WesWorld

Rangefinder Director RD Mk.I
This is a five man unit, in the front area sits, from right to left, Spotting Officer, Control Officer and the Rate Officer. All has his own binocular sight mounted in the front bulkhead, the Control Officer having his own telescope sight as well. Aft of them and slightly higher are the two Rangefinder Layers. They operate the 7m rangefinder and two roof periscopes to monitor the ships pitch and roll. The information is transmitted mechanically to the Transmitting Station directly below which is equipped with a Fire Control Clock (FCC), an analogue mechanical computer to determine the target positions and the likely firing solution. No plot is kept however in destroyer sized vessels, cruisers and battleships having a plot tracking capability and Director Controlled Fire so the Control Officer could fire all guns at once. The elevation and bearing is then transmitted to each gun mount and the layers follow the pointer dial on the mount. For AA firing a Fuse Clock is used, the Control Officers binocular sight having a ring sight, from this he estimates the height of the aircraft. The Fuse clock then gave the firing instructions to the guns like the FCC.
The RD Mk.I is fitted to the Mendoza Class destroyers1933 Class destroyers, Intrepida Class torpedo boats (5m rangefinder), the refitted 950 ton destroyers (5m rangefinder) and two each on the cruisers General Pueyrredon and General San Martin.

Rangefinder Director RD Mk.II
This simplified Mk.I is manned by three men, two Rangefinder Layers and the Spotting Officer with his own telescope sight. A 5m rangefinder is carried. The information is transmitted mechanically to the Transmitting Station directly below which is equipped with a Fire Control Clock (FCC), an analogue mechanical computer to determine the target positions and the likely firing solution and no plot is kept. No Fuse Clock is normally fitted with this system.
The RD Mk.II is so far only fitted to the two Los Andes Class gunboats and one aboard the General San Martin linked to a Fuse Clock only for AA barrage fire.

Rangefinder R Mk.V
A basic manual trained and elevated 3.5m rangefinder with three operators and linked to basic FCC to plot a basic firing solution without gun mount pointers. Fitted to the Chaco Class and the 1914 and 1916 destroyer classes. The smaller 1m R Mk.VI is fitted to some 37mm quadruple mounts.

HACS Mk.10
This modern High Angle Control System has been developed alongside the 115mm DP mount to give much better AA fire control. Three men operate the system, two Rangefinder Layers and a Control Officer who has central control of all the Heavy AA guns and quadruple 37mm mounts. A 3.5m rangefinder is mounted. Two gyros measure the target angular speed and this along with the range is fed electronically to the Transmitting Station directly below which is equipped with an Estimator Fuse Clock (EFC). The EFC is a modernised Fuse Clock which transmits the data to each gun mount. Such a system is very complex and as yet untried and many problems have yet to be solved with the system which is among the most advanced in the world.
Currently being fitted to the 1933 Class destroyers, the destroyer Cordoba (system trials ship) and the refitted Atantean cruisers (a full Transmitting Station with an FCC is fitted for surface actions) and eventually on the Chaco AA Escort variant.

Other systems
The Libertad and Capitan Gascon currently are fitted with three standard US rangefinders. The proposed modernisation would replace these with a RD Mk.III (a seven man version of the Mk.I with a better FCC and an 11m rangefinder), three RD Mk.I, one 15m rangefinder (atop the RD Mk.III) and five HACS Mk.10.

Patagonia and Pampas have standard Italian LA and HA directors.

Veinticinco de Mayo and Almirante Brown also have standard Italian directors and one HACS Mk10 aft with the older Fuse Clock.

Heroina and Sarandi are fitted with standard Italian rangefinders and directors.