Stocks are an external framework in a

shipyard A shipyard, also called a dockyard or boatyard, is a place where ships are built and repaired. These can be yachts, military vessels, cruise liners or other cargo or passenger ships. Dockyards are sometimes more associated with maintenance a ...

used to support construction of (usually) wooden ships. They are normally associated with a slipway to allow the ship to slide down into the water. In addition to supporting the ship itself, they are typically used to give access to the ship's bottom and sides.

References

Shipbuilding {{shipbuilding-stub