Alvin Observer Information

The following section is part of the Alvin Operations Manual and is intended to give the prospective observer an opportunity to review emergency procedures prior to embarkation. All procedures will be covered in detail during the predive briefing on board the vessel.


It is conceivable that during the course of a dive, the Pilot could become incapacitated due to injury or illness to an extent preventing operation of the submersible.  In such an event, the Observers or passengers must have sufficient information to act on their own in surfacing the vessel.  The purpose of this section is to provide step by step instructions for such a contingency.  Before the commencement of a dive, the Pilot must assure himself that each of the Observers understands these instructions and has adequate familiarity with the submersible controls to carry them out if necessary.

First, using the UQC, attempt to contact the surface for instructions.


Under most circumstances the submersible can be surfaced with normal power which is already available to the service releases and main ballast blow systems.  If, however, normal power is lost, or if the emergency jettisons are needed, special procedures are required to provide power.  Without normal power, the only interior light will be an automatically activated battery-powered cabin light and flashlights.

Emergency Power
If normal power is not available, locate the "GREEN Bus" power switch on the emergency battery panel (upper port side) and check that this switch is in the ON position.  Locate the service bus switches (top row on port panel) and turn off the CO2 scrubber to conserve power (Refer to 4.17.6, 1st NOTE).  Locate the "Service Selector" switch on the power panel (forward port side upper) and place the switch to "GREEN".  Locate the "Service Release" breaker below the service selector and ensure that it is on.  The entire service bus is now powered by the green battery and individual switches may be operated in the normal manner.  This includes service releases, main ballast system blow and vent, underwater telephone (UQC), navigation system that includes a tracking pinger and the carbon dioxide scrubber.  The green bus voltmeter (on the emergency battery panel) will indicate the voltage available to the bus and the service bus ammeter (above the service selector switch) will indicate the power being drawn.  Each battery can supply 1 amp for 3-5 hours.

Emergency Jettison Power

The red-bordered emergency release switches on the dump panel (top center) are powered by the emergency battery red bus.  These include battery tank releases and manipulator releases.  The only operation necessary to release one of these items is to lift the red cover on the emergency battery panel (you must cut the safety wire with tools in the drawer at the bottom of the science rack), place the switch to the ON position, and operate the appropriate switch on the dump panel.

Four emergency batteries are carried in the sphere; all are identical and are interchangeable by physically moving the batteries from one slot to another. The red and green batteries are connected to jettison and release circuits’ throughout the dive. The remaining batteries would be changed into those positions as required.


First, using the UQC, attempt to contact the surface for instructions.

If you do not contact the surface at the scheduled time, the Surface Controller will attempt to contact you.  If an additional 30 minutes passes without successful communications, the Surface Controller will assume you have left the bottom and are on your way to the surface.

If communication with the surface is not possible, proceed as follows.  Any of the following steps will surface the submersible in normal trim.  Perform only the minimum number of steps in the order listed below to get the submersible moving toward the surface:

  • Be sure the SERVICE RELEASE switch on the service bus (port side) is in the UP position.  Operate the service release(s) (forward top center panel) by holding the ENABLE switch in the down position and pushing up on each momentary switch for a minimum of one second.  This will release the remaining ascent/descent/ballast weights.  These weights are normally 250 pounds each and four are carried on most dives. Two are normally dropped during descent, just before reaching the bottom.
  • Blow ballast tanks at depths shallower than 1,000 meters ONLY.  Switches are located on the forward lower part of the port distribution panel.  Blow aft tank first.  If required, blow forward tanks by pushing the switches down.  Put no more air in the tanks than what is required to begin ascent.  At deep depths, little immediate effect will be noted, but the speed of ascent will increase with decreasing depth.  CAUTION:  Vent forward tanks with VENT switch (vent switch up and push button) for periods of from 1 to 2 seconds at about 300 meters depth and continue periodic venting until reaching the surface.  This is a precaution which will help prevent damaging the ballast tanks due to rapidly expanding air as the depth decreases.

NOTE: To activate any other function listed below, the emergency red battery must be brought online.

  • Release the sample basket.  Its weight will depend on loading and varies from dive to dive.  The procedure is the same as for the service weight releases except there is a red cover on the sample basket release switch which must be raised.

If the submersible has not started toward the surface after execution of the above steps, check that the red emergency bus is energized and proceed with the following emergency releases.  All switches are located on the upper edge of the top center panel and are bordered in red.

  • De-energize the "A" main battery (closest to ALVIN's center of gravity) by pushing down the 120 volt contactor switch located on the forward top center panel, under the emergency release switches.  Locate the emergency battery panel on the port side.  Break the safety wire and turn on the red battery.  Locate red "Emergency Release" switches, top center panel.  Operate either of the two battery "A" drop switches.  This will release the battery from the submersible.  If it fails to drop (no ascent) try the other "A" battery drop switch.  Remember to de-energize batteries before dropping by pushing down the appropriate 120A or 120B contactor switches.
  • If it becomes necessary, release the starboard manipulator by operating the "STBD Arm Cut" and "STBD Arm Drop" switches on the emergency dump panel, in that order.
  • Release the port manipulator by operating the "Port Arm Drop" switch.
  • Drop battery "B" in the same manner as above.  Prior to dropping this battery, shift the "Service Selector" switch to "green".  The normal interior lights will go out.

Life Support

Normal life support should be adequate until you arrive back on the surface.  The carbon dioxide scrubber is powered from the service bus and therefore capable of being powered by either the normal or emergency battery. 

NOTE:  If on emergency power, the scrubber is to be turned off and all personnel are to be using the EBAs.

CO2 can be detected by the installed monitoring device.  Oxygen flow has been preset and should require no adjustment.  Oxygen can also be constantly monitored with installed instruments.

In the remote event of an electrical fire, the atmosphere will quickly become contaminated.  Immediately open the "hold" breaker on the forward power panel near the right end of the "control bus".  All normal power and lights will be lost; the battery-powered cabin light should come on and flashlights are available. Don the emergency breathing apparatus as instructed in your pre-dive briefing, making certain that one of the emergency/reserve oxygen cylinder valves is opened and that the normal oxygen day cylinder valve is shut.  Ensure no flow is coming from the auxiliary flowmeter by visual indication and feel.  All other valves and controls are kept on.  Use fire extinguishers if necessary.  Emergency power can now be initiated on the service bus with the emergency battery.  The EBA units are adequate for at least six hours each.

On the Surface

After surfacing, attempt to communicate with the Surface Controller by radio.  Turn the radio switch on, select Channel 16 and identify yourself as "ALVIN".

Check sound powered phones to see if a Swimmer is aboard.  Do not open the hatch until told to do so either by a Swimmer on the sound powered phone, or by the Surface Controller by radio.

Predive 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 cabin and internal systems. Topics covered during the various portions of the dive briefing are as follows:

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 work area
  • 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 Cabin Tour and Systems Overview
  • General cabin 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 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 very 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.