Bathyscaphe: diving apparatus used for deep-sea observation.
Access to the bridge: opening for getting in and out of a bathyscaph.
Propeller: two- or three-bladed apparatus.
Towing fair lead: hook used for towing.
Metal hull: metal cladding.
Observation light: apparatus that projects intense beams of light used for observation.
Observation porthole: small, round, thick watertight window used for observation.
Cabin (sphere): cockpit.
Navigation porthole: small, round, thick watertight window used for observation.
Rudder: apparatus used to turn a boat.