West Sea Company The U.S. NAVY MARK V DIVING DEEP INTO AUTHENTICATION By Rod Cardoza All photographs courtesy West Sea Company unless otherwise noted ©2000 West Sea Company. All rights reserved. Reproducing any part of this article without the expressed written consent of the author is forbidden by law. Violators will be prosecuted.



     In recent years a tremendous upwelling of interest in deep sea diving has surfaced. Mel Fisher’s discovery of an undersea fortune in the wreck of the ATOCHA and the epic movies “TITANIC” and “MEN OF HONOR” have moved diving and its allure to the forefront of public awareness. As an adjunct to the public’s enchantment with shipwrecks and diving, a fascination with the equipment used in the early days of underwater exploration has developed. Hard hat diving equipment is THE hot ticket amongst nautical antique collectors at present. And at the top of the list for every diving collector is the classic U.S. Navy Mark V diving helmet.

     A basic tenet in today’s economy, “supply and demand,” ensures that when money can be made, production will eventually match demand — even if that production is “Re”production. Therefore it is an unfortunate fact that a significant number of unknowledgeable and anxious would-be collectors have been fooled into placing what they think is a genuine diving helmet in their family room or den. For nearly 40 years helmets have been reproduced in Taiwan. To the trained eye, a Taiwan reproduction helmet is fairly easy to spot. Yet, the relative quality of the early reproductions and the fact that some have now “aged” for over 30 years makes them an easy sell to the unwary.

Circa 1980 reproduction Mark V made in Taiwan.
Side view of reproduction Mark V helmet.


1. Nearly 30 years of “aging” make this reproduction look believably authentic to the untrained eye.

2. Phone box is out of position.

3. Well-made reproduction sheet brass “Morse Diving Equipment Co., Boston, Mass.” maker’s tag with all nameplate data.

4. No sacrificial zinc.


1. Faceplate wing nut does not seat with a tapered fit as in authentic Mark V’s, but is squared off on the seating end.

2. The spacing of the exhaust holes in the banana valve is irregular and the holes are smaller than those of an original.

3. Absence of dumbell lock which should correspond to the slot in the lower neck ring.

More recently, a new breed of sophisticated reproduction Mark V has been coming out of Korea and England. These reproductions are being manufactured as out and out fakes, with the intent of fooling the novice and the undiscerning buyer. They are priced accordingly, being a bargain compared to the real thing, yet costlier than might be expected for a reproduction.

Korean Mark V
Recently produced Korean “super reproduction” Mark

At a Glance

     Even on sophisticated reproductions the various fittings are not as finely machined or professionally finished as those on an original. The air and phone goosenecks, spitcock, and exhaust valve may have “flashing” or unfinished edges from the casting process. The gooseneck fittings (elbows) on most reproductions are not open to the inside of the helmet and the angle at which these goosenecks extend from a reproduction helmet tend to be different from those on a genuine example.

     Most reproduction helmets tend to be more squatty than the originals after which they were copied. The arch described by a reproduction breastplate is usually flatter and would protrude markedly from the chest and back if worn on the shoulders; that is assuming it could be worn at all! On most Taiwan reproductions three metal bolts protrude through the interior of the neck ring to hold the breastplate to the bonnet. This makes donning the helmet extremely uncomfortable if not impossible.

     Another feature of a genuine helmet is the “tinning” or grayish metal coating on the interior (and often the exterior) of the helmet. To date, no reproductions en masse, have been produced incorporating this detail. The English reproductions attempt to mask this feature by using a chemically-produced dark oxidized finish on the copper.

Reproduction English Mark V
Recently produced English “super reproduction” Mark V.

Photo courtesy P. K. Chandran, Historical Diving Society, U.S.A.

Another Version of a Reproduction English Mark V that recently “Surfaced”

   Recently reproduced Korean Mark V’s utilize a combination slotted/philips head screw uniquely produced in the Orient. Original Mark V’s contained only slotted screw heads. Prior to 1945, components of a Mark V were attached and sealed by “soft solder” joints. After World War II silver solder was used. The silver alloy is harder than the earlier tin/lead variety. Factory soldering done by manufacturers was even and “clean” with smooth concave “fillets” between the joints of major components. Reproductions are lacking in the quality of solder work as compared to originals.

     A genuine Mark V helmet with brales and wing nuts weighs approximately 55 pounds. Most reproduction Mark V helmets weigh half as much, due to the parsimony of manufacturers in minimizing materials and keeping reproduction costs low.

The Bonnet

     Most genuine diving helmets were subjected to rigorous use. So a few dents and scratches are to be expected on authentic examples. Also, helmets that were used in underwater cutting or welding often bear small pits on the faceplate and breastplate as a result of contact with the ejection of hot slag from such work. Distress is easily faked however.

     On helmets used in Naval service, the U.S. Navy’s inspector’s mark — the initials “U S” with a small anchor between — was usually stamped on the exterior of the phone box or on the faceplate. The mark was about 1/4 inch across. The absence of such a mark is no indicator that the helmet is a reproduction however, as a large number of Mark V’s were used in commercial applications, and not all were inspected.

U.S.N. Inspector’s Proof Mark
Super close-up of the U.S. Navy’s inspector’s mark. To date this mark has not been replicated on even the highest quality reproductions, and as such is a very good indication of authenticity.

     The phone box is a raised cylindrical brass cap with a smaller rearward protrusion fitted on the (diver’s) left front of the helmet between the top and left ports. It housed the electrical transceiver by which the diver communicated with the tender on the surface. Two small threaded machine screws were soldered into the phone box to hold the speaker, while several half inch flexible brass tabs were situated within the bonnet to hold the phone cable leading from the phone gooseneck to the box.

     One of the earmarks of the Mark V diving helmet is its unique hinged faceplate. The glass, measuring 0.3″ thick, was beveled and normally sealed with a pinkish orange hard putty known as litharge and white lead, as were the 3 other fixed glass ports known as “lights.” The wing nut on the pivoting stud extending from the bonnet was tapered opposite the butterfly to fit precisely into a receiving “cup” of the two pronged fork on the faceplate. To prevent the wing nut from unscrewing completely a small circular “keeper” was swaged onto the end of the stud. Again, reproductions do not replicate these details and quite often reproduction faceplates do not seat smoothly or tightly.

Wing Nut
Faceplate wing nut assembly.
Wing Nut Keeper
Blown-up view of the end of the faceplate stud showing the swaged keeper.

     On the (diver’s) left front of the helmet is the spitcock. It was originally designed for taking water samples, but divers commonly used it to expectorate, hence the name “spitcock.” A reproduction spitcock frequently has a loose or “sloppy” action. A spitcock on an authentic helmet has a smooth, watertight action. It opens to the inside of the bonnet with a 1/4 inch orifice surrounded by a 1 1/2 inch diameter flange. The shape of an authentic spitcock handle is made in a right angle gracefully curving in an elongated bulb to a tapered, rounded end. Many reporductions omit such a detail using an uncurved right angle handle of “roundstock” with a flat end. We have also noted that the angle or position of reproduction spitcock handles are often incorrect. On an authentic helmet, the spitcock handle faces rearward with the axis of rotation being horizontal.

Close-up of the pet cock valve known as the spitcock. Note the small threaded locking screw which allows the lever to only travel within the notched seat. Reproduction helmets do not have this detail.
Spit Port
Internal side of the spit cock.

     A rectangular brass plate situated on the exterior of the helmet above the spitcock, fitting neatly between the front and (diver’s) left side ports, was used to attach a piece of “sacrificial zinc.” The “zinc” was designed as an anti-electrolysis agent to help retard corrosion. On some authentic helmets this bar was drilled and tapped for screws to attach the anode. Most reproductions are absent such detail.

Close-up of the small plate on the front of the helmet to which a piece of zinc was attached.

     A genuine Mark V bonnet is attached to the breastplate with a 1/8th circle “bayonet” twist interrupted thread. Due to the complexity of machining such threads, most reproductions do not duplicate this feature. Instead, Taiwan reproductions use a rather crude system of three ferrous hex bolts protruding out of the interior neck ring to secure the two components.

     To ensure that the bonnet was affixed to the breastplate in the centered, working position, a safety pin or “dumb-bell lock” was employed. The lock is similar in appearance to a miniature weight lifter’s dumbbell. The dumbbell is pivoted off of the back of the bonnet and fits into a slot on the neck ring of the breastplate. To prevent the dumbbell from coming out of the slot a formed piece of brass, the dumbbell lock retainer clip, was attached to the neck ring. It pivoted on one end and was secured by means of a cotter pin attached with a small chain on the other.

Dumb-Bell Lock
The complete dumbbell lock assembly. The dumbbell pivots outward and the retainer clip pivots open like a gate.

     The exterior air and phone goosenecks (elbows) are open to the inside on original Mark V’s. The “opening” of the air supply gooseneck may not be readily apparent however, as it leads to the air supply channels or vents, soldered to the inside of the helmet. Some helmets had a third gooseneck, for supplying electricity to heated suits. The air supply gooseneck was fitted with an in-line, screw-on “non-return valve” which prevented air from accidentally escaping from the helmet, in the event of a cut hose or other air supply failure. Many original Mark V’s will be found with this non-return valve still in position on the gooseneck.

Non-Return Valve
Non-return valve in position on the gooseneck of an authentic Mark V.
Non-Return Valve Close-up
Close-up of a non-return valve with the maker’s name stamped into the side.

      One feature of a genuine helmet virtually never found in the early reproductions is the interior air passages. As mentioned, these vents channeled incoming air from the air supply gooseneck across the inside of the bonnet and over the viewing ports. This action kept the inside ports from fogging up, much like the concept of the car window defroster. It should be noted that vents are in evidence in the latest Korean and English reproductions.

Bonnet Interior

The inside of a Mark V bonnet.


1. The flared vents which spill air onto the three ports or “lights” within the helmet preventing them from fogging with condensation.

2. The small round gray clips and the two threaded studs to hold the communicator and its cable.

3.  Tinning on all surfaces.

      On helmets manufactured prior to 1929, an eight point exhaust handle was used. In response to divers’ complaints that they were unable to ascertain the position of the exhaust valve handle, the Navy implemented an unnumbered modification, which replaced the eight-pointed handle with a four-pronged variety featuring an enlarged bulb on one of the prongs for reference. Most of these “new” style handles were manufacture by the Batteryless Telegraph Equipment Co. whose logo, “BTE,” was cast into the center. Frequently, the helmet manufacturer’s name was lightly impressed on the circumference of the exhaust valve cover bracket, just behind the valve handle. Note that the lack of the BTE logo is NOT an indicator the helmet is a reproduction.

Early Exhaust Valve
Close-up of the early version Mark V exhaust valve as originally configured. Note the uniform 8 prong valve handle with no markings.
Later Exhaust Valve
Close-up of the later version of the Mark V exhaust valve handle. Note bulbous center prong and the “BTE” logo.

     On the inside of the helmet, opposite the exhaust valve, is the “chin button,” a circular brass piece on a stem looking much like a car engine intake valve. The diver depressed this spring-loaded device, using his cheek or chin, to quickly dump air or reduce buoyancy without the necessity of adjusting the exhaust or chest valves. At the same time the Navy implemented the change to the exhaust valve handle, a “beefed up” double spring exhaust was introduced, which provided the diver with a more positively seating chin button.

Chin Button
Close up interior view showing the chin button. The chin button is on the interior of the helmet and opposite the exhaust valve handle on the exterior.

     To guide exhaust air to the rear of the helmet so that bubbles would not obscure the diver’s vision, a rounded exterior brass channel with perforations at the rearward end, extended from the exhaust valve to the rear of the helmet. Owing to its shape, it was called the “banana valve”. The banana valve is present on both reproduction and authentic Mark V’s. However the gauge of metal used in the originals is heavier, and the perforations form a more uniform pattern.

Banana Valve
Side view of the banana valve. Note the even spacing of the holes in the exhaust diffuser.

     Most Mark V’s were originally finished with a thin coat of tin to help retard corrosion of their relatively thin sheet copper shells. Later Mark V’s were often tinned in their entirety, even including some of the cast brass components. But for the most part this is rare. This “tinning” gives the original Mark V a dull silver/gray appearance. Depending on the degree of use and/or restoration, tinning may or may not be extant. Evidence of tinning on a helmet is a very positive point in its authentication. Tinning should not be confused with the soft solder used in fabricating authentic and reproduction helmets. A sloppy solder job can give the appearance of tinning.

Original Mark V Helmet with Tinning
Authentic Mark V showing original tinning of exterior surfaces. Note that the ports, faceplate, phone box, and other fittings are not tinned.

     A precious few “deep water,” “mixed gas,” or “Heli-Ox” helmets made their way into U.S. Navy service by the Second World War. These so-called “Gas Hats” allowed the diver to overcome nitrogen narcosis by breathing a special helium/oxygen mixture, and thus dive many times deeper than a conventionally-rigged air hat. The deep water helmet consisted of a basic Mark V with the spitcock feature and two goosenecks removed and adapted to receive and mix the oxygen and helium in the proper proportions, by means of a large brass cannister at the rear. Overall, it made for a massive and very ungainly apparatus. Nevertheless any collector who is lucky enough to acquire one of these bulky monsters is truly fortunate indeed. No reproductions of the deep water version of the Mark V are known.

Deep Water Mark V, also known as a “Heli-Ox” or “Gas Hat”.

The Nameplate

     The nameplate is one of the most important and telling features used to identify a diving helmet. Only four companies produced authentic Mark V diving helmets. Today only one of the original four, DESCO, is still in production. Morse was bought out and its facilities moved to a new location. The new “Morse” company continues to reproduce Mark V’s on order and knives. The original companies were Morse Diving Equipment Company, Boston, Mass.; A Schrader’s Son, Brooklyn, N.Y.; Miller-Dunn Diving Co., Miami, Fla.; and Diving Equipment and Salvage Co. (later Diving Equipment Supply Co.) Milwaukee, Wis. Each manufacturer had unique nameplates. Mark V nameplates manufactured by the Morse Diving Equipment Co., Boston were elliptical, either of thin cast or sheet brass construction, showed the stamped day, month, and year of manufacture, and were affixed by both rivets and soldering. Those by DESCO were (and are still being produced on special order) elliptical sheet brass, showing the month and year only, and also affixed by rivets. Most, but not all tags on the Miller Dunn Co., Miami, Florida helmets were made of cast lead. But a few were cast brass. The tags produced by A. Schrader’s Sons were thick cast brass, rectangular with rounded ends and attached by soldering only. Schrader tags bore the month and year of manufacture. The most frequently duplicated nameplates are those of Schrader and Morse. Commonly, reproduction Mark V helmets will bear the sheet brass nameplate of the Morse company, while the heavy cast tags of the Schrader company adorn belt buckles.

Reproduction Mark V Tag
Genuine Mark V Tag
A beautifully executed, early reproduction tag for the Morse company. The details are accurate. But notice the serial number is conspicuous in its absence. Later reproduction tags of this form are missing all of the stamped data.
Authentic nameplate from the Schrader company. Note the relatively rough cast resolution of the letters. Compare this to the reproduction Morse tag at left.

     Most Mark V nametags encountered bear the “MOD 1” inscription. MOD 1 appeared on Mark V tags of the first production run by Schrader which current research indicates to be in June 1917. It is possible that MOD 1 refers to positioning of the inlet and communications elbows (goosenecks). Although Morse appears to have produced Mark V’s earlier (#2289 date Feb 24, 1917. L. Leaney, Historical Diver Magazine, Summer 1993) they did not indicate “MOD 1” on their tags until WWII production somewhere between helmet #4497 date 9-14-42 and #5000, date 2-44. (L. Leaney, 1994, unpublished research). This is assumed to be an oversight at Morse, a fact that is confirmed by Ken Downey of Morse Diving Co., who notes Morse “ran out” of tags marked MOD 1 for a time during World War II. Various other modifications and improvements were introduced during the Mark V’s production life, 1916 through circa 1984, when the Navy replaced it with the Mark 12.

The Breastplate

    On a real Mark V the first stud on the right (diver’s) side of the breastplate is longer than the others. This so-called “bastard stud” was the attachment point for the air control chest valve or “whip.” The whip was fastened to the front of the breastplate by means of an adjustable brass bracket. As rigged for diving, the air supply hose from the surface was fed into the whip, through the bracket, and then on to the gooseneck at the rear of the helmet. In this way the entire assembly was secured by means of the bracket.


Whip Assembly
Close-up of the attachment of the chest valve and whip. As shown, the air supply hose from the surface would enter from the left (the diver’s right) and extend across the chest (hence the name) to the support bracket. In this rig a second point of support can be seen on the left side of the breastplate (diver’s right) further securing the whip.

     Prior to the advent of the Mark V, all helmets had been provided with breastplate studs from which to hang weights necessary to overcome the buoyancy of the suit. The Mark V was designed exclusively for use with a weight belt buckled around the waist and supported by shoulder straps. Studs on the front of the breastplate were replaced by eyelets used to lash the air hose and telephone connections securely. These eyelets protrude through the breastplate and are visible on the inside as convex solder discs about the size of a 50 cent piece. The shoulder contour of a genuine Mark V breastplate is generally in a more pronounced arch than that of a reproduction. Schrader Mark V’s in particular have a very deep fitting breastplate


Contemporarily produced reproduction Mark V diving helmet made in Taiwan in 1998
Front View
Side view


1. No sacrificial zinc in between the front and left (diver’s) ports.

2. No “BTE” markings on the exhaust valve handle and no enlarged singular “reference” prong.

3. No stampings on nameplate; date and number fields are blank.


1. Shallow arch described by the curve of the breastplate.

2. Phone box is in wrong position — on top of helmet vs. in between top and left ports.

3. Goosenecks pointing inwardly rather than primarily downward, as with an authentic Mark V.

4. Dumbbell does not fit within the channel designed for it on the neck ring.

5. The spitcock valve handle is not curved to a bulbous point and is slightly canted.




     The diver’s suit, or “dress,” was a one piece heavy rubberized canvas jumper with a number of rubber openings in the collar. In use, these openings were slipped over the studs on the breastplate. Four contoured brass straps called “brales” were then fitted over the studs and cinched down with wing nuts, sandwiching the suit between the brales and the breastplate. Genuine brales are solid, while most reproductions have a channel on the underside to save on the amount of brass used in their manufacture. At the joining points of the brales — front, back, and two sides, were thin rectangular brass “tabs” used to keep the joints from pinching the the suit. Also used at these joints was a unique type of wing nut with a round, broad flange on the seating side. Many brales were stamped “FRONT” and “BACK” or “L” and “R.” Some bore serial numbers matching that of the helmet. Most reproducers do not replicate the tabs nor the marked brales. 

Serial Numbers

     Serial numbers are marked on all authentic nameplates. In addition, matching serial numbers were sometimes stamped on either side of the centerline bench mark on the front of the breastplate neck ring and correspondingly on the bonnet ring. Morse usually serialized their bonnets in this way. According to Ken Downey of Morse Diving Co., sometimes Morse placed the “job number” on their tags, while the helmet’s actual “serial number” appeared on components. Schrader typically stamped the matching nameplate number inside the bonnet neck ring. Others we have encountered have the serial number stamped on the exterior of the phone box. Some manufacturers also chose to serialize the brales, either on the tops or on the undersides. The Mark V was a working helmet, frequently found in the company of numerous others in a diving locker. So as a matter of course bonnets and breastplates could be interchanged. It is not uncommon to find Mark V’s with numerically mismatched components. But as a matter of originality however, collectors generally prefer helmets with matching numbers.


     The Mark V hard hat diving helmet is no longer being used by the U.S. Navy, having been outdated by more modern helmets incorporating state-of-the-art lightweight materials and the latest advances in diving physiology. In all, these strides afford the modern diver more mobility, comfort, duration, and ease of communication. However, the venerable and well-proven Mark V is still in use in various parts of the world today.

Because of the desirability of the genuine Mark V diving helmet as a collectible now, prices have steadily increased in the last several years. With the increased scarcity of authentic helmets have come higher prices and a flood of reproductions and fakes on the open market.

If you are considering acquiring an authentic Mark V, or any type of genuine underwater diving helmet, the easiest and safest course of action is to contact a reputable dealer.


Try your knowledge at picking out which of the 3 diving helmets shown is the real Mark V. Give at least 4 reasons. Answers are contained at the end of our catalog page 10.

Can YOU Spot the REAL Mark V?
Photo ourtesy P.K. Chandran, Historical Diving Society, U.S.A.


1. Lesley Leanie, “Historical Diver” Magazine, The Official Publication of the Historical Diving Society, U.S.A., Santa Barbara, Calif., Summer 1993, Summer 1995.

2. McKee, Alexander, “King Henry VIII’s Mary Rose”, Stein &Day, New York, 1973.

3. Nautical Brass magazine, Jan/Feb 1981, Sept/Oct 1982, Nov/Dec 1983, July/Aug 1984.

4. The U. S. Navy Diving Manual, Superintendent of Documents, U. S. Government Printing Office, Washington, DC, 20402.

5. Andrew J. Morse & Son, Inc., “Catalog of Diving Apparatus,” 1925. Edition 5M, Andrew J. Morse & Son, Inc., Boston, Mass.

6. “Diving Notes,” U.S. Naval School, Deep Sea Divers, U.S. Naval Gun Factory, Washington, D.C., PRNC-D5D5-6, Revised October 1952.

7. Leon Lyons, “Helmets of The Deep,” 1988, Leon G. Lyons, Hollywood, Florida.

8. Arthur Bachrach, Barbara Desiderati and Mary Matzen,” A Pictorial History of Diving,” 1988, Best Publishing Co., San Pedro, California.


© 1998-2013 West Sea Company. All rights reserved. Reproducing any part of this article without the expressed written consent of the author is forbidden by law. Violators will be prosecuted.