Gibraltar Straits

The Gibraltar Strait is a narrow passage connecting the Mediterranean Sea with the Atlantic Ocean and separates northern Africa from Gibraltar and Spain on the southernmost point of the Iberian Peninsula. The strait is about 40 miles long and varies in width from about 9 to 24 miles. A continuous current enters from the Atlantic Ocean to replace water that is evaporated from the Mediterranean Sea, and tidal currents ebb and flow along the European and African coasts. More information on currents can be found in the West Coasts of Spain & Portugal Pilot (NP670) and the Strait of Gibraltar-surface &sub-surface water movements (NP629)

For more detailed tidal and current chart go to International Wave Atlas

Although Gibraltar is commonly thought to be the southernmost point on the Iberian Peninsula, Punta de Tarifa with its small marina is the furthest point south, located about 17 miles to the south-west. Tarifa does not have any yacht berths but is an important naval and ferry harbour. Gibraltar is still an important naval and commercial harbour and despite the emergence of the European Union is still considered politically and economically crucial. At present Gibraltar has three marinas all with good facilities.

Most marine vessels using the Straits must strictly obey the traffic separation scheme though smaller craft and coastal traffic can use the inshore lanes. For vessels with limited power close attention to the tidal streams and currents must be studied to maximise the use of nature’s forces. Vessels entering the Mediterranean use the southern lane and those heading for the Atlantic use the northern lane. Numerous ferries run across the Strait from Spain and Gibraltar to Morocco.

Surface water flow through the straits can be up to 2 knots east going and spring tides can reach 3 knots so for a slower yacht or one under sail and beating the timely arrival for a transit of the straits can either save or lose a great deal of sea time, and, especially in a levanter, the effect of wind over tide could make for difficult sea conditions.

There is a permanent easterly current which sets through the straits to compensate for the sea water which is lost from the Mediterranean through evaporation. The currents effect varies from 1 knot close inshore to about 2 knots in the centre of the straits. This though is not an exact science as temperature effects the rate of evaporation, and therefore the amount of water flow needed to replace this loss. Flow rates are stronger towards the centre of the channel. Tidal streams need to be adjusted for springs or neaps. Then a prolonged easterly or westerly wind can affect the overall flow predictions and as mentioned a wind over tide and/or current could make an anticipated easy transit a little more difficult! Is this a good time to mention there could be tidal races closer in shore?
There are many articles and publications on the best way to transit the straits of Gibraltar, one of which is Colin Thomas’s Straits Sailing Handbook. For me when I did it, it was all about timing, the satisfaction of arriving at the optimum moment to take advantage of nature and pick up 5 knots for free is very satisfying.

The eastern end of the Strait of Gibraltar is flanked by the Pillars of Hercules. The strait has long been stategically important, from the Carthaginians who blockaded it in the 4th century BC and controlled trade out of the Mediterranean, or the Spanish and Moorish forces who fought for control of it in the 8th to 15th centuries, up to the British who have used their base in Gibraltar to strengthen their naval position in several wars since the beginning of the 18th century. For more information click here