One warm October evening about ten years ago while I was working in Marbella I decided to reach the famous Rocca. You arrive by car in La Linea, on Spanish soil, to then cross the border to reach, passport in hand, British land joined to the Iberian Peninsula by an asphalt cordon, at landing runway times for the few aircraft to and from ‘Europe. I immediately go to the marina to look for the boats that will soon leave for the crossing, dreamy and curious, to steal a sensation, or just to feel like one of them.
Many years later I found myself leaving the port of Alcaidesa della Linea, aboard a Franchini 55, with Cecilia, Marco, the Skipper, and another friend. It was an ocean sailing course, but it was everyone’s first time. The tide calculation was good in Tarifa for 11, so at 9 we left the port, gymcana among the immense ships at anchor to enter the whirling and violent river between Europe and Africa, the mythical strait. Winds blow from east to west. With the Levanter you go out and with the Poniente you enter, more or less. The direction of the wind is not booked, therefore on the established departure date, one or two days could be added waiting waiting for the rotation in favor, while when you return from the Azores it is a lottery.
When you go out towards the west and the wind is from the east, and the current in your favor, the sensation is impressive; that 3 September was just like that, and we were sailing at 10 knots SOG with 3 knots of current and 40 of true wind, loved with only staysail. The turbulence is not scary, but the violence of the wind is striking, which due to the venturi effect, as it approaches Tarifa, increases by a force every two miles, in fact the wind blows over 30 knots for 340 days a year.
Every sailor can find on the web all the information necessary to plan a safe passage, however, we who have done it 5 times, 3 outbound and 2 inbound, and have searched the web, studied, questioned other sailors, talked to the captaincy , rated the tide tables etc. in the end we got a pretty precise idea to go by calculating with an acceptable approximation the delicate balance between tide, wind and current, to give you some practical advice that will come in handy when you find yourself excited to leave the moorings in Gibraltar or at the Alcaidesa marina, eager to enter the Atlantic.
Let’s start with the rules that are not editable:
- Exiting the Mediterranean is more complicated than entering, in the sense that the favorable tide windows are shorter than entering
- Enter the Mediterranean from the south and exit the north referring to the strait
- Always refer to the HW-GBR (Gibraltar maximum high tide), in other words you have to look up the time of the Gibraltar high tide and write it down, then you will understand why. Everything refers to the HW-GBR.
- SURFACE CURRENTS: on the north side +0.5 knots eastwards; to the south side + 1 eastbound node (this is a reason why getting in always helps)
- THE TIDAL CURRENT GOES FROM 2 TO 4 KNOTS, better be in favor.
- THE TIDAL CURRENT CHANGES EVERY 6 hours and 20 minutes, which are the minutes of tiredness.
Now let’s build a table that considers the parameters we really need:
Study the weather to have Levanter to exit and Poniente to enter. When you go out you are favored because you are at the mooring and you can plan almost perfectly. Entering when arriving from the Azores is just a matter of luck. Then we will see in detail how to do it in case we find ourselves in unfavorable conditions.
Report the calculation of our position to the HW-GBR, and evaluate the time it will take to reach Tarifa, the real passage whether you exit or enter.
C) SURFACE CURRENT
Always from +05 to +1 from west to east.
ENTER FROM SOUTH
HOURLY WINDOWS IN ENTRY:
FROM – 4 HOURS TO + 2 HOURS WITH RESPECT TO THE HIGH TIDE OF GIBRALTAR
In other words we have 6 hours of good current window in favor
HOURLY OUTPUT WINDOWS
FROM +2 +3 +4 HOURS WITH RESPECT TO THE HIGH TIDE OF GIBRALTAR (HW-GBR)
In other words, we have a maximum window of 2 to 4 hours to have current in favor.
Practical example in output:
For the day you have chosen the HW-GBR is at 12 noon and you are at the Gibraltar Line or pier. You must be at the Tarifa passage from 2 to 4 hours after departure, and you will have electricity in favor. The favorable current in Tarifa will be from 14 to 16, after it reverses.
Each tide chart will always bring you back the HW-GBR.
At the exit the surface current will be -0.5 from the north, which you will have to remove from the area current which will be favorable, maybe let’s say 2 to 3 knots that day. So roughly you will have 1.5 / 2.5 knots in favor, and with the wind in your favor you will be expelled from the Mediterranean like the Prosecco cap you have in the refrigerator.
To enter it is useful to have a longer time window, and the tide calculation is not difficult as it is possible to slow down the arrival and program it with current in favor. The wind, however, cannot be booked.
The first return with MB was easy, although nocturnal, with a current of 4 knots in favor and a tailwind. We entered at 10 knots of SOG of only genoa and the most delicate thing was the extreme attention to the ships in transit crossing the strait to enter the gulf west of the fortress.
The second return was really complicated. Only a large boat with a powerful engine and a millimeter tide calculation allowed us to enter. There was a strong east wind blowing up to 45 knots in Tarifa. Unmodifiable also by waiting 24 hours in the ocean because the following days 60 knots would blow in Tarifa. That was the window, it was necessary to try, also because turning the boat and succeeding would have been easy, but then, even if we stopped in a port like Barbate or Cadicz we would have had to wait for favorable conditions. We attempted the entry with 40/45 knots on the nose and 3 knots of current in favor. An insane condition, the worst ever in my experience of over 60,000 miles of sailing.
The outgoing wind wave trains collide with the strong incoming current creating a very rough sea vertically, with trains of 3 manageable and 2 unmanageable waves covering the deck, the spray hood and on two occasions beyond Ariel’s bimini, with a bow 2 meters high and a step like a great lady of the sea. We sailed at 6 knots of Log and 4 of SOG with 3 of current in favor with the engine at 2200 rpm (Volvo 145 horsepower). The journey of 12 exhausting miles took 3 hours, the worst, then after Tarifa the Grib gave us two forces less, or 8 to 6 Beaufort. Some parameters taken by studying with AIS the speed of a large motor boat and a contact with our weather router allowed us to continue. Indeed, the gradual decline after Tarifa made us fly at 7 knots SOG without changing attitude.We arrived at the passage of the Rocca with 10 knots of wind from the east; this makes us understand the Venturi effect! At point Banus, about thirty miles towards Marbella we moored in full calm….