for Rhodesia would soon arrive. Blockade Following the reports of Rhodesia defying the oil embargo by sea, the British felt pressure to take action and thus prove their commitment to sanctions. On 1 March, the Royal Navy established the Beira Patrol. As many nations had committed themselves to the policy of sanctions, it was required that the nationalities of any tankers carrying oil to Beira should be known. This was the task of and the escort forces HMS Rhyl, HMS Lowestoft and later . Stationed off Beira, directing it to prepare for intercept operations starting on 4 March. Consequently, left Mombasa on 1 March 1966 and was ordered to proceed to the Mozambique Channel to commence a surveillance patrol off Beira. On 6 March, early warning aircraft from the carrier began search operations in the Mozambique Channel. The frigate HMS Rhyl and a logistical support ship were soon added. On 28 Feb 1966 had sailed from Singapore on passage to Beira and remained on station until 10 May 1966 (being relieved by ), returning to Singapore on 10 May 1966. In 71 days Eagle flew 1,070 sorties, flying 600,000 miles, surveying 200,000 square miles daily, steaming a total of 30,000 miles. The patrol lasted until 1975. At any time, two British frigates or destroyers, with the support of land and carrier-based surveillance aircraft and auxiliary vessels, were committed to the patrol. Various British warships cruised the Mozambique Channel from Beira and checking on oil tankers heading for the port. As an example of such deployments, interrupted her passage out to Singapore to carry out a deployment on the Beira Patrol early in 1967. Initially, Royal Navy ships were to shadow and question Beira-bound tankers, and were only allowed to forcibly divert a tanker away after Britain obtained permission from its flag state. However, in the event that permission was granted, British warships were only allowed to demand it change course in the name of its flag state, and fire a shot across the bow if it did not work. The use of force was not authorised, and if the tanker absolutely refused to comply, the shadowing warship could take no more action and only follow it to within Mozambique's six-mile territorial limit. This meant that the tanker would be allowed to proceed unhindered to port. After an incident where the Greek tanker Joanna V was intercepted by , but as