1841. Bikkers Rotterdam
An architect writes about diving apparatus manufactured by ‘BIKKERS’
Around the mid-1830s, the Dutch Bikkers firm of Rotterdam was manufacturing fire-fighting equipment. However, following the import of the English made ‘Deane’ diving apparatus into Holland (see the ‘1836 DEANE HELMET’ chapter) Bikkers was inspired to manufacture the first Dutch diving helmet.
According to the book ‘Verbeterde Duikertoestellen’ (Improved Divers Apparatus) published by A. Bikkers & Zoon in 1886, the first diving apparatus manufactured in Holland took place when a new bridge in Rotterdam was to be built to connect ‘de Boompjes’ with ‘de Bierhaven’ and ‘de Scheepmakershaven’. The original bridge dated from 1613, but in 1839 a new bridge was built and was known as the ‘Groote Draaibrug’ bridge. This bridge was designed and built by Captain-Engineer WILLEM NICOLAAS ROSE, town-architect for Rotterdam. He preferred to build his bridge without closing the waterway to ships and instead chose to use divers for the underwater construction. In the book, W.Bikkers describes how he designed a 2-cylinder air pump, a suit, hoses and a copper helmet. He dived his equipment in March 1841 to demonstrate its reliability to the bridge builders. After W.BIKKERS had spent 15 minutes at the bottom, W.N.ROSE, ‘satisfied about the long stay under water’ dressed up in the diving apparatus to convince himself of the steady air supply from BIKKER’s pump and the ‘waterproofness’ of the dress. This convinced W.N.Rose to purchase the equipment for the town of Rotterdam and he wrote an account of his experience of the dive which was published in Amsterdam in 1843.
While constructing the new bridge over the ‘Scheepmakershaven’ in Rotterdam of old, known by the name of ‘Groote Draaibrug’; the town council decided, instead of using expensive dams to have the works of the foundations carried out using divers. This work consisted of widening and strengthening the existing foundations. The widening would be needed on both sides of the piers using concrete that required underwater sheet piling. This work was performed by divers, and underwater construction details are as follows.
Probably during the construction of the first bridge pine beams had been put side by side, right across the ‘Scheepmakershaven’. A section of these beams is shown on plate 9 with a, b Fig.1. On these the piers were placed of which the old foundation still exists shown with c, d, e, f. To be able to widen these to g and h yokes i, g, h and k had to be placed. Adjusting these happened with the guiders and laying beams l m n and o which were connected by shores. The lower ends of the yokes had been given iron points which got hit in the pine beams, and were given for extra safety iron hinges on the outside and on top iron hooks. The installing and fastening of this ironwork was the first the divers had to do. Next had to be placed floors i c and d k between the legs of the yoke and the old pier on which walls i g and h k had to be set up and nailed. All this work would not cause much inconvenience on the surface and could be carried out by the most simple carpenter, but now this had to be performed of 4,50 dutch ell beneath the water level, in a strange element in which every move is difficult each mistake is dangerous and where above all the water is rarely clear enough that you can see 0,60 dutch ell away, and so very much has to be carried out on grope, making this not only a difficult, but also a heavy and, with the least thoughtlessness dangerous work.
The construction above shows the fundaments of a bridge built in Rotterdam in 1839, the diving equipments used for the under water part of the job were supplied by Bikkers of Rotterdam. Engraving David L.Dekker collection.
First to take care of was dressing the diver properly and have all tools in good condition: the clothes waterproof, the pumps well functioning, the air hose letting the air pass properly through, etc. The diver starts with taking off his upper-clothes and puts on a woolen vest, drawers and socks, then a 0,30 dutch ell wide belt made of wool covered cane is fastened around the body, a kind of lined vest fastened around the neck, the wrists bandaged with linen, strew with lycopodium ( = moss, DD ) every revolution and then fastened with thin ropes; after this the waterproof cloth, made in one piece is put on to him, fastened around his neck with a cloth and around the wrists again bandaged the same way, owing to this the whole man is water free except his head and his hands; finally they put him on another pair of woolen socks and a woolen nightcap. Equipped in this manner he goes to the raft and starts putting on a pair of shoes, heavy 11.00 dutch pounds, hereupon the helmet is put on his shoulders and is provided with 4 rings a a Fig 2 at the neck, where ropes must be put through to hang the weights on, and has three windows provided with thick glass, which each are protected by thick copper wire, placed as crossbars; whilst the middle window can be opened. The frame must be well greased and the closing is done by a bolt b. At the back of the helmet to a thread the hose is connected which has to be waterproof and who’s other end is connected to an air pump. The helmet does not rest on the head; you can move in it freely, which is needed indeed because the helmet weighs 10.00 dutch pounds; on the front and on the back of the helmet are hanging pieces of linen, o,65 dutch ell long, in the front piece is a big bag, wherein the workman stores his tools, nails, chalk and little planed planks. Thereafter a life-rope is tied around his waist. The lower end of it consists of an iron chain, long 2.60 dutch ell, and it is the chain which goes around the body. Now 2 lead weights of 19.00 dutch pounds each are done on the body Fig 2 at g shows the place and how the ropes are put through the rings a. Finally a rope, tied around the left arm is, rolled up, given in the divers left hand.
The equipment supplied by Bikkers for the works at the bridge in Rotterdam which was largely inspired by the ‘Deane’ diving apparatus imported in Holland only three years earlier.
Engraving, David L.Dekker collection.
Being all ready, they start pumping, meanwhile the diver climbs off the ladder and ties the end of the rope given in his hand to one of the ladders lower rungs, and next he lets it slip accordingly as he withdraws; as well the body-rope is paid out by him, who holds it on the raft; this should be done tactfully, so never more as needed, but enough for the diver to be moving freely, and, at all time followable by the directing person, not only in which direction he goes but also which bends and turns he makes.
This post demands much attention and cannot be trusted to everyone because the life of the diver depends partly on his watchfulness and policy; for he notices that the diver goes in the wrong direction, he keeps the rope taut; comes any obstruction or inconvenience he pulls the diver back sometimes, when he judges it necessary, all to the surface; that is why at the work mentioned above at all time a boss or overseer was present.
Is now everything well-installed, then only the divers hands get wet, the well foreseen bandages around the wrists prevent the water from entering the sleeves; the woolen clothing the strong cooling of the man during the time he is in the water; the belt the pinching of the weights against his lumbars; the vest the pressing of the helmet on the shoulders and the chest-bone; the weights on the helmet prevent the uprising of it, while they, together with the heavy shoes, give the man the necessary weight to remain master of his moves ( the weights, with the helmet and shoes together weigh 59 dutch pounds ) This load is really inconvenient above the water, but in it it is not more then enough; also the diver is in this respect completely comfortable in a way that many stayed down for more then one hour, and having sometimes worked for two hours before longing for a rest.
During the diver is in the water they have to continue pumping without a stop, the delay of a few minutes would cost him his life. The hose carries the air out of the pump into the helmet from which underneath she gets pressed out like big bubbles, which appear at the water-level; hereby you do not only know where the diver is, but one also quickly learns judging, wether he receives the necessary quantity of air; the supplied quantity of it does not only serve him for breathing, but also to press away the used air and prevent the uprising of water in the helmet.
Arrived at his destination the diver starts his labour: fits measures, saws, drills, cuts or nails all where it is required, these last two works are very difficult and wearing; with every strike, his arm must cleave the water fast. He must therefor be given very heavy tools; the hammers weigh 6.00 dutch pounds. Do you take in consideration that he can not bend because the belt prevents him, and with to far bending of the head the water would run into the helmet, which dues him to keep it up at all time and do all work standing up, sitting or kneeling, then you can imagine the aggravation of this labour.
By a few in advanced arranged signals, the diver gives notice of his wants; does he want something else or is he not understood then he writes it on one of the little planks, which, let go of, emerge; they fasten the desired item to the body rope and notice him by two short pulls whereafter he ropes it in; unfastens the item and notifies them two equal pulls to bring the rope back to its former position.
Has he achieved his labour, or does he want to cease it, so he stores all in the pocket, catches the rope fastened to his left arm and following it he comes back at the foot of the ladder, and when he does not want to continue his labour he unfastens it and climbs up.
Mostly he longs for a rest of some time; and then they let him keep the dress and thats underneath, but give shoes helmet weights and further belongings to another diver who continues the labour.
When the weather is not to warm the tired diver is brought in a room where they made a fire, which has to be done to avoid a quick cooling, because he generally comes up very warm and sweating. On a raw rainy day it was sometimes peculiar to see how they who had been standing on the raft for a long time got wet and cold while the diver who had been underwater for the same time came up very warm and dry.
The sensation you experience when you go underwater, has, when it happens for the first time, something strange, particularly for them who are acquainted with swimming and diving; involuntarily you hold your breath, and find soon with some surprise, that this goes as easy as above the surface. The compressed air does probably make you breathe a larger quantity then usual; soon you experience a pleasant inner warmth which diffuses quickly to all limbs, and provides a really pleasant sensation.
Less pleasant is a painful pressure on the eardrum, and inconvenient is the deafening sound of the many air bubbles, specially when they supply a to large quantity of air. This could be in such a way, that you become to light, and all weights are not sufficient, to remain master over your movements. You can hardly imagine the almost ridiculousness of someones situation, who is respect of the element wherein he finds himself, almost weighs nothing. You stay with each posture in an entire slope position, float over the mud without sinking in it, you believe to be rising and can do very little to get out of this situation, many do come to the surface then and ask to may receive less air because otherwise they can’t accomplish anything.
Does the opposite take place and isn’t the exhaled air quickly pushed away, then the diver comes in an unpleasant situation, particularly when during hard labour heavy respirations are made. They start feeling headaches, then dizzy, and do not turn back or neglect to be pulled up, then their life comes in danger; owing to this they almost lost one of the best divers, fortunately was the directing person, who held the body rope, very watchful and because you can tell after some experience, the slightest motions apart, they seemed so strange to him that he decided to bring up the workman immediately, which was done just in time. These cases are however rare and would never happen, if not a to far carried ambition made the workers commit imprudences. The fear to be derided by their comrades, the desire to belong to the best divers and more other reasons, are causes for that they neglect warnings and count it below their honor to return for minor inconveniences. In this uncertainty it is at all time better giving to much air then to little.
One observation you very soon do underwater is that there is very little to see and this is really a disappointment. Many would think that because you are in a more or less transparent corpus the visibility should extent proportional in it, that is true in theory but practice learns that many attendant circumstances change this in such a way, that it becomes of very little significance.
The first you perceive with regret, is the quick decrease of daylight, further the air bubbles streaming out bring the water around the head in such a waving motion, that all looks as if you look through a thick and bent grass. Then the mud set in motion starts troubling the water and finally the glasses of the helmet become gradually dim, which is a matter of course when you ate notice of the big difference of the temperature inside and outside of it; there is nothing you can do about this dimming because as you can not get your hands under the helmet, you are neither able to wipe the dimmed glass.
Notwithstanding all these drawbacks and difficulties all the work has been done in five months, initially they had only one diving apparatus, gradually this number came to three at where it stayed. The most that was done was keeping three divers at work, and to be able to do this they had to take turns again and again. This taking of turns was necessary because the job was making tired, which was caused by the fact that underwater the simplest labour becomes difficult and hard, for example during the placing of the floors in the sheet pilings they initially thought that small parts of the floor would be fasten able; that was a mistake, after a tiring wrestling the carpenters had to let them slip away so they immediately emerged. Then bigger pieces were chosen, weighed and made heavier in the middle with weights, tied on the plank with a thin rope in a cross, and further constructed in a way that when these ropes were cut the weight could be pulled up, and now it was possible to fasten them.
With the planks of the sides they had less trouble, these were brought down between two gaff formed pieces of wood and kept until they were nailed to the legs of the yoke. All this work has been performed with most good faith and diligence, the repeated inspections have confirmed the above expectation. Among the more then 25 workers who worked as divers there was only one who immediately, driven by fear, came up again, only a few who just dared a couple of journeys, most maintained until the last and some were down for more then 150 times, worked with diligence often with enthusiasm, in such a way that sometimes imprudences were committed. The confidence of the workers was mainly based on the conviction that everything was treated with calmness and deliberation, each detail directed with tact, and all precautions were taken by the town-foreman, the gentlemen Braacx, Tollenaar and Leeuwenburgh, who were particular in charge with this, in order to avoid accidents as much as they were able, and bring the work to a desired end. The good result must be attributed mainly to that diligence and policy. Further we feel obliged to mention, that the waterproof clothes and indiarubber hoses are manufactured by mister van Geuns of Haarlem, answered their purpose, while the weights, helmet and air pump manufactured by the gentlemen Bikkers and son, town fire engine manufacturers, did not only answer their purpose but they also showed that the leather hoses they manufactured could replace the indiarubber ones. Their continual presence, interest and care were often useful, and ascribe mainly to the fact that the air pumps never failed.
In conclusion we must herewith make some remarks, which possibly can be useful for them who want to work under water this way.
Recommendations made about the diving apparatus are as follows:
A. The belt is very inconvenient.
B. The weights are positioned too high which unbalances the diver, therefore the weight belt should be lower down and the weights divided for better weight distribution being carried by the diver.
C. The helmet is too large and too heavy, and the ‘fogging’ problem on the windows needs to be solved.
The underwater work would have been more convenient if the divers were able to see more clearly and if the surface workers had been able to talk to the divers during a dive. However it may not be possible to solve these problems as ‘Mr. Geuns of Haarlem and Mr. Dingler of Hellevoetsluis’ have already tried and failed through experimentation. Although the project worked well and was successful, if more diving projects were undertaken, then experience and improvements in diving apparatus would bring about more cost effective underwater work and an increase in underwater safety for divers.
The Bikkers Company was established in 1783 at the Goudsche Wagenstraat 64 in Rotterdam. According to a town guide from that era, Bikkers was working as a coppersmith. While reading the story of the diving experience by Architect W.N.ROSE it is clear that he dived the so called ‘open dress’ diving apparatus of the same style as the apparatus supplied by DEANE. An engraving showing the diver under water also confirms this. While accounting his diving experience W.N.ROSE explains that ‘initially they had only one set of diving apparatus, gradually this number increased to three sets, where it stayed’. At the end of his account W.N.Rose suggests ways to improve the diving apparatus. This implies that the apparatus used may have been more or less ‘experimental’.
1874 - 1886. The Bikkers ‘closed’ diving dress with 8-bolt helmet
Improvements to the Bikkers helmet were soon made following the suggestions of W.N.Rose in 1841, but the date when these improvements were introduced is not accurately known. In 1993 I purchased a set of 13 engravings in Rotterdam, two of which show Bikkers diving apparatus. One engraving shows both the Bikkers 8-bolt diving helmet and the French diving apparatus manufactured by the ‘Societe des Specialites Mecaniques Reunis’. This was a company established in 1874 by Auguste Denayrouze, founder of the company Rouquayrol – Deanyrouze. However, in 1885 successor Charles Petit bought the company. Because of this specific name (‘Societe des Specialites Mecaniques Reunis’) the engravings can be dated between 1874 and 1895. The oldest Bikkers sales catalogue which illustrates the ‘closed’ diving dress is dated 1886, which suggests the year that Bikkers made the first ‘closed’ diving apparatus is somewhere between 1841 and 1886. (I hope to be able to narrow the date span but I have yet to find any supporting documents). The Bikkers helmet shown in that catalogue and the engraving both illustrate is the oldest version of a helmet which had a breastplate that used brails and 8 bolts.
The helmet shown above is currently the oldest Bikkers helmet known to exist. The helmet left the factory exactly like the helmet shown in the engravings, but at some stage its owner decided to have the breastplate modified to the standard of an English Siebe Gorman helmet. This was done because the original Bikkers design had a rather unique 8-bolt system to attach the suit; the Siebe Gorman 12-bolt system later became the worldwide standard. Also the exhaust-valve was replaced by an English one and a spit-cock was added. Bikkers later manufactured his more recent helmets with the English 12-bolt breastplate. Helmet: private collection. Photographs, David L.Dekker
A diver dressed up in a Bikkers equipment. Photo Rob Krul collection.
1886. The Bikkers 3-bolt helmet (Systeme Denayrouze)
The Bikker sales catalogue of 1886 not only shows an 8-bolt helmet, but it also shows a Denayrouze style, 3-bolt helmet. The Bikkers Company supplied 40 complete set of 3-bolt diving apparatus to the Dutch navy. This apparatus was more or less a direct copy of the French Denayrouze apparatus and was dived with a ‘regulator’ back-pack. Bikkers also offered the Denayrouze-Charles Petit ‘lock’ helmet model that is advertised in their 1889 sales catalogue (see the Denayrouze chapter for further details). In a 1904 document there are several photographs of this 3-bolt helmet being used by the Dutch navy. This article suggests that the Dutch navy initially used diving apparatus supplied by the French Denayrouze Company (see chapter: ‘1860. Rouquayrol Denayrouze’). It is quite likely that the apparatus imported from France was used as a sample by Bikkers to manufacture his own 3-bolt diving dress. However, the 3-bolt helmet Bikkers produced is more heavily built than the original Denayrouze helmet.
A beautiful example of a surviving 3-bolt Bikkers helmet. Helmet, Leon Lyons Collection, St. Augustine, FL. USA. Photographs, David L.Dekker
The images below illustrate that the Bikkers 3 bolt-helmet was also used without the ‘regulator’ back-pack and that the Dutch navy also used the 3-cylinder Bikkers pump. The quality of these pictures is quite poor as they were used as illustrations with an article published in 1904 (I only have this article as an old Xerox copy).
1886. The Bikkers ‘regulator back-pack’ (Systeme Denayrouze)
The invention of the Rouquayrol-Denayrouze ‘regulator’ diving apparatus was not only received with enthusiasm in France and Germany, but also here in Holland where its modern design soon caught the attention of the diving fraternity. The Bikkers Company of Rotterdam saw a potential use for this new invention. In their sales catalogue of 1902, a well known article was reprinted which had been initially published in the magazine ‘Tijdschrift van het Koninklijk Instituut van Ingenieurs, Afdeling Ned.-Indie, Jaargang, 1899-1900’ (the ‘Magazine of the Royal Institute of Engineers’, Netherlands Indies Dept., 1899-1900). The article, ‘Working Under Water Without a Divers Suit’ explains the advantages for the use of the ‘regulator’ diving equipment for work in the various Dutch colonies. The article states that the regulator was manufactured in the factory of Bikkers & Son in Rotterdam, but as I have not come across a single example of the regulator, I have no further evidence of that. The Dutch could just as easily have imported the regulator direct from Denayrouze in France or from one of the German producers. (As the French patents for the regulator had expired the regulators were also manufactured by Ludwig von Bremen, Franz Clouth and Friedrich Flohr in Germany).
The Dutch view at that time thought that native divers in our colonies were not physically strong enough to work in the heavy diving apparatus with the heavy copper helmet. Local divers could only perform underwater work by holding their breath for a few minutes at a time. But with the new ‘regulator’ apparatus (called an ‘air-backpack’ in Dutch) the native divers could work without the need for a heavy suit and still work underwater for many hours...
The regulator Bikkers offered for sale first appears in their sales catalogue of 1886. In the text it states that the regulator was made of ‘hammered copper’. Rouquayrol-Denayrouze initially made their regulators from iron and there is one French regulator that exists which is made from brass. This brass regulator has the badge of ‘Charles Petit’ which dates it somewhere between 1885 and 1926. It can be viewed in the exhibition of the museum dedicated to the invention of the regulator in the French town Espalion and where Benoit Rouquayrol was born in 1826. The museum has a large collection of different types of diving apparatus and is well worth a visit:
Musee du Scaphandre 14 Rue Dr. Tremoliere 12500 Espalion, France Tel. 05 65 44 09 18 Fax. 05 65 44 78 95 Opening hours:
May, June and September: 2 PM till 6 PM July and August: 10 AM till 12 AM and 2 PM till 6.45 PM Special arrangements for groups
A photograph taken in 1910 showing a dutch navy diver with a Bikkers 3 bolt equipment. Photo: collection Hein Pater. The officer at the left is R. Waaijerink. He was a dutch navy diver himself as well, and the grandfather of Hein Pater’s wife.
This 3-bolt Bikkers helmet is in the exhibition of the HISTORY OF DIVING MUSEUM in Islamorada, Florida USA. The diving museum is the largest in the world so do try to visit it when you are in Florida. This helmet has a 3-bolt Bikkers breastplate complete with a bonnet from a French Denayrouze helmet and estimated to be somewhere between 1885 and 1930. Since the Dutch Royal Navy used both the Denayrouze and Bikkers helmets, this helmet may have been used as it is shown.
Photograph, David L.Dekker collection. Helmet, collection: (have a look at that website and do the virtual tour!)
Another surviving Bikkers 3-bolt helmet is in the possession of the Dutch navy at Den Helder (see photographs below). However, this helmet is actually a Bikkers breastplate married with a bonnet from a German ‘Draeger’ diving helmet (see chapter: ‘1899 DRAEGER HELMET’).
Circa 1900. A new style Bikkers 8-bolt helmet.
Back to the Bikkers 8-bolt helmet. I have no documentation indicating when a new version of the Bikkers 8-bolt helmet was introduced but it is clear that two versions of this helmet do exist. The older-style helmet was still in the Bikkers sales catalogue of 1902.
First style 8-bolt helmet
Second style 8-bolt helmet
The engraving on the left shows an early 8-bolt helmet design and the color photograph on the right shows the 8-bolt helmet in its final version. By comparison, the shape of the breastplate is not curved anymore but is instead flat; the exhaust-valve is no longer on the breastplate but on the helmet; the front-window design has been simplified and all window cross-guards are now heavily cast. The braille nuts are no longer hexagonal but of the Siebe Gorman type and the breastplate now has studs to hang the weights from. In addition, the more recent helmet has an acoustic telephone connection on top of the helmet and two brass eyes to attach the air-hose to. The diver’s air-hose is usually positioned under one of the divers arms and then tied somewhere to the front of the diver or alternatively to the helmet. This avoids excessive strain on the brass connector at the back of the helmet when an air-hose is pulled hard. The force of any hard pulls are taken directly by the divers arm and not directly by the connector which could break off under direct strain.
1902. The Bikkers sales catalogue offered 3 types of Diving Apparatus:
DIVERS APPARATUS No 1. This apparatus was designed for use in shallow water. It had a Denayrouze 2-cylinder air-pump of the second style ‘Pompe Hydraulique’ (see ‘Denayrouze’ chapter) which was used in combination with the regulator back-pack and the 3-bolt helmet. According to the 1902 sales catalogue, this apparatus was adopted by the Dutch Royal Navy who bought 40 complete sets.
This well conserved Bikkers helmet is part of the collection of Jaap Stenger in Belgium (
DIVERS APPARATUS No 2. This apparatus was designed for use in deeper water. According to the catalogue the apparatus is a ‘Dutch invention’ manufactured by the Bikkers Company since 1843. ‘No. 2 Apparatus’ used a 3-cylinder air-pump which supplied enough air to have two divers connected to it at the same time. The apparatus could be used with the 3-bolt helmet, the ‘lock’ helmet or the 8-bolt helmet.
DIVERS APPARATUS No 3. This apparatus was designed for use in the Dutch colonies. The air-pump was surprisingly, the same large 3-cylinder pump which was supplied with only a regulator back-pack and no helmet. Usually a 2-cylinder pump is sufficient for diving with a regulator back-pack because the diver needs much less air than diving with a ‘ventilated’ helmet. Bikkers still supplied twenty sets of the ‘Divers Apparatus No.3’ to the Department of Colonies and the Dutch Railroad Company. (For further information about the ‘regulator’ back-pack, see chapter: ‘1860 Denayrouze’).
The Bikkers 12-bolt diving helmet
The last design of the Bikkers helmet has a breastplate that is more or less identical to the Siebe Gorman 12-bolt diving helmet ( see: ‘1839 A. SIEBE’ chapter ) And a bonnet that is more or less identical to the Heinke ‘Pearler’ helmet (see: ‘1844 Heinke’ chapter ) The advantages of this Bikkers helmet were two-fold: firstly the helmet would fit the suits made by Siebe, Gorman which were in use by many diving companies nearly all around the world; secondly the helmet no longer had a hinged faceplate but instead a threaded screw-type faceplate. An interesting account comparing the advantages and disadvantages of specific faceplates was written by Barend Maaskant in his book ‘De Koperen Helm’ In it, he explained about the famous Dutch diver Martien Sperling was diving using a Bikkers helmet when a steel bucket hits the bolt securing the faceplate. The bolt broke off, the faceplate opened and within seconds his suit flooded with water. Sperling almost drowned that day. The last line of the account states ... ‘The possibilities of such serious accidents happening again came to an end. Instead of using a hinged window secured with a wing-nut, it was replaced with a faceplate which closed on the helmet by means of a thread’ ...
The application of a hinged front window on a diving helmet which was invented by Bikkers and later became widely used in the USA where all US Navy MK5 helmets and some commercial helmets were fitted which such windows. However, the American manufacturers built the hinge and locking-bolt mechanism horizontally onto the side of the helmet which helps reduced the risk of this type of accident happening.
The Bikkers 12-bolt diving helmet, original 12 bolt design ‘Model A’
The Bikkers helmet at the photographs above is of the original 12 bolt design. It has a ‘tulip’ style non return valve at the air connection and an exhaust valve with a long tunnel running almost to the top of the helmet. The bonnet was welded together from 2 parts. The brails are marked in dutch ‘VOOR’ ( front ) and ‘ACHTER’ ( back ) I call this helmet ‘Model A’ because there is a second version of the original 12 bolt Bikkers helmet existing. I do not know which one was the first design or the second design because the old style fittings on helmet ‘Model A’ suggest that it is the older version, but the the fact that the bonnet was electrical welded where the ‘Model B’ helmet has the old style ‘castelated’ hard soldered bonnet could indicate that the ‘Model B’ helmet was in fact the first one. Of this ‘Model A’ style Bikkers helmet several examples are known to exist. Photographs David L.Dekker
The Bikkers 12-bolt diving helmet, original 12 bolt design ‘Model B’
The Bikkers helmet at the photographs above is of a different 12 bolt design. It does not have the ‘tulip’ style non return valve at the air connection, and an exhaust valve without a tunnel. The bonnet was hard soldered together from 2 parts and also do the fittings on the helmet have a more ‘industrial’ look where the ‘Model A’ helmet has a more ‘artisanal’ look. The side windows are riveted to the bonnet. And on both sides under the face plate the helmet seems to have had Denayrouze style ‘rings’ to connect air-hose and communications cable to. For some reason these rings were removed and patched. Of this style of Bikkers helmets this is the one and only example known to exist. Photographs David L.Dekker
1983. Bikkers closes its business
Even though the Bikkers Company made some very interesting helmets, the quantities they produced were very limited. Bikkers remained a fire-fighting equipment manufacturer rather than a diving apparatus manufacturer and as a result, any Bikkers diving helmet is a rare helmet.
The stone relief plaque shown in the photograph above was presented to the Bikkers Company in 1883 to commemorate its 100 years anniversary. After the German bombing raids on Rotterdam this stone was about the only item that remained undamaged from the Bikkers Company. In 1983, exactly 200 years after the company was founded, Bikkers closed its business for the last time.
There is no surviving company archive or museum records for Bikkers, therefore I am eagerly searching for any additional information about diving apparatus manufactured by the company. If anyone has any old books, catalogues, photographs or apparatus, they are more than welcome to help complete the Bikkers story on this website.
Questions? Suggestions? Diving Equipment or Documentation for sale?
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