Caulkers

A caulker is a craftsman who applies caulk to seal joints and prevent water intrusion. The term is most closely associated with wooden shipbuilding and maintenance, where caulking was essential to make the hull watertight. Caulkers worked with a combination of material knowledge, manual skill, and physical endurance to complete demanding, cramped tasks below and along the ship’s interior.

In traditional wooden ships, caulking involved driving oakum—tarred fiber such as hemp or jute—into the seams between planks. Caulking irons were used to loosen and open seams, a caulker’s mallet to drive the oakum, and a hammer or other tools to pack the material tightly. After the oakum was packed, pitch or tar was sometimes applied to further seal the seam. The work was done after planking was fastened and could be performed during construction or in port and at sea during maintenance.

Tools and materials commonly associated with the trade include caulking irons, a caulker’s mallet, oakum, and protective pitch or tar. Precision was required to avoid overpacking, which could distort planks, or underpacking, which could leak.

In modern usage, caulking has broadened to sealing gaps with caulking compounds such as silicone, polyurethane, or acrylic sealants in buildings and manufactured products. The historic shipboard role of caulkers has diminished, though skilled restorers and traditional shipyards may employ caulking techniques for period-accurate work.