Terhi boats are made by TerhiTec, a Finnish company founded in 1972 in Rymättylä, in the Turku archipelago of southwestern Finland. TerhiTec is part of the Otto Brandt Group, a Finnish family-owned industrial group, and the Terhi name also appeared earlier on outboard engines produced in Finland in the 1950s. Since then the factory has produced hundreds of thousands of boats, making Terhi one of Finland's best-known small-boat names.

Terhi is best known for simple, durable fiberglass hulls suited to Nordic conditions, ranging from classic rowboats and dinghies to small motorboats and fishing craft. Models such as the Terhi 385 have remained among the best-selling small rowing boats in Finland for years, and Terhi boats have been sold in large numbers across Finland and exported to many other countries. The boats are built for hard use and cold water, and many are kept for decades, passed between owners, and refitted with modern outboards.

Repair and maintenance manuals for Terhi boats cover the practical side of ownership: hull and deck maintenance and repair, fittings and hardware, steering and control cables, electrical systems and wiring diagrams for navigation and cabin equipment, and the servicing of the small outboard motors commonly fitted to these boats, with torque specifications and scheduled maintenance guidance. Simple jobs such as resealing fittings, servicing steering cables, and preparing the boat for winter storage are covered in the same practical detail as engine work.

Cottage owners, small-boat users, and independent boat repairers all benefit from accurate documentation, and owners of older Terhi models will find the material useful for keeping classic Finnish boats afloat.