copper and tin, and sometimes other metallic elements. Bronze is less brittle than iron and is easily shaped.  Throughout history, it was used in shipbuilding because of its toughness and resistance to salt water corrosion.  Bronze can still be found in propellers and submerged bearings. 

STEEL — A precise alloy (mixture) of iron, carbon, and other natural metals.  It is stronger than iron and wood, which protects vessels from damage but is also heavier (about 30% heavier than aluminum).  Steel rusts unless protected from water, which often requires a finish, or a coating of another material like zinc.

Vessels are designed with several steel grades and shapes: a complex steel structure that meets requirements for cost, strength, flexibility, weldability, reparability, etc.

The steel shapes in ships include plates, strips, bars, rods, tubular products, and more. The steel grades in ships include HSLA (high-strength, low alloy), thermos mechanical control process steels, anti-corrosion steels (oil tankers), clad plate steels (chemical tankers), stainless steels, and more.

ALUMINUM — A natural metallic element that becomes a silvery-white metal when refined. Aluminum is used in sheets for hulls or for isolated structural members.  It is the lightest material for building large boats and easy to cut, but is difficult to weld and is very expensive.  Corrosion is also a concern with aluminum. 

FIBERGLASS — Glass-reinforced plastic.  It is easily molded but must be reinforced with another material in order to provide stiffness.  Fiberglass hulls are largely free of corrosion.

Photograph: Reliance under construction—Herreshoff Marine Museum