Deep Sea Diving

Diving Equipment Product Specifications

DESCO Diving Helmets Hose Connections

All Classic Style DESCO Diving Helmets are fitted to accept 1/2" Navy air hose with a 1 1/16" -17 Submarine Thread. Adapters are available to other fitting configurations. The air inlet elbow and non-return valves are male threads to the female hose end.

The DESCO Air Hat and Browne Masks accept 5/16" or 3/8" air hose with a 9/16-18 Oxygen Thread. This fitting is a standard CGA welding fitting.

Diving Helmet and Mask Air Requirements

DESCO Helmets

DESCO uses the air flow requirements as set forth in the U.S. Navy Diving Manuals for the Mark V Helmet as a benchmark. Any DESCO Classic Style Helmet or the Air Hat has an absolute minimum necessary airflow rate of 6 cfm at rest to properly ventilate the helmet. As activity increases the airflow rate must be increased to offset buildup of Carbon Dioxide in the helmet. For the Air Hat a minimum working flow rate of 10cfm is recommended. Overbottom pressure is 100psi constant.

Diving Masks

The Browne Mask was developed for the US Navy during World War Two. They have the most extensive and complete working knowledge of the performance of these masks. DESCO defers to them on the air requirements for the Browne Masks.

Excerpted from the 1985 USN Diving Manual:

Flow requirements 6.4.3.1 The Jack Browne mask requires constant gas flow to prevent excessive accumulation of metabolically produced carbon dioxide. When planning a diving operation ensure the primary air supply system is capable of providing an average sustained flow of 4.5acfm for each diver including the standby diver. In addition, for short durations of heavy work, the air supply system must be capable of providing each diver in the water with a flow of 6acfm.

Pressure requirements 6.4.3.2 When using the Jack Browne mask, an overbottom pressure of 50psi must be maintained.

DESCO Air Hat

Threading Specifications;Air Hat

  • Air Inlet (double elbow) 1/4" NPT
  • Non-Return Valve (inlet, umbilical) 9/16"-18 Oxygen (CGA 022 B size)
  • Non-Return Valve (outlet, helmet) 1/4" NPT
  • Window Screw #10-32 NF
  • Video Block 3/8"- 16 NC
  • Double Exhaust Valve Retaining Screw #6-32 NC
  • Clamp Bolt Threading 1/4"-20 NC
  • Lock Bolt Threading 1/4"-20 NC
  • Clamp & Lock Nut 1/4"-20 NC, Self Locking
  • Communications Pigtail Port 1/8" NPT

Minimum air flow rate for DESCO Air Hat = 6cfm  @ 100psi over bottom pressure.
Microphone/Speaker is held in place with 3M® VHB Double Sided Foam tape.
Inside Air Elbow and pigtail bulkhead fitting is epoxied in place with 10 minute two part epoxy.
Neck ring gasket is glued in place with sanding disk adhesive.

Approximate shipping weight is 34lbs.

The Air Hat can be used with the provided neck dam or with drysuits fitted with a DESCO type yoke.

The complete DESCO Air Hat Manual is available for download on the Downloads Page.

DESCO Air Hat Welding Shield

Lens dimensions 4 ½" x 5 ¼"
Screws #10-32 x 7/8" Stainless Steel

U.S. Navy Diving Helmets

The DESCO Mark V and Helium Helmets are made to U.S. Navy specifications as prescribed in the Bureau of Ships drawings.

Helmets listed below all use the Navy Mark V style dress collar.

U.S. Navy Mark V Diving Helmet

Threading Specifications;

  • Air Inlet Elbow threading is 1 1/16" - 17 (Submarine Thread).
  • Communications elbow threading is 1.715 - 11.
  • Front Door Toggle Bolt threading is 1/2" - 13 NC.
  • Window Guard Screws are  #8 - 32 NC.
  • Breastplate Stud threading is 1/2" - 12 NS.
  • Neck Ring Threads (interrupted) 9 13/64" - 6 NS
  • Head opening in Neck Ring  8 9/16"

Approximate shipping weight is 68lbs

U.S. Navy Helium Helmet

Threading Specifications;

  • The common parts between the Mark V Helmet and the Helium Helmet are identical (see Mark V specs).
  • High Pressure Nozzle threading : 3/4"-16
  • Discharge Nozzle threading: 3/4"-16
  • Canister Elbow threading: 2 3/4"-8

Approximate shipping weight is 93lbs with canister.

Communications is via a standard Navy Mark V type plug.

DESCO Commercial Diving Helmets

The DESCO Commercial diving helmets all use a common breastplate and bonnet platform. This breastplate style was used by multiple manufacturers. Some DESCO Commercial Helmets were produced using the Mark V bonnet shell in lieu of the standard "bubble" shell.

Models vary by window configuration, exhaust type, and optional features. Refer to the helmet pages for detailed information on each model's features.

Helmets listed below all use the Commercial style dress collar.

Three and Four Light Commercial Helmets

Threading Specifications;

  • Air Inlet Elbow threading is 1 1/16" - 17 (Submarine Thread).
  • Front faceplate threading is 5 13/16" - 20 NF
  • Communications elbow threading for Navy communications elbow is 1.715 - 11 .
  • Communications elbow threading for Commercial style elbow is 1 1/4"-12.
  • Window Guard Screws are  #8 - 32 NC.
  • Breastplate Stud threading is 1/2" - 12 NS.
  • Neck Ring Threads (interrupted) 9 13/64" - 6 NS
  • Head opening in Neck Ring  8 9/16"

Approximate shipping weight for Three Light Helmet 54 lbs.
Approximate shipping weight for Four Light Helmet 58 lbs.

DESCO Nuclear Diving Helmet

Threading Specifications;

  • Air Inlet Elbow threading is 1 1/16" - 17 (Submarine Thread).
  • Front faceplate threading is 5 13/16" - 20 NF
  • Window Guard Screws are  #8 - 32 NC.
  • Breastplate Stud threading is 1/2" - 12 NS.
  • Neck Ring Threads (interrupted) 9 13/64" - 6 NS
  • Head opening in Neck Ring  8 9/16"

Approximate shipping weight N/A at this time.

DESCO Commercial Fisheries Diving Helmet

Threading Specifications;

  • Air Inlet Elbow threading is 1 1/16" - 17 (Submarine Thread).
  • Communications elbow threading is 1.715 - 11.
  • Window Guard Screws are  #8 - 32 NC.
  • Breastplate Stud threading is 1/2" - 12 NS.
  • Neck Ring Threads (interrupted) 9 13/64" - 6 NS
  • Head opening in Neck Ring  8 9/16"

Approximate shipping weight is 58lbs.

  

DESCO Lightweight Helmets

DESCO Lightweight Helmets are constructed on a common breastplate and bonnet shell platform often referred to as a "Sponge" type. the breastplate type was made by multiple manufacturers.

Models vary by window configuration, exhaust type, and optional features. Refer to the helmet pages for detailed information on each model's features.

Sponge Divers Helmet

Threading Specifications;

  • Air Inlet Elbow threading is 1 1/16" - 17 (Submarine Thread).
  • Front faceplate threading is 5 13/16" - 20
  • Side window frame threading is 4 5/8" - 20
  • Top window frame threading is 4 5/16' - 20
  • Exhaust valve cover threading is 1 3/4" - 16
  • Exhaust valve cover lock screw threading is #8 - 32 NC
  • Neck Ring Threads (interrupted) is 8 15/16" - 6
  • Head opening in Neck Ring is 8 3/8"
  • Breastplate stud & wing nut threading is 7/16" - 14

Shipping weight is approximately 39 lbs.

Abalone Divers Helmet

Threading Specifications;

  • Air Inlet Elbow threading is 1 1/16" - 17 (Submarine Thread).
  • Front faceplate threading is 5 13/16" - 20
  • Window Guard Screws are  #8 - 32 NC.
  • Neck Ring Threads (interrupted) is 8 15/16" - 6
  • Head opening in Neck Ring is 8 3/8"
  • Breastplate stud & wing nut threading is 7/16" - 14

Shipping weight approximately 39 lbs.

Agar Divers Helmet

Threading Specifications;

  • Air Inlet Elbow threading is 1 1/16" - 17 (Submarine Thread).
  • Front faceplate threading is 5 13/16" - 20
  • Window Guard Screws are  #8 - 32 NC.
  • Neck Ring Threads (interrupted) is 8 15/16" - 6
  • Head opening in Neck Ring is 8 3/8"
  • Breastplate stud & wing nut threading is 7/16" - 14

Shipping weight approximately 39 lbs.

Browne Commercial Diving Helmet

Threading Specifications;

  • Air inlet port in block (for Non-return valve) 1/2" NPT
  • Communications cable port in block (for bulkhead fitting) 9/16" - 20
  • Front window threading is 5 13/16" - 14
  • Side and top window threading is 5 1/8" - 14
  • Neck Ring Threads (interrupted) is 8 15/16" - 6
  • Head opening in Neck Ring is 8 3/8"
  • Breastplate stud & wing nut threading is 7/16" - 14

Shipping weight approximately 45 lbs.

DESCO Lightweight Fisheries Diving Helmet

Threading Specifications;

  • Air Inlet Elbow threading is 1 1/16" - 17 (Submarine Thread).
  • Window Guard Screws are  #8 - 32 NC.
  • Neck Ring Threads (interrupted) is 8 15/16" - 6
  • Head opening in Neck Ring is 8 3/8"
  • Breastplate stud & wing nut threading is 7/16" - 14

Approximate shipping weight N/A at this time.

  

DESCO Special Helmets

DESCO Stillson Concept Diving Helmet

The DESCO Stillson Concept Helmet uses a Commercial pattern breastplate and bonnet shell.

Threading Specifications;

  • Air Inlet Elbow threading is 1 1/16" - 17 (Submarine Thread).
  • Communications elbow threading is 1.715 - 11.
  • Window Guard Screws are  #8 - 32 NC.
  • Breastplate Stud threading is 1/2" - 12 NS.
  • Neck Ring Threads (interrupted) 9 13/64" - 6 NS
  • Head opening in Neck Ring  8 9/16"

Approximate shipping weight is 59lbs.

DESCO Browne Utility Diving Helmet

The DESCO Browne Utility Diving Helmet uses a "stove pipe" yoke to attach to a drysuit. A DESCO yoke can be used.

Threading Specifications;

  • Air Inlet Elbow threading is 1 1/16" - 17 (Submarine Thread).
  • Communications elbow threading is 1.715 - 11.
  • Window Guard Screws are  1/4"-20 NC.
  • Neck Ring Threads (interrupted) 9 13/64" - 6 NS
  • Head opening in Neck Ring  8 9/16"

Approximate shipping weight is 21lbs.

DESCO Browne Masks

Threading Specifications;

  • Non-Return Valve (inlet, umbilical) 9/16"-18 Oxygen (CGA 022 B size)
  • Air Inlet Elbow 1/4" NPT
  • Air Inlet Elbow retaining screws 10-32 NF
  • Exhaust Body to Mask frame 7/8"-18 NS
  • Exhaust Cover to Body 6-32 NC
  • Air Control Valve to Air Inlet Adapter 3/4"-16 NF
  • Air Control Valve Inlet and Outlet 1/4" NPT
  • Breather Bag Outlet (Navy Three Way Valve) 7/8"-18 NS
  • Inlet Nipple and Retaining Nuts (DVM) 3/4"-16 NF
  • Freeflow Valve Handle (DVM) 1/4"-20 NC
  • DVM Air Inlet Adapter 1/4" NPT inlet, 3/4"-16 NF outlet.

Diving Dress Collar Dimensions

Navy, Cat No 26005
Front to back OD = 25.625”  ID = 17.875”
Across shoulders OD = 18.125”  ID = 10.375”

Commercial, Cat No 26056
Front to back OD = 22.250”   ID = 14.750”
Across shoulders OD = 19.625”   ID = 12.125”

Lightweight, Cat No 26055
Front to back OD = 23” ID = 16”
Across shoulders OD = 17.750” ID = 10.750

Contact our deep sea diving specialists today for dive equipment product details or any additional diving inquiries.