furring

Furring consists of thin wooden strips or battens fastened to the inner surface of a ship's hull planking, running parallel to the frames and keel. The strips are typically 25 to 50 millimeters thick and serve to create a level internal surface where the hull may have warped, settled, or been built with natural curvature. They bridge gaps between the outer planking and the cargo hold interior, effectively creating a secondary skin that improves the usable volume of the hold and provides a cleaner surface for cargo stowage.

The practice differs between new construction and repair. In new hulls, furring is often applied selectively to problem areas where the hull curvature is pronounced or where planking has developed irregularities during assembly. In older vessels undergoing reconditioning, furring may be installed more comprehensively to address decades of hull settlement and movement. The strips are secured with wooden dowels or iron fastenings driven through to the outer planking, holding them firmly in place without creating through-holes that might compromise the hull's watertightness.

Moisture and decay concerns

The primary risk with furring is moisture entrapment between the battens and the hull planking. When ventilation is inadequate, wood rot develops rapidly in this enclosed space, particularly in warm, humid climates and on vessels in tropical service. Shipwrights must allow air circulation between the furring strips or apply protective treatments such as tar or copper coating to the inner hull surface before furring is installed. Regular inspection of furring in older vessels is essential, as decay can compromise the structural integrity of the hull planking itself if left unchecked.

Furring appears in the accounts of wooden ship construction from at least the 17th century, and the term likely derives from the Old French fourure, meaning lining or stuffing. The word has persisted in maritime vocabulary even as modern steel vessels use different methods to manage hold surfaces, such as welded internal frames or composite linings. In contemporary wooden and composite vessel restoration, furring remains standard practice for achieving cargo-ready interiors.