General Lavarack had decided that what they would have to do is to "hold Tobruk against an encircling force". There was no possibility of stopping Rommel from advancing past Tobruk. The 9th Australian Division was now in Tobruk, as of 10 April 1941. Tobruk sent out patrols from the 1/King's Dragoon Guards and the 18th Lancers (Indian cavalry). One such patrol from the 18th Lancers drove out to the escarpment where they could see the Derna road.
Quite soon in the morning, a sand storm blew up and reduced visibility. The 10th was the worst day that the Australians had seen so far in the desert. The trenches quickly filled with sand, so the men stayed busy shoveling sand, only to see them refill again.
The perimeter being defended at Tobruk was some 28 miles long. The distance across was about 17 miles. The average radius of the circle was about 9 miles. The harbor at Tobruk was said to be the best in the part of North Africa that had been controlled by Italy. On 10 April, the harbor was partially blocked by some ships that had sank.
The perimeter was held by three Australian brigades, but only two battalions per brigade were in the line. Each brigade was backed by a field artillery regiment. The ultimate plan was to have central control of all the artillery in Tobruk, but until that was implemented, the regiments were brigade control.
Early in the morning, a German force could be seen driving towards Tobruk. They had seven light tanks, two companies from the machine gun battalion, and some field guns. They were apparently driving along the Derna road. They were immediately engaged by "bush artillery" and guns from the 51st Field Regiment. The Germans turned around, and then deployed their troops. Two platoons of British machine guns were called forward to engage the German troops. A few Germans turned to the south and then turned towards Tobruk, where they were engaged by another bush gun. Some German armored cars tried to find a way into Tobruk, but they were also engaged by bush guns. One of the guns was almost dangerous, but the other was more effective and was coached by a visiting senior British artillery officer. This is based on the account in Vol.III of the Australian Official History.