The Boats of the
BRAGADIN Class

by Cristiano D'Adamo

Air Systems
The compressed air system was one of the most important systems on the submarine. It was used to blow the ballast tanks, fire torpedoes, and to start the main engines. Without a functional air system the submarine became inoperable. Docking facilities were usually provided with the necessary high-pressure air supply so that the submarine would not have to produce its own. Air tanks tended to accumulate condensed moisture (water), thus they were regularly drained for maintenance.

On the Bragadin the primary air compressor was installed in the compartment forward of the control room. It was build by San Giorgio and capable of pressurizing air up to 200 kg.cm2 (2845 psi) and having a reserve of up to 6,000 liters. The compressors were powered by electric motors. There were also two super compressors, also built by San Giorgio, capable of boosting air pressure from about 70 to 200 kg.cm2 (995 to 2845 psi). This system received air from the two compressors built into the diesel engines and air was stored into tanks with a total capacity of 6,202 liters (219 ft3).

The main and crash tanks

These compressors could only be used when the submarine had at least the cunning tower out of the water so that the hatch could be open to supply external air. There were also two low-pressure blowers type Reavel-Cerpelli (less than 1.7 atmospheres) capable of 30 m3. The blowers shared the same electric motors as the asset pumps, each capable of moving about 60 tons of water per hour. In case of emergency, the pumps used to launch torpedoes, each capable of about 30 tons per hours, could also be used to move ballast water. The boats were also equipped with emergency pumps driven by low-pressure air or manpower. These hand-operated pumps were capable of about 120 liters per hour (4.238 ft3/h)

Air Filtering System
The Bragadin were equipped with an air regeneration system for the removal of CO2 (Carbon Monoxide). There were also oxygen tanks loaded which were used to oxygenate the depleted air while submerged. The submarine was equipped with external hookups so that, in case of malfunction, a support ship could blow the ballast tank and also provide breathable air.

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