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Alvin Observer Pre-Dive Briefing

In preparation for a dive in Alvin, observers participate in a dive briefing process designed to provide basic familiarity with the submersible's capabilities, systems, normal and emergency procedures. The briefing process begins with a group meeting in the ship's library, followed by an external 'walk-around' of the vehicle. The briefing concludes with a tour of the sub's personnel sphere and internal systems. Topics covered during the various portions of the dive briefing are as follows:

Observer Requirements

In addition to the above, all prospective observers are evaluated for physical condition including:

  • Ability to exit the personnel sphere in an emergency without aid of the sphere ladder
  • Any medical conditions which might preclude or disqualify them from participating in a dive
  • Overall mental attitude toward enclosed, sealed spaces (observed during the in-hull portion of the dive briefing)
  • All personnel entering the vehicle must be capable of passing through the hatch with its sealing surface protection ring in place, which has a 19” maximum opening.

Library - Introduction and General Overview

  • Daily dive routine and schedule
  • Basic life support overview
  • Alvin O2 system overview
  • Alvin CO2 scrubber overview
  • EBA overview
  • EBA mask sizing and test fit
  • In-hull situational awareness
  • Shipboard life and general safety considerations

Alvin - External Systems Walk-around

  • Science basket and workspace
  • Manipulators
  • External lighting & lasers
  • External cameras & pan/tilt units
  • Viewport locations
  • Service release description & locations
  • Frangibolt release description & locations
  • Pre-dive personal gear preparation & clothing guidelines
  • In-hull environment
  • Toxic & flammable material limitations
  • Post-dive gear retrieval
  • Dive lunch and beverage description
  • Personal hygiene & restrictions on makeup, lip balm, heavy perfumes, etc.
  • Waste elimination bottles & post-dive disposal
  • Medical considerations
  • Hatch ingress

Alvin - Internal Sphere Tour and Systems Overview

  • General sphere and equipment locations
  • Tool kit, first aid kit, trash and seasickness receptacles, cabin lighting, life preservers, flashlights
  • Communications overview
  • VHF radio operations (for surface communication)
  • Underwater telephone (UQC/EDO) operations (primary subsurface communication)
  • Orcatron Subphone operations (backup subsurface communication)
  • Sound-powered phone operations (communication with support swimmers)
  • Alvin computer system & user interface
  • Navigation and science computer and data interface
  • Video system and camera operation
  • Video monitor and recorder overview
  • Video overlay overview
  • Audio recording and digital recorders
  • Operations Manual location & observer emergency procedure section
  • Life support system locations and overview
  • Electronic and manual atmosphere monitors
  • O2 system operation
  • CO2 scrubber operation & absorbent canisters (Sofnolime and lithium hydroxide)
  • Sleeping bag use
  • EBA operations & mask locations
  • Emergency surfacing overview
  • Service bus & service release operations
  • Emergency power panel  & emergency release (Frangibolt) overview and operation
  • Atmosphere casualty and in-hull fire response overview
  • Emergency Off breaker
  • Battery operated automatic cabin light
  • Fire extinguisher location & operation
  • Service Selector rotary switch


The temperature in the personnel sphere can range from 95°F on the surface to 50°F on the ocean bottom.  Layered clothing is recommended to allow adaptation to changes in internal temperature. Although a fire in Alvin is extremely unlikely, wool or cotton are preferred to most synthetics for flammability resistance and personal protection.  Nylon fabrics and materials are not allowed in the submersible.