A sailboat companionway is the main entrance/exit hatchway leading between the cockpit and the cabin below, typically featuring a sliding roof hatch, vertical washboards (hatch boards) or doors, and a set of steep steps. Designed for secure, watertight access, this transitional space often includes a raised sill—or "coaming"—to prevent water from entering the cabin.

Key Companionway Parts:
Sliding Hatch/Cover: The horizontal sliding or hinged panel covering the top of the opening.

Washboards/Hatch Boards: Removable, stacked wooden or polycarbonate planks that slide into vertical grooves to seal the cabin.

Companionway Doors: Hinged or sliding alternative to washboards, often manufactured from fiberglass, wood, or acrylic.

Steps/Ladder: A small set of stairs leading from the deck into the interior.

Hatch Frame/Coaming: The structure framing the opening that provides structural integrity and keeps water out.

Design Variations:
Angle: Companionways are often sloped (especially on production boats) to allow for easier molding and more comfortable seating in the cockpit.

Watertight Doors: Some vessels utilize special watertight doors, while many others use washboards that can be secured with a lock.

Screening: Simple screened panels can be used for ventilation and to prevent insects from entering the cabin.

These parts are designed for both security and ease of entry while ensuring the crew can lock up in rough weather, often using accessories like a "dodger" or bimini for further weather protection.