There is a particular kind of nasty surprise that does not announce itself. The ferry passed half a mile off, you watched it go, you relaxed, and ninety seconds later a steep wall of water arrives from where the ferry used to be and tries to throw the kettle across the galley. Ferry wash is the most underestimated hazard a coastal cruiser meets in French waters, partly because it arrives after the danger seems to have passed, and partly because nobody warns you how big it can be from a fast craft.
Two different problems: displacement ferries and fast craft
It helps to separate ferries into two kinds, because they behave completely differently in the water.
A conventional displacement ferry on the cross-Channel routes pushes a large, long-period wash. It is heavy and it can rock you hard, but it is relatively predictable and you usually see it coming a long way off. Brittany Ferries runs the classic crossings such as Portsmouth to Caen, around six hours by day, with up to four crossings a day, and these big ships give you time to prepare.
The fast craft are a different animal. The high-speed catamaran wash is steeper, shorter and meaner than the wave from a displacement hull of similar size, and it can break unexpectedly over a small boat. Brittany Ferries' former Normandie Express, a high-speed catamaran on the Portsmouth to Cherbourg run, could carry passengers and vehicles at up to 42 knots. A wake thrown off at that speed reaches you fast and steep, and the documented hazard for small craft is real, with the Nautical Institute and others recording incidents of fast ferries endangering small boats.
Why the wash arrives late and steep
The geometry catches people out. A wake leaves the ship at an angle, fanning out behind, so the part of it that reaches you was generated when the ship was somewhere else, often well past your beam. That is why the sea looks settled as the ferry goes by and then a set of steep waves arrives a minute or two later from an angle that surprises you.
Two factors make a fast-craft wake dangerous out of proportion to its size:
- It is steep. A short, steep wave is far more likely to break, to slam, and to roll a small boat than a long, gentle swell of the same height.
- It often comes in a set, two or three close together, so just as you recover from the first one the second lands.
In confined water (a marina approach, a buoyed channel, the entrance to a river) the wash also reflects off walls and breakwaters and comes at you from two directions at once. That is where dinghies get swamped and unsecured gear goes over the side.
Where the high-speed routes run
If you cruise the Channel and the Brittany coast you will share water with fast craft and dense ferry traffic on the cross-Channel and Channel Island routes in particular. Cherbourg, Caen-Ouistreham, Saint-Malo, Roscoff and the routes to and from the Channel Islands are all busy. Many of these terminals sit at the head of a buoyed approach, which is precisely the confined water where wash is worst. If your passage takes you into Cherbourg from the north, the approach is shared with serious traffic; my notes on crossing the English Channel by boat cover the wider picture of timing your crossing to avoid the worst of it.
Ferries on a regular scheduled short crossing have a light reporting burden; they may only need to tell the coastguard, Dover or CROSS Gris-Nez, that they have departed. In other words they are moving on a tight commercial timetable and they are not going to slow down for you. The responsibility for staying upright in their wash is entirely yours.
The seamanship: how to take a wake
When you see a ferry, especially a fast craft, the work is not over when it passes. Brief the crew and prepare, then take the wash deliberately.
- Anticipate. Once you have identified a fast ferry, assume a wake is coming and keep watching the water in its track behind it, not just the ship itself.
- Turn to meet it. Take a steep wake on the bow, roughly 30 to 45 degrees off, not on the beam. Beam-on is how you get rolled and how everything below ends up on the cabin sole.
- Slow down. Reduce speed so the boat rises to the waves rather than driving into them and slamming.
- Secure the boat first. Anything loose on deck or in the galley becomes a missile. Close the washboards if it looks lively.
- Mind the crew. Tell people it is coming. A wake that merely annoys an experienced hand can put a guest over the side or into a winch.
A dinghy on a painter astern deserves a special thought. A steep wake can flip it or fill it; shorten the painter or get it close in before the wash arrives.
The night the dinghy nearly went
My own cautionary tale is small and stupid, which is what makes it useful. We were motoring gently into a Brittany approach channel late in the afternoon, dinghy on a long painter astern, washboards out, mugs of tea on the cockpit seat. A fast ferry crossed our stern half a mile off and I thought nothing of it. The first wave caught us on the quarter, the second broke into the dinghy and half filled it, and the painter snubbed hard enough to spin our stern through twenty degrees. Nothing was lost and nobody was hurt, but it was pure luck, not seamanship. Had the dinghy flipped it would have fouled the prop in a buoyed channel with a ferry route alongside, which is the start of a genuinely bad afternoon. Now I shorten the painter and clear the cockpit the moment I see a fast craft, every time, and I am almost boringly early about it.
In harbour and at anchor
You are not safe from wash just because you are tied up or anchored. In a marina approach the reflected wash can surge boats against pontoons and snatch lines. At anchor in a bay near a ferry route, a passing fast craft can set you rolling violently with no warning. When you choose an anchorage, look at the chart for the ferry lanes; a beautiful spot that sits beam-on to a fast-craft route will give you a miserable, lurching night. This is the same judgement you apply to swell and fetch when you weigh up anchoring versus a marina in France on cost and comfort.
Sharing the approaches with the professionals
Ferries are only one part of the professional traffic that owns the busy French approaches. Cherbourg, Saint-Malo, Roscoff and the Channel ports also see cargo ships, fishing fleets and, near the naval bases, warships. The discipline that keeps you safe in ferry wash is the same that keeps you safe everywhere: spot the big vessel early, work out what it is going to do, and make your own movements obvious. When you cross the dense streams of the shipping lanes off Ushant and the Casquets you apply exactly this thinking to merchant ships, and near Brest or Toulon you apply it to the unpredictable movements of submarine and warship traffic. A fast ferry is simply the version that gets you after it has gone past.
A short reality check
Fast ferries are not out to get you, and the crews are professional, but the physics is not on your side. A 42-knot catamaran cannot stop or slow for a yacht, the wake it throws is steep enough to break over a small boat, and that wake reaches you after the ship seems to have passed. Build the habit: spot the ferry, assume the wash, prepare the boat and crew, and meet it bow-on at reduced speed. Do that consistently and the worst a ferry will ever do is rock your coffee. Forget it once, beam-on, with the dinghy long and the washboards out, and you will remember why this article exists.
