All equipment necessary to ensure propulsion and steerability of the ship, safety of passengers and crew, cargo, ship and machinery. Essential equipment is subdivided into the primary and the secondary ones.
- Primary essential equipment – The equipment required to be operative at all times to maintain the propulsion and steering of the ship.
- Secondary essential equipment – Equipment required for safety of the ship, passengers and crew. It can briefly be taken out of service without propulsion and steering of the ship being unacceptably impaired.