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Pisces IV Deep Diving Manned Submersible

Image of Pisces 1V


  • Length: 20'
  • Width: 10' 6"
  • Height: 11'
  • Weight: 13 tons
  • Payload: 250 lbs.
  • Crew: 1 Pilot 2 Observers
  • Life Support: 140 hours for 3 people
  • Max. Operating Depth: 6,500 ft. (~2000 m)
  • Power: 2 lead-acid battery systems:
    • 120 VDC at 330 Ah capacity
    • 12-24 VDC at 220 Ah cap.
  • Propulsion : 2 side mounted reversible thrusters tiltable through 100 degrees
  • Speed: 3 Kts.
  • Duration: 7-9 hours


  • Builder: International Hydrodynamics of Vancouver, British Columbia
  • Classed by American Bureau of Shipping
  • Materials: Personnel sphere, Trim spheres: HY 100 steel
  • Frame: Welded, oil-filled, pressure compensated 4130 tubular steel.
  • Viewports: 3 forward looking acrylic windows, 6" dia interior-14" dia exterior
  • Penetrators: (28) 316 SS inserts to pass electrical, hydraulic, air and oxygen supplies through the hull.


  • Oxygen and CO2 absorbent for daily use is sufficient for twice normal mission duration.
  • Independent emergency supplies available for 120 hours for 3 people.
  • Full face air masks available in case of cabin air contamination.
  • MSHA-NIOSH approved self-contained Oxygen-Generating Breathing Apparatus available for 3 crew.


Buoyancy Control

  • Soft ballast tanks displace a total of 1904 lbs. Using H.P. air.
  • Droppable descent/ascent weights.
  • Hard ballast tanks and hydraulically powered seawater pump give 450 lbs. of trim adjustment.

H.P. Air

  • Carried in 5 externally mounted cylinders with a total capacity of 600 scf at 3000 psi. Used for ballast system and emergency breathing apparatus.


  • Two 22 ft3 cylinders available for daily use. Independent emergency supply in 4 externally mounted cylinders has a capacity of 480 cu. ft. at 3000 psi.


  • Cabin Atmosphere is monitored by oxygen analyzers. Oxygen level is maintained by constant flow. CO2 is removed by a electrically powered scrubber unit and granular CO2 absorbent material.

Hydraulic System

  • Electric pump and solenoids provide 3 gallons per minute at 3000 psi to the following equipment:
    • HYCO manipulator
    • Basket basket up and down
    • Ascent/Descent weight drop cylinders
    • Thruster tilt
    • Movable drop weights
    • 2 camera pan and tilt system
    • Tiltable scanning sonar head
    • 2 spare functions for science equipment
    • A separate dedicated hydraulic system operates a Schilling Orion manipulator.

Controls and Instrumentation

  • The pilot has available all controls necessary for the operation of all submersible systems in both normal and emergency situations including thruster controls, buoyancy controls and indicators, battery condition instruments, depth and pressure gauges, magnetic compass, life support monitoring instruments and controls, and surface and underwater communications.


The submersible is equipped with the following items and can be configured as necessary to accommodate a variety of mission requirements.

  • Insite Pacific MINI-ZEUS HDTV camera
  • ROS low-light CCD color camera
  • B&W low-light wide-angle CCD
  • Digital video recorders
  • Two hydraulically operated manipulators
  • General purpose science basket
  • Applied Microsystems electronic CTD profiler
  • Tritech SeaKing digital HD sonar
  • Kongsberg-Simrad 1007 200 m altimeter
  • Benthos multi-frequency pinger receiver
  • TrackLink 5000HA USBL submersible tracking system
  • Sonatech long baseline acoustic tracking system
  • External lights: 3-250 W, 2-500 W tungsten 2-400 W HMI's available
  • 2 KVH digital magnetic compasses
  • Externally mounted temperature probes with internally mounted monitors
  • Suction sampler 8-bottle Rosette
  • Hydraulic cutters
  • Hydraulic rotary saw
  • Laser scaling system
  • Push core samplers
  • Sealable sediment scoops - 4 arrays of 9 samplers, capacity ~1kg ea
  • Water samplers - 2 arrays of 6 samplers, capacity ~700ml ea


  • Jettison equipment:
    • Main trim weight 500 lb
    • Port emergency drop weight 250 lb
    • Starboard emergency drop weight 250 lb
    • Thrusters can be jettisoned in the event of entanglement
  • Extended life support capacity for 3 to 5 days, mainly dependent on crew weight
  • Salt water leak detectors in bilge, battery boxes, electrical junction boxes, and controllers
  • Acoustic locating pinger receiver system
  • Emergency self contained re-breathers
  • Full face mask air breathing system for contaminated atmosphere
  • Emergency life support rations, water, and space blankets
  • One main and one backup 24 VDC emergency battery power banks to power:
    • CO2 scrubber
    • circulating fan
    • cabin lights
    • underwater telephone
    • VHF radio
    • tracking transponder
    • hydraulic solenoids
    • Soft ballast tanks have an accessible exterior port to allow a rescue vehicle to insert an external air source to add buoyancy.

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