The Chas Lap

The “Chas Lap” is the longest, burliest standard training swim one can do in the Aquatic Park vicinity.

(By standard, I mean: It is readily understood by a two- or three-word phrase in the men’s and women’s saunas at the South End Rowing Club.)

The Chas Lap touches, by definition, the western and eastern boundaries of the area in which it is acceptable for South End members to swim unescorted. There are bigger, burlier swims possible elsewhere in the Bay, but – and here’s the key – if you swim across the path of potential boat traffic, you must have an escort vessel. A Chas Lap can be done unescorted, and therefore requires far less planning.

Important Safety Caveats:

  • Never swim outside the Cove alone! You could get injured or killed, and no one would know, possibly for hours.
  • Avoid swimming outside the Cove later than mid-morning. Theoretically you should be safe from boat traffic by hugging the pier or breakwater, but there are always many more boats in the afternoon. The more boats in the area, the more potential for some rogue idiot boat driver to ruin your day.
  • Don’t attempt a Chas Lap unless you can successfully complete a RTFM (Round-Trip Fort Mason) against a flood on most days (more on this below).

Click the map to enlarge:

san francisco aquatic park

To complete a Chas Lap, swim out from the South End beach to the Opening. Then turn left and swim along the outside of Muni Pier to Fort Mason. Not just Pier 1 of Fort Mason (as for an RTFM), but all the way to the end of Pier 3 – the entrance to Gashouse Cove Marina. Then, swim all the way back to the Opening and keep heading east along the Breakwater to the Creakers (entrance to Hyde Street Harbor). Then back to the Opening and into the Beach.

Or, in SERC shorthand: Beach –> Opening –> Gashouse –> Opening –> Creakers –> Opening –> Beach. Shortest straight-line distance is 1.95 miles. Let’s call it 2.

Chas D.

The Chas Lap is named after South Ender Chas D., who didn’t exactly “invent” this route, but started swimming it so often that people started calling it a “Chas Lap.”

The challenge of a Chas Lap is that you’re swimming against the current twice – not just once, as in a vanilla RTFM. And the second time is at the end of your swim, when you’re probably already exhausted.

Chas Laps are best done on a flood tide – so you swim the longer stretch of head current (Opening to Gashouse) first, and the shorter stretch of head current (Creakers to Opening) last. I do not recommend trying to get all the way back from Gashouse on a rising ebb. The currents can increase faster than you expect, and you can get tired faster than you expect. If you have to be rescued, you will bring shame upon Chas, the South End… really, just about everyone.

The cove between Muni Pier and Fort Mason. Not sure if it has a name.
The cove between Muni Pier and Fort Mason. Not sure if it has a name. Photo credit: D. Ho.

Varieties of Chas Laps

In order of difficulty:

  • Double: twice back-and-forth along the line between Gashouse and Creakers. Returning to the beach between the first and second legs is not necessary.
  • Reverse: a Chas Lap on an ebb tide. Breakwater first, then Gashouse. Not recommended.
  • Fully Outside: a standard Chas Lap. Must swim outside Muni Pier on the way out, and outside the breakwater on the final stretch.
  • Inside: Swim outside Muni Pier on the way out. Then, if the current is too strong to finish the final stretch outside the breakwater, swim back along the inside for slacker water.
  • Under/Outside: It is substantially easier to make westward progress from the Opening on a flood tide, if you swim under Muni Pier until it curves around to the north (then cut across the cove to Fort Mason). Watch out for barnacles, though! Then on the final stretch, swim outside the breakwater.
  • Under/Inside: Under the pier on the way out; inside the breakwater on the final stretch. This route will drastically reduce the effect of the currents.
The Creakers. SS Jeremiah O'Brien in background.
The Creakers. SS Jeremiah O’Brien in background.

One last thing, and I’ll try to put this gently:

Do not try this unless you know what you are doing.

If you’ve never swum in the Bay before, try going to the Flag and back. If you get tired of running head-first into triathletes along the buoy line, try swimming around the Cove once. Then twice. If you get comfortable in the Cove, try swimming against an ebb down to the Creakers. If you master that, maybe try a RTFM. If you are a fast enough swimmer to get to Fort Mason against a flood on most days, only then should you consider attempting a Chas Lap.

Don’t swim alone. Always check the tide books. Use common sense. Don’t be an idiot.

The music of DRIVEN

[YouTube video]

[Narrator] Day breaks.

And almost miraculously, despite five hours of complete darkness and grueling conditions, Evan’s swim is still just on track to break the speed record.

But even though time is on his side, Evan’s will to push on teeters on the brink.

[Evan] I wasn’t motivated. There was no goal I had in mind — at least at night.

Really, there was just nothing else but: One stroke after another.

And then during the day, everything shifted a little bit.

There’s an unavoidable thing, with the sun coming up into the sky, and night turning into day. Life seems a little bit better.

I guess I thought to myself: Well, I made it to this point. I can’t really quit now. That would be ridiculous.

[Narrator] Evan doesn’t push on; he charges on.

[David Yudovin] If you’re motivated to make the swim, it’s going to work. If it’s deep in your heart, it will all fall into place.

[DRIVEN official website]

Launching the global Rules of Marathon Swimming

We’ve come a long way in four years.

“Evan’s Swim Blog” became “Freshwater Swimmer,” which finally became “Farther, Colder, Rougher.”

A mile became two; 5K became 10K; 10 miles became 24, round-Manhattan, Catalina, and an Ederle record. The SBCSA led to a Santa Cruz Island swim, which turned into DRIVEN. That one time at swim camp led, in a roundabout sorta way, to San Francisco and the South End.

A transcontinental online friendship with Donal Buckley, the Loneswimmer, produced the Marathon Swimmers Forum. The Forum made international news, and my girlfriend’s parents met me for the first time on NBC Nightly News.

And the soul-searching discussions that followed – the realization that no one was better positioned to move our sport forward than we are – ultimately produced this:

With Andrew Malinak, Donal Buckley, Elaine Howley, and the Marathon Swimmers Federation we represent, I’m proud to announce:

The MSF Rules of Marathon Swimming

If you like them, please add your endorsement here or on the Forum.

Please also see Loneswimmer’s announcement.


JANUARY 6, 2014


SAN FRANCISCO, Calif.—The Marathon Swimmers Federation, a global organization uniting, inspiring, and connecting marathon and aspiring marathon swimmers around the world, has released a set of standardized rules and principles to govern the sport of marathon swimming. These rules, which are available in full online at, codify nearly 140 years of global marathon swimming traditions into a streamlined and easy-to-use document to help swimmers around the world complete officially recognized marathon swims.

The rules were written by a core group of Federation members—Evan Morrison of San Francisco, Calif., Andrew Malinak of Seattle, Wash., Donal Buckley of Co. Tipperary, Ireland, and Elaine Howley of Boston, Mass. The co-authors spent several months developing the rules and sought input, comments, and peer-review from a wider, global group of dedicated open water swimmers. The peer review group is named in the rules document.

The rules document is intended to assist aspiring and experienced marathon swimmers, observers, event organizers, and the media to swim, organize, monitor, evaluate, and report swims according to guidelines long used by the global marathon swimming community. These rules do not supplant any existing marathon organization’s rules but may be used as a foundation for organizing bodies that want to develop swim-specific guidelines. The document includes standard marathon swimming definitions, a listing of accepted equipment, types of marathon swims, observation criteria, and standardized swimming rules.

Marathon swimming is unassisted by definition. Swims that use equipment or rules other than those outlined within the MSF rules document may be considered assisted swims.

The aim of the document is to present a complete picture of the guiding principles and widely agreed-upon standards of the sport of marathon swimming. As the sport grows in popularity, codifying rules becomes increasingly important. The co-authors hope that with the addition of these standardized rules, the sport can become more accessible to new swimmers.

About the Marathon Swimmers Federation and Forum

The Marathon Swimmers Federation is the organizational body administering the forum that was founded in early 2012 by American marathon swimmer Evan Morrison and Irish marathon swimmer Donal Buckley. The forum’s continually growing membership includes many of the world’s most accomplished and recognized marathon swimmers, as well as observers, pilots, event organizers, swim journalists, and marathon swim aspirants. The forum is an entirely voluntary and non-commercial amateur athletic discussion community that connects swimmers around the world.


For more information about the Marathon Swimmers Federation, and the forum please email .


I hate winter swimming; I love winter swimming.

In life it’s often necessary to convince oneself to do something one doesn’t want to do, in order to realize future rewards (physical, financial, emotional).

I experience this life truth in microcosm, every morning I swim in San Francisco Bay in the winter. I hate getting up early (I’m a night-owl — always have been). I hate it even more when it’s dark outside; even more when it’s cold outside. And most of all, when the reason for doing so is swimming, nearly naked, in 49-degree water.

Yet it must be done. Because no one ever says, “I really regret swimming today.” Even when the water’s 49 degrees. Perhaps especially when it’s 49 degrees.

Immersion is painful. There’s no avoiding it, even with repetition. Yet nothing makes me feel more aliveAnd there’s a reason for that: Pain is my body’s evolved, automatic response to encountering an environment that cannot sustain human life. “GTFO,” my body says at first.

When I refuse, the pain fades after a few minutes, and in its place arises a powerful warmth, which keeps the forces of death at bay (for a while). Nowhere am I more closely in touch with my life-force than while swimming in cold water.

The warmth doesn’t stop when I stop swimming. It suffuses the rest of my day in a glow of vitality.

Winter swimming is pain; winter swimming is pleasure. The latter is made possible only by the former. Winter swimming is life, magnified.

Every day is a choice. Every day an opportunity — to not just be alive, but feel alive.

aquatic park flag
The “Flag.” Aquatic Park, San Francisco, California.

Relevant Article

Sub-100 Swims

Sub-100 swims: Also known as “winter” for San Francisco open-water swimmers.

A sub-100 swim is when the water and air temperatures (in degrees F) sum to less than 100. For example, 50 degree water + 50 degree air = 100 exactly.

For our metric system friends, a sub-100 day conveniently converts to a sub-20C day, precisely.

Like much of the western U.S., San Francisco has been experiencing a bit of a cold snap lately. This morning at Aquatic Park we had 51-degree (10.5C) water combined with 37-degree (2.8C) air, for a combined total of 87 – which, I think, is a new all-time low for me.


I swam with my 6:30am group for our typical 45 minutes. Tellingly, the South End men’s showers were already running lukewarm when I arrived.

The concept of a “sub-100 swim” derives (as far as I know) from fellow South Ender Gary Emich. On his way to 1,000+ Alcatraz crossings, Gary noticed that 100 degrees combined air+water was a threshold below which his morning swims with the ASSes (which often include a dripping-wet post-swim RIB ride) became rather… challenging.

I’ve suggested on the Forum that one way to quantify how cold you are after a swim is to time how long it takes to re-warm in the sauna.

I discovered another method this morning: How many attempts does it take for me to open the combo lock on my locker? I wonder, by February will I have to ask for help? 🙂

Suit, cap, goggles: That’s all you really need.

My swim cap is tighter-fitting; my goggles are lighter-weight; and my swimsuit is constructed of chlorine-resistant polyester.

But aside from that, not much has changed from fifty years ago, when South End Rowing Club members waded into Aquatic Park cove wearing this:

Swim costume, circa 1960s. South End Rowing Club, San Francisco.
Swim costume, circa 1960s. South End Rowing Club, San Francisco.

I’d argue that the only truly essential item is the goggles… but this is a family-friendly site.

Close-up of goggles from the same display.
Close-up of goggles from the same display.

Marathon swimming resists technology more than most sports, thanks to strict guidelines on swimwear enforced in the English Channel (our Everest) – guidelines which are widely emulated around the world. Indeed it’s a point of pride among many marathon swimmers, who value the connection with our sport’s pioneers. A level playing field across decades.

I’d even call it an aestheticSuit, cap, goggles. That’s all we really need. Man, woman, and the sea. There is equipment that would make it easier, but we actively reject it. Our sport is tough, and we like it that way. 

Close-up of inscription on above display case.

SBCSA and CCSF Annual Banquets, 2013

This past weekend I attended the annual banquets of the Catalina Channel Swimming Federation (CCSF) and Santa Barbara Channel Swimming Association (SBCSA). For the past few years the two events have been scheduled for the same day, in the same city (San Pedro), with CCSF providing brunch at the Doubletree and the SBCSA providing dinner at a restaurant downtown. This arrangement seems to maximize cross-pollination between the two events – reminding everyone of the patch of ocean we share, and giving us just a little more time together.

This is my third year attending “Banquet Day” in San Pedro.

In 2011, I was a swimmer-honoree at the CCSF event, having just crossed the Catalina Channel (8:55 on August 25, and I didn’t even have to look it up). Later that day, I attended my first board meeting with the SBCSA. Rob D. and I then moved on to the Crowne Plaza bar and talked of big dreams into the wee hours.

In 2012, I returned to celebrate the new class of CCSF swimmers including my dear friend Gracie, the new record holder. Later that night at the SBCSA banquet I celebrated my own Santa Cruz Island swim and record. We watched a trailer for DRIVEN, and welcomed new board members Rob, Cherie, and Theo.

This year’s Banquet Day featured a screening of DRIVEN, now a stunning 72-minute finished product going into the 2014 film festival season. My record may have been broken, but the swim lives on. (A review is forthcoming.)

With the co-stars of DRIVEN, Cherie and Fiona. Photo by Paula Selby
Q&A with DRIVEN co-stars Cherie and Fiona. Photo by Paula Selby

Like academic conferences, these events’ value for returning attendees is mostly for the reunions and networking rather than the speeches. I was reminded that I catch up with certain people not nearly often enough (Gracie, Forrest, Mallory). I’ll remember meeting interesting new friends, Claudia R. and Kim C.

And most of all I’ll remember an unexpected and profoundly meaningful honor from my colleague Scott Zornig, whose loyalty and conviction I’ve valued these past couple months more than ever before.