Italian Submarines
Class ARGO and TRITONE

by Cristiano D'Adamo

	Main Page
Design and Construction	Propulsion	Air Systems
Crew Quarters	Blueprints	Radio, Navigation, etc.
Periscope	Controls	Weapons
Technical Specifications	Operational Activity	List of all Boats

Propulsion

Diesel Engines

The ARGO class was equipped with two two-stroke reversible diesel engines FIAT Q 274R. Each engine, capable of 420 rpm, produced 600 HP, but could be pushed for short periods of time up to 460 rpm achieving 750 HP. The TRITONE, built several years after the ARGO, received a new engine, the FIAT MEX 328R, an 8-cylinder diesel engine capable of generating 1200 HP at 450 rpm.

The surface speed of the ARGO class was around 14 knots on the surface and 8 knots submerged. The TRITONE maintained the same submerged speed, while surface speed was increased to 16 knots. After intense use, the diesel engines were prone to failures and required extensive maintenance. The limited speed of the ARGO was not a great factor, but in bad weather the engines’ intake valve, situated just above the engines on the deck instead of inside the cunning tower as in foreign design, would easily flood.

In general, as for most Italian submarines, the surface speed of all the ARGO and TRITONE was very limited and could not be improved with the installation of new engines. A German type VII A submarine, smaller than the ARGO, could reach 17 knots versus the 14 of the Italian boats.

Electric Motors

Both classes received electric motors produced by the C.R.D.A. Those installed on the ARGO produced 400 HP each (300 HP under normal conditions and 400 HP for brief periods of time). The ones installed on the TRITONE appear to have been similar in performance, but it is not sure if they were the same model.

These motors could operate at 45, 90 and 180 volts. The maximum output was obtained running 180 volts and 330 RPM. When not in use for propulsion, the electric motors could be used to generate D.C. (direct current) to recharge the batteries.

Transmission Shaft

Each diesel engine was connected “in line” with the corresponding electric motor via a gear joint. Another gear joint connected the electric motor to the propeller shaft. During normal diesel operation, the electric motor would rotate freely. During electric propulsion, the first joint was disconnected, thus freeing the diesel engine. During the recharging of the batteries, the second joint was disconnected, leaving the diesel engine to drive the electric motor at a fixed predetermined speed.

Batteries

On both classes there were two holds capable of holding 52 batteries each. On the ARGO, each cell weighed about 750 kg each. The total weight of all cells was 78 tons. The batteries could deliver 4,750 amps in one hour, 7,050 amps in three (2,350 amps/hour), and 9,720 amps in twenty hours (485 amps/hour). These are performances identical to the ARGO and TRITONE class.

Each cell was made of multiple positive and negative plates made of lead, each with common terminals, separated by insulators. The plates were immersed in an electrolyte solution made of pure water (distilled water) and pure sulfuric acid with a specific gravity of around 1.25 when fully charged. Each cell produced approximately two volts and was permanently wired in series. Each of the two battery groups could be operated independently or in parallel. On the ARGO and TRITONE each battery group was divided into two busses, each composed of 26 cells (26 x 2 volts = 52 volts).



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