Enemy actions near Tobruk on 11 April 1941 seemed to indicate that they planned an attack the next morning. General Lavarack took the threat seriously and had the 18th Brigade moved to be closer to the area between the 20th and 24th Brigades. The 18th Brigade was loaded on on vehicles to move them to the intersection of the El Adem and Bardia roads. They were ready by the time the sky started to lighten. After seeing enemy tanks showing themselves, the Tobruk defenders realized that they needed to have their anti-tank guns forward. Keeping with the British practice of breaking up units for independent use, they sent a troop from the 3rd. RHA to support the area expected to be attacked, but they arrived too late.
When the day started on 12 April, the wind was blowing sand. One company of the 2/17th Battalion could see enemy troops about a quarter mile away. They were in good defensive positions. The company was reinforced by seven anti-tank guns from the 3rd RHA. Holes had been made in the wire, so men went out to repair them, while lying on their backs. A soldier with w Bren gun fired back at the enemy and covered the repairs. The Bren gunner was able to silence the enemy machine guns. As the threat subsided, the 18th Brigade was pulled back. General Lavarack had decided that it took too long to move the 18th Brigade, so he wanted the three battalions deployed at strategic sites.
One good thing was that the RAF was able to constantly hit the enemy troops despite their shortage of aircraft and the necessity to pull back from forward air fields. The men at Tobruk could not see the bombing raids, but the enemy were very aware of them. The German diary said that the British controlled the air over the area. The airfield at Tobruk hosted twelve Hurricane fighters. As of 12 April, the German air attacks on Tobruk grew in intensity.
There was a significant number of ships in the Tobruk harbor. They enemy assumed that they were preparing to evacuate the troops in Tobruk. During 12 April, enemy aircraft attacked the ships, but was not able to damage any, as they were being protected by heavy anti-aircraft fire. This is based on the account in Vol.III of the Australian Official History.