The Beira Patrol was supposed to stop Rhodesia, which had declared unilateral independence from the UK getting oil, now I have read the Wikipedia entry on the patrol and it sounds intense but take it from me we didn't stop very much getting to Rhodesia. In fact it was quite easy for ships to hug the coast inside international waters and we couldn't touch them, the only ship I remember stopping was one which let us to exercise the boarding party.
We hit heavy weather on the journey around the Cape and it separated the boys from the men, the Tartar had two small 'wings' or stabilizers on either side of the hull which could be deployed in rough weather, but when goffers came over the bows we had to cling on regardless. We met up with RFA Resurgent to top up with supplies for the many weeks ahead at sea, at least six by all accounts, HMS Hermione was also on patrol but we were only to see her occasionally for a sporting event called 'The Beira Bucket'. This was literally an old bucket which went to the winners of several contests which could be held at sea or on flight decks, tugs of war, deck hockey, volley ball, etc. needless to say being the unsporting type I was not fazed by these antics and kept a low profile or was on watch.