The Nemrod H – 103 is an extremely rare rebreather that was used in Spain for military purposes. Only a few images of the system are known to me. The system designed by Nemrod José Ma Zapata was used by the Navy in the period from 1966 – 1972.
The Nemrod Museum managed by Rubén sent me the information below so that we could capture deeper knowledge about the H-103 in this web. I am very grateful to him for this and recommend everyone to visit his website via facebook. The original article published by him on the HDSES web I have been able to take over and translate into English. Happy reading!
El Museo Nemrod gestionado por Rubén me ha enviado la siguiente información para que podamos plasmar en esta web un conocimiento más profundo sobre el H-103. Le estoy muy agradecido por ello y recomiendo a todo el mundo que visite su web a través de facebook. El artículo original publicado por él en la web de HDSES he podido retomarlo y traducirlo al inglés. ¡Feliz lectura!
The “H-103” An autonomous closed-circuit device made in Spain by NEMROD (1965).
Ruben Castrillo – Nemrod Museum – 3 December 2024
Practically from the moment the Vilarrubís brothers’ company entered the diving equipment market, it began a successful relationship with the Spanish navy, to which it supplied a wide variety of equipment.
Many of these items were designed with the specific needs of Navy divers in mind, which made for excellent promotion of Nemrod items to the general public. What better attraction for any underwater enthusiast than knowing that the equipment they used every weekend was the same as that used at the Navy Diving Center?
However, for obvious reasons, there were items made exclusively for the Navy that were never sold to the general public.
One such item was the “H-103” independent closed-circuit oxygen equipment.
Combat units around the world have been using closed-circuit oxygen equipment since the 1940’s. For these units, closed-circuit had advantages over compressed air tanks, as they weighed less, offered more autonomy and did not produce bubbles visible from the surface. Their limitation was working depth, as from a depth of 10 metres, breathing pure oxygen is toxic, but for the vast majority of combat divers’ actions, this working depth was more than sufficient.
Thanks to the collaboration between Nemrod’s talented engineer José Mª Zapata and Lieutenant Rafael Fernández de Bobadilla, this simple but effective equipment was created that Navy combat divers were equipped with in the mid-1960s. It was named after the initial H (for hybrid) and the then-famous brandy 103, from the Bobadilla winery, which was owned by the lieutenant’s family.
After producing a fully functional prototype and carrying out the necessary tests in tanks under pressure and on the open sea, the company Vilarrubís y Sagué (Nemrod) patented this new equipment in 1965. A year later, during an event aboard the ship “Poseidon”, the Vilarrubís brothers personally delivered the first units of the “H-103” to the Navy.
The equipment consisted of a pair of steel cylinders filled with pure oxygen at a maximum pressure of 200 atm, a breathing bag, a regulator, a tank filled with soda lime that acted as an absorbent for the CO2 exhaled by the diver, and breathing hoses that ended in a mouthpiece with anti-return valves.
From the cylinders and after manually opening the valves, the oxygen reaches the regulator where the pressure is reduced. From the regulator and through the supply hose, the oxygen reaches the breathing bag and from there is inhaled by the diver through the tracheal inlet hose that ends in a mouthpiece. During the breathing process, some of the oxygen is consumed by the diver’s body. On exhalation, the unused oxygen passes along with carbon dioxide through the tracheal exhalation tube and then through the cartridge containing the soda lime. In the absorbent cartridge, the carbon dioxide is absorbed and the remaining oxygen is returned to the breathing bag. Here, it is mixed with pure oxygen from the cylinders and the whole process is restarted.
The maximum safe use level of this equipment was set at a depth of -10 m and with an actual autonomy of up to about 2 hours, as this was the point at which the absorbent cartridge became saturated and ineffective. Logically, autonomy varied depending on the depth at which it was used, the type of physical activity the diver had to perform and his experience.
Nemrod’s “H-103” was used in the navy from 1966 to 1972, when it was replaced by the French Fenzy “PO-68”.
The information on this and possible other Spanish oxygen systems is very hard to find. If you have additional information or a manual of the Nemrod H-103 I would greatly appreciate receiving this information or data!
La información sobre este y otros posibles sistemas de oxígeno españoles es muy difícil de encontrar. ¡Si usted tiene información adicional o un manual de la Nemrod H-103 agradecería enormemente recibir esta información o datos!
Therebreathersite was founded by Jan Willem Bech in 1999. After a diving career of many years, he decided to start technical diving in 1999. He immediately noticed that at that time there was almost no website that contained the history of closed breathing systems. The start for the website led to a huge collection that offered about 1,300 pages of information until 2019. In 2019, a fresh start was made with the website now freely available online for everyone. Therebreathersite is a source of information for divers, researchers, technicians and students. I hope you enjoy browsing the content!