Beira Patrol and farewell to the haversine

The Beira Patrol – History
Between 1966 and 1975, the Royal Navy, primarily, conducted one of the more unusual blockades of modern history–a maritime-intercept operation that became known as the “Beira patrol.” The Royal Navy and Air Force monitored shipping in the Mozambique Channel in an attempt to ensure that no oil reached landlocked Southern Rhodesia (today Zimbabwe) via the port of Beira, in the Portuguese colony of Mozambique. Although the military executed these operations skillfully, Britain’s overall oil embargo against Rhodesia, which had unilaterally declared its independence in 1965, failed.

Warning : This chapter contains boring advanced spherical trigonometry techniques

RFA Fort Rosalie (A186) was an armament stores carrier of the Royal Fleet Auxiliary. She was built by United Shipyards, Montreal commissioned in 1945, initially completed as a stores ship but converted to an armament stores issuing ship at Portsmouth 1947/8.

This should really be two chapters, but as it concerns the same vessel, I have combined the two into one.

The Far East

The RFA Fort Rosalie was attached to Royal Naval Base Singapore this was before PM Wilson pulled us out and the base was handed over to ANZAC, I served on her for 18 months, they could not get me off her, being the Navigation / Ops officer of a vessel which rarely went to sea was a good number. Most of my time was spent arranging parties as the Wardroom Social Secretary or playing golf / squash / dinghy sailing at HMS Terror. One advantage of being stationed abroad, was as a civilian, if one was out of the country for a financial year, one could claim back income tax for that year. Something naval personnel and MOD civil servants could not. A matter of great contention.

Our maximum speed was 10 knots, also being the critical RPM of the Leander Frigates which made up the Far East fleet in those days, this made station keeping during RAS (replenishment at sea), exercises impossible. Speeds slower than 10 knots were also not possible, so we spent most of the time not doing anything. We were one part of the two British fleet along with one Australian and one New Zealand sent to HK for the two to three week Christmas period, otherwise we stayed on our buoy off RNAD (Royal Navy Armaments Depot, NATO required, maybe demanded, an ammunition supply vessel in the Far East, we were that in spite of the fact we were pretty useless. On one occasion the Captain stated he was bored and sent me off as ops officer to naval HQ to see FLOGO (fleet logistics officer), to “get us sent somewhere”, FLOGO said he would put us down for two weeks at Penang. I said that I thought two weeks might be too long, could we come back if we do not like it? He replied, “yes, just send a signal”. We spent four days at Penang before returning to our home off RNAD.

Then we were sent to join the Beira Patrol via Gan (we stopped there for a jolly), an RAF staging post (UK to Singapore) in the Maldives

The Beira Patrol

We were based at Mombasa, our job was to toodle off down the coast and join the patrol vessel(s) stationed way off Beira, delivering heavy mail, fresh fruit and vegetables, every two weeks or so. Light mail was parachuted in by the RAF.

The vessels stationed off Beira to relieve the boredom held internship sporting competitions, named the Beira Bucket after the trophy.

On one occasion it took place on board the Fort Rosalie I got chatting to the navigation officer of the frigate who wanted to know how I was always managed to be spot on the RV point at the usual time of 1200. when we had no long range radar to get a position off the land. I replied it was simple, I took sights of the Sun, Moon and Venus. He looked at me as if I was crazy, Venus? Yes I stated that it was a ‘morning star’ at present, the moon rather unreliable as it is fast moving and needs lots of corrections, but Venus is excellent, the best. If you pre calculate the azimuth and altitude of the planet, set your sextant and compass up, you will be able to see Venus, take a sight and obtain a position line, cross it with the Sun and you have a fix. I had him completely baffled, so much for RN Navigation training, extinct now due to GPS and other systems.

The calculation to work out the azimuth and altitude of a ‘heavenly body’ is long and complicated, but I did it simply and quickly using a scientific calculator. A TI-59 card programmable one in my case.

T!-59 Card programmable calculator
T!-59 Card programmable calculator with optional printer

I was one of the first people to realise the Marc St-Hilaire version of the spherical cosine formula could be ditched as using a scientific calculator, the pure cosine formula can be used. Marc St-Hilaire uses haversine (1-cosine/2) or (versine/2). ie half the versine. Cosine angles between 90 & 270 are negative, logarithms do not do negative, so haversine tables were produced to keep all angles positive. Using a calculator, the ‘normal’ more simple spherical cosine formula can be used as logs are not needed. Bye bye haversine

As I said i was one of the first to realize this and wrote learned articles on the subject to magazines and the Journal of the Royal Institute of Navigation. Hooray for Peter I hear you say or maybe no!

Below are the formulae used, in this case for an early (1986) non programmable calculator. Later developed for programmable calculators and computers, the latter written by me in BASIC, along with other marine programs.