planing

Planing generally refers to the process of making a surface smooth and flat by removing thin layers of material with a plane or similar tool. The term is used in woodworking, metalworking, and shipbuilding.

In woodworking, planing is used to produce flat, smooth faces and to reduce thickness. It is done with hand planes such as block, jack, smoothing, and jointer planes, or with power planers. Planing requires aligning with the grain, removing high spots, and jointing edges for flat panels. After planing, boards may be edge-glued and thicknessed, then sanded.

In naval architecture, planing describes a hull form that rises to glide on the water surface at sufficient speed, reducing wetted area and drag. Planing occurs when speed overcomes the weight-related resistance. It is common in small motorboats and high-speed craft. Planing hulls require adequate power and light weight; advantages include higher speeds and efficiency on smooth water, while drawbacks include reduced stability at low speeds and in rough seas, increased spray, and sensitivity to weight distribution.