steelhull

A steel hull is the hull of a ship or boat constructed primarily from steel plates and sections. Steel hulls are the predominant choice for modern seagoing vessels because they offer high strength, durability, and design flexibility across a wide range of sizes.

Historically, steel progressively replaced iron and wood from the late 19th into the 20th century. Early ships used riveted steel plates, but welding became standard in the 20th century, enabling stronger joints and faster construction. The development of double-hull designs, especially for oil tankers, reduced the risk of catastrophic spills by providing an inner protective barrier.

Construction involves forming a hull from frames, floors, keel, and plating, then joining plates by welding or, in some cases, formerly riveting. Modern hulls may be designed as monohulls or multi-hulls and incorporate ballast tanks, watertight compartments, and structural reinforcements to meet prescribed loads and stability criteria. Steel grades vary from mild steel for lighter structures to high-strength, low-alloy steels for critical members, with protective coatings and cathodic protection to control corrosion.

Advantages include a favorable strength-to-weight ratio, good damage tolerance, relative ease of fabrication, and mature repair infrastructure. Challenges include corrosion and fatigue, brittle fracture in cold conditions, and the need for regular maintenance, coatings, and inspections to prevent hull breaches.

Applications cover most cargo ships, container vessels, bulk carriers, tankers, and many naval vessels; submarines typically use steel hulls for the pressure boundary, though some designs employ other materials for certain sections. Hull design is a central topic in naval architecture and shipbuilding.