Posts from Mar 2012

Water temperature in the Catalina Channel

Mar 04 2012

There are 14 years of publicly available data on the surface water temperature in the Catalina (a.k.a. San Pedro) Channel - via CDIP. Unfortunately, that’s all it is - data. No summary statistics, no long-term charts - nothing particularly useful if you’re just looking for a simple, big-picture view of trends and cycles in sea temperature (perhaps to inform your upcoming swim across the channel).

So I decided to make one myself:

NOAA buoys take readings every 30 minutes. Over 14 years, that works out to almost 239,000 observations. Don’t try this on an old computer! For a smoother line, I calculated a weekly average. Same data - just prettier.

Summary Statistics by Day of Year

Sea temperature varies by season, but there are also year-to-year variations. In 2010, for example, the Catalina Channel was unusually cool (even in summer). In 2006 it was unusually warm. Perhaps you’ve wondered: What is the typical water temperature on a given day of the year? If your swim is scheduled for August 15, what is the average water temperature on August 15, averaged across all years?

To answer that question, I made this chart:

Most Catalina swims take place in summer and early fall (not winter or spring), so here’s a zoomed version of the same data, for the swim season only:

So, water temps in the Catalina Channel tend to peak around August 1, and remain more or less steady through the first week of September. But even in early June and late October, the water is still “warm” by English Channel standards.

Note: It’s important to remember that surface water temps in Southern California tend to drop a few degrees as one approaches the coast, due to upwelling from the steeply sloping ocean bottom. My understanding is that this tends to happen about 3 miles from shore. So, if the buoy reading (6.5 miles offshore) is 63 degrees, the actual surface temp might actually be sub-60 during the last part of your swim.

Introducing the Marathon Swimmers Forum

Mar 11 2012

Donal Buckley and I are pleased to announce a new online community: the Marathon Swimmers Forum.

marathon swimmers forum

After a brief “quiet launch,” the forum already counts some of the most accomplished and knowledgeable marathon swimmers on the planet among its members. Whether you’re a current marathon swimmer, an aspiring one, a retired one - or just curious - we invite you to join their ranks.

Ask questions (there are no dumb ones). Discuss the latest exploits - from Dover, Manhattan, L.A., and Hawaii… to Perth, Wellington, Tarifa, and the Sea of Japan. Announce your friends’ swims and cheer them on.

Check it out at

2012 may well be the most historic, exciting year in the history of marathon swimming. Follow it on The Marathon Swimmers Forum.

A business idea: Super Swedes

Mar 24 2012

These are swedish goggles:

swedish goggles

Swedes are only goggle I’ve worn since 1992, and are among the most iconic swim gear ever. Their sleek, minimalist esthetic transcends both time and nationality. Their simple construction renders them both disposable and indestructible. Here’s an interesting history of swedes (the goggles, not the people) from Malmsten AB.

So popular are swedes among competitive swimmers that Speedo was forced to offer Speedo-branded swedes (with original Malmsten lenses, naturally) so their sponsored athletes could wear swedes at the Olympics without being in breach of contract!

Swedes’ functional minimalism cuts both ways, though. They’re cheap goggles. The lenses scratch easily. The latex straps rarely last through more than a month of regular chlorine exposure (I opt for an after-market bungee strap).

On the other end of the spectrum, there’s this:

blueseventy carbon fiber goggles

Blueseventy carbonRZR goggles

The ultimate in superfluous luxury. Carbon-fiber frames? Anti-scratch polycarbonate lenses? It can be yours for $100 - same price, incidentally, as 25 pairs of swedes. There’s an appealing sort of geek cachet to goggles made from the same material as an airplane fuselage. I’d never buy them, though. I can’t stand rubber gaskets.

But what about souped-up swedish goggles? High-quality anti-scratch lenses; chlorine-resistant straps; a nice carrying case? I might actually pay up for something like that.

Super-Swedes: a guy can dream.

Fat vs. Fast

Mar 29 2012

There’s an old saying about cold-water marathon swimming:

Either be fat, or be fast.

Is it oversimplified? Probably. Crass? Definitely. But there’s a kernel of truth worth examining. Thin swimmers have made it across the English Channel, but they’re usually fast. Slow swimmers have made it across the Channel, but they’re usually… carrying a healthy layer of bioprene.

The common factor: Core temperature must be preserved. Either generate heat, or retain it. Fast swimmers are good at generating heat. Fat swimmers are good at retaining it.

In the English Channel (from what I gather), it’s considered prudent for non-overweight swimmers to put on some weight, even if they’re “fast.” A Channel attempt is expensive and, unless your name is Petar Stoychev, just getting across is the main priority. Bioprene increases the probability of success.

But at what cost? How much does the extra weight slow you down? Swimming is a gravity-less activity, so obviously it matters less than in running or uphill cycling. Further, the flotational benefits of fat may improve your body position in the water.

In running, the rule of thumb is 2 seconds (faster) per mile per pound (lost). Is there a similar rule of thumb for swimming?

Out of curiosity, I asked my coach to estimate the benefit of losing 10 pounds of body fat on threshold pace per 100m (assuming stable fitness & muscle mass). He said 2-3 seconds per 100m. Some quick conversions: 32-48 seconds per mile, 10-16 minutes per 20-mile channel swim. Or, for an apples-to-apples comparison with running: 3.2-4.8 seconds per mile, per pound.

And actually… that accords fairly well with my own experience. I do a lot of threshold (a.k.a. CSS) training - so I’m intimately familiar with my basic pace per 100m. Also, my weight has fluctuated a bit in the past couple years - giving me some data to draw on.

Can we do better than a rule of thumb? Scientists being scientists, it turns out someone has actually studied this question. In a paper published in the Journal of Strength and Conditioning Research, Ilka Lowensteyn and two colleagues artificially varied the body fat of competitive swimmers by fitting them with weighted latex pads under a spandex triathlon suit. The swimmers were timed at 50-yard sprints at various weights.

Lowensteyn et al. estimated the swimmers were slowed by 0.2 seconds per 50 yards, per pound. That’s 4 seconds per 100, per 10 pounds - not far off Coach AB’s estimate. And it makes sense there would be a larger effect in a sprint (compared to threshold pace), because in water, drag increases exponentially with speed.

Bottom line: Let’s say you gain 20 pounds for your English Channel attempt. You might be looking at about an extra half-hour in the water. Given the thermal-protective benefits of those 20 pounds, though, it seems like a small price to pay.

Very Important Announcement

Mar 31 2012

This summer I will attempt something truly audacious… groundbreaking… unprecedented… game-changing.

I will attempt to (ahem…) cross the English Channel. Not once, not twice or even thrice. Ten times. Consecutively. 210 miles without stopping.

Needless to say, this has never been achieved by a swimmer. Which is not to say I’ll be swimming. Indeed, I’ll be doing everything possible in order to not swim. Actually swimming 210 miles would be far too difficult.

I will be aided in my quest by several important tools:

  1. A monofin. I’m thinking the Competitor model from FINIS looks pretty sweet.

  1. Paddles. But not just any old paddles. Special paddles. My usual training paddles (Lenox among the proud sponsors of my “swim.”

  2. A drysuit. Because I don’t want any part of my body to actually touch the water. Did you know, the English Channel is apparently cold!

  1. Finally - because 210 miles is still a long way to “swim,” even with a monofin, dinnerplate paddles, and a drysuit - Honda Marine will be donating a 225hp outboard motor to my effort.

How will I use this engine, you ask? Here’s the kicker: I’ll be working with the fine folks at UCLA Medical Center (these are people with not only MDs, but PhDs too!) to develop the very first boat-engine prosthesis for humans. That’s right - I will be permanently grafting a boat engine to my backside! Awesome, right?

No more Maxim - only 93-octane unleaded for this guy!

I haven’t quite figured out yet how my boat-engine prosthesis will work with the monofin, but… I’m sure we’ll work out all those details later.

Finally, I’m pleased to announce that I’ve been in contact with the Guinness Book of World Records and the International Marathon Swimming Hall of Fame, who have both assured me that, if I am successful, my feat will be entered into the books as the first monofin-aided, dinnerplate-aided, drysuit-aided, outboard motor-aided “decuple” (that means 10x) crossing of the English Channel.

I’m hoping that the media attention my attempt will generate will inspire others to follow in my footsteps. For the person who wants to swim - but doesn’t want to, you know, actually swim - this is a revolutionary solution. My aim is nothing less than to create a new industry.

Because, let’s face it: Swimming is hard. Who can be bothered?