Aerial ranging assistance in early WW2: The Battle of the River Plate

After WWI cruisers and battleship started carrying planes. Quickly the standard became a catapulted seaplane. The recovery was tricky and seaplane maintenance was heavy due open sea operations.

They were used for long range observation and patrolling as the radar was in his infancy with a limited range. Some Navies also developed the procedures to enable those floatplanes to assist with ranging for long distance gun firing. 

The only usable air asset to the British Squadron based in the Falklands was the Fairey Seafox from HMS Ajax. The other Seafox was damaged. This explain the caution from the British side to commit and catapult the seaplane [1]p.63.  Fortunately Lt Lewin pilot and Lt Kearney observer the airplane crew were extensively trained thru several missions looking out for U-Boats along the coast of Brazil.

It is interesting to notice that communication to the float plane was using a different frequency depending of the type of mission. For the Royal Navy the wireless frequency for reconnaissance missions  was 230 kcs (KHz) and for spotting it was 3800 kcs (KHz). The longer wavelength (230 KHz) was enabling an extended range for transmission [2]p.128. Tuning in from one frequency to another was a complex process and unfortunately the information that the scouting Seafox was still on the 230 KHz channel was not passed to HMS Ajax communication team. The seaplane was catapulted around 6:40 and the frequency mismatch delayed the feedback from the scouting plane to 6:49am [2] p.150 and [1] p.76. There was further confusion between HMS Achilles and HMS Ajax burst which caused erroneous data to be fed back to the Dreyer tables of the HMS Ajax (mechanical firing computer). The full efficiency of the aerial scouting will start after 7:07am and last until 7:16 when the DKM Graf Spee broke the engagement with the 2 cruisers. During those 10 minutes most of the 20 6’ hits happened. Based on a firing cadence of 3 broadsides per minute it yield a success rate of ~5% at a range about 16 Kyards (15 km).

The scouting plane was also negating the effects of the smoke screens laid by the DKM Graf Spee. The changes in course were reported real time and the fire ranging were not interrupted.

The last mission for the Seafox was to inquire on the HMS Exeter status, as she was out of communication and inform the squadron commander Harwood that she survived the fight despite the hard hits. The successful recovery of the airplane made at 9:12am did not disrupt the pursuit of the DKM Graf Spee.

[1] Eric J. Grove (2000) The Price of Disobedience

Sutton Publishing ISBN 0750909277 / 9780750909273

[2] Dudley Pope (1956) The Battle of River Plate

McBooks Press ISBN 9781590130964


Getting started IOS Version 1.5.2

What is it about ?

DKM Graf Spee is a simulation of Naval Warfare. It will allow you to recreate the actual battle of the Rio de Plata and play also “what-if” scenario.

Historical Background


The game is turn based. Each turn duration is one minute and the turn start by orders for the Axis side and then orders for the Allied side.

How do I start to play?

From the “Home” screen,  choose one the scenario from the scrolling menu and read the short synopsis in the yellow tab. To load the scenario tap “Select”, At the prompt screen you will choose Continue (it will reset any game in progress)

We recommend the Scenario 1 (Historical Rio De Plata engagement), this way you can apply Commodore Harwood strategy.

The “Play Next” button will move screen to review the KriegsMarine main screen, another “Play Next” will provide the Allied (Royal Navy in this scenario) Main Screen.

The main screen contain weather information in a scrollable window (last 5 minutes of info).

The “Play Next” screen will start your units review and orders

For detailed information see  the following links:

Map, Speed, Heading and Steering

Boat and Crew Status

Gunnery Instructions

Torpedo Instructions

Observation Plane Instructions

The “Play Next” button will allow the review and orders to the 3 different units under your command in the scenario 1 (HMS Ajax, HMS Achilles and HMS Exeter).

After HMS Exeter all orders will be executed, including eventually gunnery resolution and torpedoes courses. The clock will tick one minute and the next turn will start.

Winning and Scoring

The goal of the allied Cruisers Squadron was to cause enough damage to the DKM Graf Spee to cripple her. Each boat has a point value which correspond to 100% of the operational value. The damage level required to cripple the DKM Graf Spee is 50% of the operational status. Your score (winning points) is the ratio of damages to the Graf Spee and total damages on your units.

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