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.

8 thoughts on “The Chas Lap”

  1. Looks like a great swim.
    Nice image.
    It may be that things have changed or that my memory is just clouded with age… I believe in the 70’s there used to be a buoy somewhere between your Muni Pier mark and Goals Post mark. Is it not there? My memory is that you would swim to the ship’s anchor chain, to the buoy, to the flag and back in along the shore to make a mile. Is that not the way it is now?
    (BTW, you’re all just Southies to me.)

    1. Hey Anthony! Currently there’s no buoy where you describe. There’s usually a buoy at the Opening (though it recently moved off its anchor). There’s another one east of the Jacuzzi… i think the Dolphin Club calls this “Bad Betty.”

      Re: distance… even a tight circumnavigation of the Cove is only about 0.85 miles.

      1. From Josh Sale:

        Evan, my understanding is that “Bad Betty” is the SE name for that marker and not the Dolphins. Story has it that it was named after a Dolphin named Betty who swam beyond it (bshe was a bad Betty) and was thrown out of the club for her transgression. She of course would be very welcome at the SE.

  2. Guess the cat’s out-o-the bag. Had to happen eventually. Great job with the diagram Evan. I would only add a couple of things that are important to remember when swimming “outside” of the cove along the SF waterfront.

    1. HEADS UP! Always stay close (10 feet or closer) to the break wall and the piers to avoid random boat traffic. Cut inside (towards the shore) in the area between Muni Pier and the east Fort Mason pier which will keep you protected from the straight line boat path between Muni Pier and Ft Mason. While breathing, continually scan the water around you for boats. Be particularly careful at the Hyde Street marina (creakers) opening and at the Gas House opening. Remember that boat pilots will have a difficult time seeing you even in smooth water and they won’t be expecting you… ever!

    2. EVEN THE FASTEST, STRONGEST SWIMMERS CAN HAVE A PANIC ATTACK. I’ve had one myself years ago at the conner of Ft Mason’s east pier. Only once for me and I learned my lesson. Don’t go out of the Cove ever without taking along your very best AWARENESS. Always have a Plan “B” in mind should you encounter any kind of obstacle. If you can’t swim against the current then you’ll have to swim with it but to where and get out where? Make certain you can answer these questions before you commit yourself.

  3. Hi Evan! This is one of Chas’ daughters here. Thank you so much for documenting the aspects of the Chas Lap! I believe you captured the essence of both the lap and the Chas and I want you to know how much I appreciate this… My dad’s swim/ life advice he explains at the bottom is so him and so true. Something my sister and I still learning from him. Thank you!!

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