On the 2nd June the Rotary Club of Anstruther was treated to a very interesting illustrated talk by club member Ian McBain. Ian is Master of an oil exploration drill ship and chose as his topic ‘French Guyana Currents’. Not perhaps the most attention-grabbing headline, but in fact fascinating.

Off the French Guyana coast, the drill ship is exploring in 8,000 feet of water, with exploratory drill rods going down 34,000 feet below the seabed. With no anchors, the ship has to be held accurately on station by dynamic positioning with reference to satellite and other location signals. This means the very sophisticated, computer-controlled management of a series of positioning propulsion motors around the ship.

The strong ocean currents make the task difficult. We heard that these currents are a local phenomenon in the form of huge rotating loops of currents – 200 to 300 miles in diameter and to a depth of 300 feet or so. These can rotate at 5 knots or more and Ian showed a photograph of an impressive bow wave creaming away from the stationary! Vessel.

The size of the current loops could be seen from satellite and radar images. Equally notable was the local effect of water from the Amazon creating two very distinct colours in the sea.

The loops of currents are identified with names often taken from Classical times – Osiris, Zeus, Persephone, Medusa – but the effect is without doubt to make a difficult job very much more challenging. Apart from increasing the difficulty in keeping the ship on station, the currents working on 8,000 feet of drill rod must have quite an effect.

After a great many questions Ian was thanked with a very appreciative round of applause.