September 1940, the Maletti Group got lost leaving Sidi Omar, disappeared and had to be found by aircraft. In spring and summer the days are miserably hot and the nights very cold. The Sirocco ( or ), a hot desert wind, blows clouds of fine sand, which reduce visibility to a few metres and coat eyes, lungs, machinery, food and equipment; motor vehicles and aircraft need special oil filters and the barren terrain means that supplies for military operations have to be transported from outside. German engines tended to overheat and the life of their tanks' engines fell from to and this problem was made worse by the lack of standardized spare parts for the German and Italian motor types. Supply Axis Italian supply shipments to Libya went about west around Sicily, then approached the coast of Tunisia before going on to Tripoli, in order to avoid interference from the British aircraft, ships and submarines based at Malta. In Africa, supplies had to be hauled huge distances by road or in small consignments by coaster. The distance from Tripoli to Benghazi was about and to El Alamein was . A third of the Italian merchant marine was in ships berthed in British-controlled ports and was interned after Italy declared war. By September 1942 half of the remainder had been sunk, although much was replaced by new shipbuilding, salvage and transfers of German ships. From June 1940 to May 1943, 16 per cent of supply shipments were sunk. Tobruk was pressed into use in June 1942 but Allied bombing and its long approach route led this effort to be abandoned in August. The Germans assumed that the maximum distance a motorised army could operate from its base was but on average about a third of Axis lorries were unserviceable and 35–50 per cent of the fuel deliveries were consumed transporting the remainder to the front. Fuel oil shortages in Italy, the small size of the ports in Libya and the need to meet civilian demand, required the inefficient dispatch of large numbers of small convoys. (OKH, German army high command) concluded that German forces in Libya could not be supplied for a decisive offensive unless Italian forces were withdrawn to Italy, which was politically impossible. British The geographical position of Italy made it possible for it to close the Mediterranean if war came and force the Mediterranean Fleet based in Egypt