The Offshore Voyaging Reference Site

Coastal Passages, Part 2—Rounding Headlands

Tide at Raz De Sein © C. Speedie/Wave Action

Experienced sailors know that rounding tidal headlands must be taken seriously—there are many issues that need to be factored in to see us safely and successfully around them.

Tide Races

Tide races are not uniformly alike. Some occur over large areas, others are very localised. At some sites conditions may (in general) not be too bad, except for around small shoal patches or reefs where conditions will likely be significantly worse.

Some races run close to headlands, whereas others have a calm patch close inshore, especially in settled conditions and offshore winds—a so-called inshore passage—sometimes (even) with a back eddy to assist us when the tide is against us further out.

In many cases a race will move during the tidal cycle to either side of the headland, so knowledge of how this will pan out will enable us to plan our course to avoid the worst of the overfalls generated by strong tidal streams and shallow water.

Tidal sets in the vicinity of headlands may change direction dramatically over the course of a tidal cycle, making it important to be aware of our position at all times, and so avoid being set on to dangers.

Therefore, studying the tidal charts in Reeds (or your preferred pilot book) along this passage is a necessity—with care and attention at the planning stage and good timekeeping we’ll make our own luck and some fast passages.

Whatever the variables, one thing does not change: the need to be in the right place at the right time. Don’t be complacent about this—double check your calculations, always!

How To Manage Them

Let’s dig into the details of how to round tidal headlands safely and efficiently:

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Dick Stevenson

Hi Colin,
Wonderful read and wise advice. Brings back many a cross-my-fingers caus’ we-are-going-for-it moment where I hope I got the timing/weather/charting right because changing one’s mind quickly becomes not an option.
Sometimes these roundings are quickly over and you just ride the roller coaster, but, at times, one is at the effect of these currents for longer periods. I find, at the helm, that, for me, a visual, preferably a range, is often the only thing that keeps me oriented: I am thinking of the Channel Islands to Cherbourg and going into Ushant, both prolonged exposure to strong currents (and were exponentially unlike anywhere else in in the world that I have experienced). Both times I distinctly remember the somewhat out-of-body experience of Ginger telling me course over ground data while I am steering a compass course fully 40 degrees at variance with her communication. In the rushing and tumult holding onto a visual range grounded me in a way that instruments (or common sense) did not.
My best, Dick Stevenson, s/v Alchemy

Maxime Gérardin

Here’s a good video of the “Solitaire du Figaro” fleet (not) passing the Alderney Race, two weeks ago, in fair weather:

The video only shows the beginning of the tidal stream, not its maximum speed. The “tidal coefficient” (a french metric, more or less proportional to the tidal range and to the stream speeds) was 82 that day, which is slightly above a mean tide (70), but not that much. Let’s add that the race is 8NM wide, that the stream further from Alderney is at least as strong as along its coast, and that although the ocean swell does not directly enter the race, waves have dozens of miles of open water to form, from both directions, before they meet the stronger stream.

Maxime Gérardin

Hi Colin,
thank you for having read “average” instead of “mean” in my previous message 🙂
I had a similar experience in this race : no wind at all (we received a weather forecast by VHF while in the race, it said that the station at the cap de la Hague was measuring 0 kts), 8 kts of tide, according to the stream tables, resulting in a 8 kts headwind, allowing us to sail upwind and display more than 12 kts, steadily, on the GPS!
That said, I never saw the place with some wind against the tide.

Ernest E Vogelsinger

I will always remember my first tidal training week at the Solent – it was a real eye-opener when we found that the target spot we were aiming for was almost abeam. And I also remember the my first try at anchoring in a tidal stream when we learned that the “Med-style” “bow-into-the-wind” approach will give you a harsh swing around once the anchor gets hold 😉
It is as you say – sailors who are used to roam in almost tidal (or current-) free regions should be very aware of the huge differences. It is a completely different game – but always fun to play it, IMHO.

Dick Stevenson

Hi Colin
You give me opportunity to display what some unsophisticated souls call my pedantic side. I know exactly what you mean in what you wrote, but at times, the devil is in the details and the nuances.
You mention fishing vessels going from marker to marker as having right of way. Now, I generally try to stay out of the way of any vessel earning their living on the water as I am just a recreational visitor and generally have no time pressure etc.
But as for what Colregs actually says, and I am far from any expert, I have always understood that fishing vessels constrained in their maneuverability (actively fishing with nets, lines trawls etc.) are the stand-on vessel. I would suspect that a fishing vessel going from marker to marker is not restrained in ability to maneuver and would therefore not be a stand-on vessel in a crossing situation merely by being a fishing vessel.
I will continue to display my picky side by noting that, I believe, “right of way” is an expression not used at all in Colregs. You are either the stand-on or give-way vessel. I have always understood the reasoning for this is that Colregs does not want any vessel to experience itself as privileged (as having the Right of Way): we are all responsible in a crossing situation and both sides must do what is necessary to avoid collision.
Those who actually know about these things, please weigh in.
My best, Dick Stevenson, s/v Alchemy

Eric Klem

Hi Colin,

Headlands are definitely a challenge and one your area of the world is known for. The only thing that I would add is that it can be a huge help to learn to read the water. Probably the most basic aspect that I find many people are unaware of is how the boats steering will be affected by the water. Once you get used to it, you can see exactly which direction each little current line will turn your boat and you can get to the point where you can steer a relatively straight line in a proactive way. More advanced would be actually picking the line to be as fast and efficient as possible. In shallow water with a lot of current, the water surface will tell you a lot about the bottom. And if you really want to push the limits with headlands and rivers, riding eddies up behind them and knowing how to get in and out of eddies with big eddy fences is a useful skill. I am not sure the best way to learn this stuff but maybe whitewater paddling texts would be good? I learned it from 15 years of whitewater paddling.


Lee Corwin

Excellent read. Thank you.
Wonder if you can share advice on crossing bars. Sailboats are displacement hulls. Under sail or power you make find yourself with no steerage if there’s a onshore breeze and wave train as you cross a bar. Although my experience with this is mild compared with Portugal, Pacific Northwest or other locales it does catch you attention. Have had several occasions where transiting NJ coast while single or short handed and forecast has changed since initial departure from New England suggesting being in a protected harbor would be wise. It makes me nervous enough to just hunker down and keep on keeping on.

John Harries

Hi Lee,

I too have transited the NJ coast many times, and most of them out of season. My thinking is the same as yours: keep on going. Or to put it another way, I think the best wisdom on harbours with a bar is if in doubt, don’t. The big problem is that from seaward there is really no good way to access whether or not the bar is safe, so better not to find out that it isn’t the hard way.

Jesse Falsone

While transiting south along the NJ coast as Hurricane Lee lay offshore, we were surprised (and not in a good way) by the shoaling of the swell near the entrance to Atlantic City. I’ve made this passage many times, but always several miles offshore at this location. The wind was light at the time, and luckily it was daylight so we could see in front of us waves starting to break. We made a left turn in time to avoid those waves, but still within that shoaling one one or two crests that were a bit scary. Had we came this close in the dark we may have gotten ourselves into serious trouble as those breaking waves would’ve hit us broadside. I will always route us well offshore from this area in the future. The shoal waters off Cape May are arguably worse and far more expansive. Learned a big lesson.

John Harries

Hi Jesse,

Yes, that’s a nasty area that Phyllis and I have transited many times too. Thanks for sharing the lesson.

Dick Stevenson

Hi Lee,
I am no expert and only mildly experienced, so I will be curious what others have to say. I will point out that it is my take that assessing harbor entrances such as we encountered on the Atlantic coast of Portugal is almost impossible from the deck of a boat offshore. All you see are the backs of waves and not the gnarly front end. If language skills allow (and try anyway), I would call on ch 16 for local knowledge, but you will likely talk to a fisherman and not someone knowledgeable about sailboats. The guides may flag that certain well-known challenging entrances have some sort of flag system, especially those with active fishing fleets.
On the NJ coast, the last time I called the USCG for local knowledge, they refused information citing liability issues. One of the Tow Boat franchises were listening in and conveyed that there was a dredge mid channel after the entrance which was very helpful as it was thick fog and night. In fact, the Tow Boat franchises on the US east coast were extremely responsive to inlet conditions information, especially the often quickly changing conditions on the ICW.
Keep on keeping on is often the wisest choice, especially in the face of uncertainty. When I have decided that an entrance is workable: adequate depth to deal with the ups and downs of swells, not likely dangerous breaking waves, I ensure that all is buttoned up and that the companionway boards are in places and secured as being pooped might be a possibility. I then go in with enough speed to ensure control and forward movement. The worry is hitting bottom, but bouncing off the bottom worries me less than getting cross-wise in a breaking wave train.
I suspect I am conservative enough so all I have had to do was hold my breath and go for it and all has been fine.
My best, Dick Stevenson, s/v Alchemy

John Harries

Hi Dick,

I have to say that I’m always a bit leery of local knowledge for just the reason you state: you can’t know if the person your are talking to has relevant experience.

Lee Corwin

Thanks Dick. Agree with all you say. My big fear remains surfing at the same speed as the wave train. Have had this happen on a 46’ sailboat and 55’ sportfish with WOT. Fortunately in both occasions didn’t broach and the unresponsive helm was quite brief. Still once committed there’s often no turning back. Have been told putting the engine in reverse may work but I’m scared of blowing out the transmission so have never done this. Perhaps need more courage as for now if it’s a lee shore won’t cross a bar if it can be avoided. Even to the point of heading offshore and getting beat up.

John Harries

Hi Lee,

Yes, I really think that if it’s a lee shore inlet situation, the best bet is to get well offshore and heave-to. This is one of the reasons that I think every offshore sailboat should have a heave-to strategy: if we know we can “keep the sea” we are much less likely to do something stupid to get into port.


Dick Stevenson

Good morning John,
That is a really good point: the willingness to do the hard thing and hang out at sea. Sort of captures the essence of seamanship. Primarily coastal cruisers may have a harder time with this decision as they may have had less time at sea. I know it took me a while to realize that being at sea is often, perhaps usually, uncomfortable. However, it is only that, uncomfortable, and one can deal with uncomfortable.
My best, Dick Stevenson, s/v Alchemy

John Harries

Hi Dick,

I totally agree.

Rob Gill

Hi Lee,
Interested why a lee shore puts you off crossing a bar? A lee shore is a lee shore, but I would have thought an entirely separate decision from crossing a bar? Sure the seas created by the wind add something, but some of the most hazardous bar conditions are with the wind offshore – as when surfers seek an offshore wind with onshore swell for the perfect surf break, no? I found the main difficulty with an on-shore wind, is it makes the sea-swell more confused and harder to read.
Here in NZ many bars have a coastguard reporting service, where all vessels are encouraged to log a Transit Report before and then after to report safe passage. It is compulsory for every crew member to be wearing an approved lifejacket for bar transits, what ever the conditions. Our Coastguard (Coasties) will advise when bars are not safe to cross, but I don’t know of them advising on safe crossing. You have to be right there on the water to judge a notorious bar, for your boat – will it surf and run straight or nose dive and broach? Then the thousandth wave needs to be in front of mind – yes?
Br. Rob

John Harries

Hi Rob,

True. I guess I would class a bad onshore swell as making it a lee shore. Anyway, my point was that if there is any doubt about the situation, lee shores, bar, tide ebbing across the bar into a swell (worst case), whatever, staying offshore is safer. And I think that goes double if one is unfamiliar with the harbour and bar.

Or to put it another way, I will go to a lot of trouble and discomfort to avoid a bar entrance.