with much breakage of the road wheel axles. Renault YS 2 The Renault YS 2 was an artillery observation vehicle with advanced telemetric optics, including a rangefinder turret. On 20 July 1936 it was decided by the Artillery to acquire such a type, called the voiture blindée tous terrains d'observation d'artillerie. On 11 August Renault was contacted to build a full scale wooden mock-up of a vehicle capable of accommodating the ER26 ter and R14 radio set, a large number of telephone cable connections and on top an optical rangefinder turret with a base of 160 centimetres. The Renault tank design bureau estimated that such a mock-up could be created for the negligible sum of just 6500 French franc and thus on 21 September made the counteroffer to rebuild one of the YS prototypes for ₣ 195,000, apart from supplying the mock-up for ₣ 9500. However, the ministry of defence refused this offer, just ordering the mock-up on 12 October. However, on 5 November Jean Restany, head of the Renault design bureau, decided to rebuild the prototype anyway. On 26 January 1937 the rangefinder was received, but it proved, with a width of 160 centimetres, simply too wide for a chassis that itself was no wider than 170 centimetres, though an attempt was made to place it in a wooden dummy turret. On 2 April a commission of artillery officers visited Renault and these suggested to use the smaller standard rangefinder used by machine-gun units that had a base of 125 centimetres. This was built in a steel cupola, that also featured a central pair of binoculars and binocular diascopes at the sides and back, that could be protected by armoured shutters. On 22 June Renault offered to sell this vehicle for the discount price of ₣ 150,000 (mock-up included). On 31 July the Army agreed; the contract was signed on 7 October 1937. The vehicle, N° 58993, had already been sent on 8 August and was for field tests assigned to the 309e RATTT (Régiment d'Artillerie de Tracteurs Tous Terrains). Though the Atelier de Rueil in the Spring of 1938 began to study the possibility of fitting an improved turret, no further YS 2s were ordered, despite a continued demand for such vehicles: the Renault YS 2 was considered rather mediocre. ZT 4 On 9 October 1936, 21 Renault ZT4s, a tropical version with improved cooling, were ordered for