The north wind decides: how Hurghada's wind and sea shape a technical dive

Most technical diving material treats the dive plan as if the surface did not exist: gas, decompression and bailout are planned in detail, and the boat is assumed to be waiting, flat and steady, at the end. In Hurghada that assumption rarely holds. The wind here blows from the north almost every day of the year, and the sea it builds decides more of a technical dive than the profile on the slate: whether long decompression can be spent on a fixed line or must be drifted under a delayed surface marker buoy (DSMB), how the boat finds a team that has been underwater for an hour or more, which sites are realistic on a given day, how cold the team gets on the ride home, and how hard the climb back aboard will be.

A wind that almost never changes direction

Climatology summaries agree on the direction. WeatherSpark's long-term averages give a predominant hourly wind direction "from the north throughout the year" ¹, and Windfinder's statistics for Hurghada Airport, based on observations since 2000, give an annual dominant direction of north-north-west with an average speed of 12 knots (about 22 km/h) and average gusts of 22 knots (about 41 km/h) ².

Source: WeatherSpark ¹; km/h and knot values converted from the published miles-per-hour figures and rounded.

These are averages: individual days can be far windier or flat calm, gusts run well above the mean ², and data sets rank the months differently (some name June as the windiest). The table describes a pattern, not a forecast; the day's forecast and the captain's judgement come first.

From wind to waves

Wind becomes sea state through three factors acting together: wind speed, how long it blows and the distance of open water it blows over (the fetch). The National Ocean Service puts it plainly: "If strong winds blow for a long period of time but over a short fetch, no large waves form", and large waves occur "only when all three factors combine" ³.

For orientation, the Beaufort scale's probable open-sea wave heights are about 1 m at force 4 (around 13 kn), 2 m at force 5 (around 19 kn) and 3 m at force 6 (around 24 kn) ⁴. The Met Office notes that these values describe well-developed wind waves of the open sea ⁴; close to a reef or in the lee of an island the sea can be much smaller, and in channels and on exposed outer reefs it can be steeper and more confused.

The wind also drives the water: open-ocean surface currents are wind-driven ⁵, and around reefs and channels the coastline and tide shape them further. There is no general rule for a given site on a given day; that is local knowledge held by the crew and instructors who dive the area every week.

Fixed line or drifting deco

A technical dive needs a planned way back to the surface. Technical writer Simon Pridmore puts it simply: "Every dive plan should include a fixed ascent route — whether this is a shot line, an anchor line or a reef wall" ⁶. On a calm day in a sheltered spot, a team can often complete its stops on a shot or anchor line, in one place, with the boat nearby.

When the wind is up, that option narrows. A boat on a line in a building sea can snatch at its mooring, and a line moving with the boat is a poor reference for holding a stop. Many teams therefore leave the reef or wreck and complete decompression in open water under a DSMB, drifting with the water around them. The DSMB becomes the upline and the team's only signal to the surface: DAN describes it as a device that marks a diver's position, alerts boat traffic and can serve as "an upline to fulfill decompression obligations" for technical divers ⁷.

Drifting deco is normal and well practised, but its costs grow with the wind:

• Stop depth is harder to hold. With no wall or line, the team holds depth by buoyancy and the DSMB line alone. Small, constant corrections are needed for the whole of the decompression.
• The team spreads out. Pridmore notes that "a drifting DSMB ascent can make life hard for the surface supervisor and safety divers" ⁶; in current, ascending divers who do not stay together can end up widely separated.

DAN's deployment guidance applies in full: never clip the reel or spool to yourself during deployment, keep lines taut and away from the body, and carry an easily reachable cutting tool every time a DSMB is deployed ⁷. DAN also recommends a large DSMB, at least 1.8 m (6 ft), for "better visibility to surface support and other boats, especially in unfavorable seas", and notes that in technical diving colours can carry meaning, with yellow sometimes agreed as an emergency signal and a slate or notebook page attached to describe the problem ⁷.

Being found after an hour of deco

After a long drift the team may surface well away from where it entered. DAN's guidance on getting found is blunt: "Even a slight chop or swell can make a diver on the surface very difficult to see" ⁸.

The same guidance recommends carrying both visual and audible signals ⁸⁹: a large, brightly coloured DSMB fully inflated, a signal mirror, a light or strobe, and a whistle or a louder air-powered horn, noting that wind can carry the sound of a whistle away ⁸. It also mentions electronic options, such as waterproof marine radios with GPS that send a position alert to nearby vessels ⁸. Divers should stay together: groups are easier to spot than individuals ⁸.

On the boat, DAN lists continuous lookout, binoculars and regular roll calls, plus a briefing on what to do on surfacing away from the boat ⁸. For a technical dive the briefing should also cover run time, the DSMB colour code and what the boat does if it loses sight of the buoy. Pridmore's warning is worth repeating: "Dives that began in blue skies and flat, calm waters have ended three hours later in raging seas and driving rain" ⁶. The surface plan has to cover the sea that may exist at the end of the dive, not the one at the start.

Wind, cooling and decompression

Hurghada's water is warm: WeatherSpark's averages range from about 22 °C (72 °F) in March, the coolest month, to about 28 °C (82 °F) in August ¹. Over a long decompression even warm water draws heat away, and the wind adds a second problem once out of it.

Evaporation from wet skin and a wet suit takes heat from the body ¹⁰. DAN notes that "a wind-breaking layer of clothing can do a great deal to preserve heat on a windy day", and describes the classic picture of a diver huddled in a towel, still in a wet suit, in a breeze, losing fine motor control ¹⁰. For mild hypothermia, the advice is to replace damp layers and dry the skin before adding dry, wind-proof clothing ¹⁰.

Thermal status also matters for decompression itself. In DAN's review of the factors that affect decompression stress, Dr Neal Pollock recommends "maintaining a neutral thermal status during the descent and bottom phases — certainly avoiding unnecessary overheating — and trying to achieve a mild warm status without high-intensity exercise during ascent" ¹¹. A diver who gets cold during long stops may eliminate inert gas less efficiently. The same article warns in the other direction after the dive: "Postdive warming can increase DCS risk. Taking a hot shower or getting into a hot tub will decrease the tissue solubility for inert gas and can promote bubble formation" ¹¹.

The practical balance on a windy day is to stay comfortably warm during decompression (adequate exposure protection for the total dive time, not just the bottom phase), then, after surfacing, get out of the wind, dry off and dress warmly, rather than jumping straight into a hot shower.

The climb back aboard

The final exertion of a technical dive often happens in the worst place: at the ladder, in a swell, with a twinset and stages, minutes after a long decompression. Pollock's review notes that light exercise during the ascent and stop phases can help inert gas elimination, but that "high-intensity exercise and exercise involving high joint forces should be avoided before and after dives" ¹¹. Hauling heavy equipment up a moving ladder is exactly that kind of effort.

Common-sense measures reduce it: hand stages up to the crew first; where the boat allows, remove the twinset or rebreather in the water and have it lifted aboard; time the climb with the boat's movement and do not rush. The method depends on the boat and crew and should be agreed in the briefing, not improvised at the surface.

Seasickness on a windy day

A rough boat ride can compromise a technical dive before it starts. DAN advises choosing the largest, most stable boat available, avoiding alcohol and heavy meals the day before, and never diving on a medication used for the first time, as some anti-nausea medicines cause drowsiness ¹². It also notes that one prescription option affects the central nervous system and that its withdrawal symptoms can resemble decompression sickness ¹². If vomiting happens underwater, DAN advises keeping the primary regulator in the mouth and vomiting through it, with the spare second stage kept handy ¹². A diver prone to seasickness should discuss medication with a dive physician or DAN well before the trip.

Sheltered sites and the decision of the day

Because the wind direction is so consistent, the most useful shelter is usually the south side of a reef or island, in its lee. Exposure varies sharply from site to site. Abu Nuhas, the wreck reef near the Strait of Gubal, is described as having an "exposed northerly aspect" ¹³, and Careless Reef, an isolated reef offshore from Hurghada, is described as a site where "weather conditions often make the exposed site difficult or impossible to dive" ¹⁴.

For a technical team, site choice on a windy day decides whether a fixed line is possible, how far the drift may run and how hard the pick-up will be. Some days the right answer is a different site, a shorter plan or no technical dive at all.

Checklist: before a tech dive on a windy Hurghada day

• Check the forecast for wind speed and gusts for the whole dive window, including the expected surfacing time.
• Agree with the captain whether decompression will be on a fixed line or drifting under a DSMB, and where the boat will be during the stops.
• Brief the DSMB colour code, the "something is wrong" signal, the expected run time and the boat's search plan if it loses sight of the buoy.
• Carry a large (at least 1.8 m) DSMB, a reel or spool you can deploy in current, a cutting tool, a whistle or louder horn, a mirror and a light; consider an electronic locator.
• Choose exposure protection for the total dive time, including long stops, not just the bottom phase.
• Have a wind-proof layer, a towel and dry clothes ready for after the dive; avoid hot showers immediately after.
• Agree how cylinders and units will be handed up and how divers will climb aboard in a swell.
• If prone to seasickness, test any medication well before the trip and seek advice from a dive physician or DAN.
• Accept that the right decision may be a sheltered site, a shorter plan or postponing the dive.

Key takeaways

• Hurghada's wind blows mainly from the north all year, strongest from late May to early October ¹; exposed sites feel it far more than sheltered ones ¹³¹⁴.
• On windy days, drifting decompression under a DSMB is common, but it makes holding depth, staying together and being found harder ⁷; some technical writers argue it should be a fallback, not the primary plan ⁶.
• Visual and audible signalling devices and a clear boat procedure are essential, because a diver in chop is hard to see ⁸.
• Stay mildly warm during decompression, get out of the wind after surfacing and avoid hot showers or heavy exertion straight after the dive ¹⁰¹¹.