Ever wonder why bicyclists ride so close together during the Tour de France? It's all about wind resistance. The lead cyclist cuts a path through the air, and by staying close to his rear wheel, the other cyclists avoid having to cut their own "air path." This process is known as "drafting."
The same principle applies to open water swimming. By staying close behind a lead swimmer, you can save effort by "surfing" on the slipstream they've created in the water. It may not sound like much, but skilled drafting can actually reduce your perceived effort by as much as one-fifth [source: Metters].
Start by finding a lead swimmer that's the right size and speed to fit your needs. In the hours before a race, don't shy away from walking up and down the beach to check out other swimmers. Ideally, you'll want somebody that's about the same speed as you. Pick someone who's too fast, and you'll find yourself burned out before the first buoy. Pick someone too slow, and you could find yourself scrambling to find a new lead swimmer mid-race. The bulk of your lead swimmer does matter: The larger the racer is, the larger the "bow wave."
Once you've found your lead swimmer, don't draft directly behind him or her. Not only will you get repeatedly splashed in the face, but you may actually get slowed down in the eddies created by the swimmer's kicking legs. The ideal location is just beside the swimmer, with your head roughly in line with the swimmer's waist. This position also makes it easier to stay with the lead swimmer, since you can keep an eye on him or her with your peripheral vision.
Staying close is crucial in getting a good draft. Ideally, you should stay within 20 inches (50.8 centimeters) of the lead swimmer; close enough to feel the bubbles from their kicks. Just be sure not to get too close: If you're constantly bumping or hitting the lead swimmer, he or she may try to lose you by speeding up or zigzagging around the next buoy. You could also get a swift kick in the ribs. All in all, treat your lead swimmer nicely; otherwise you'll lose out on your free ride.
Near the end of a race, the swimmer will usually start to kick faster. When this happens, move up closer to the swimmer's head to steer clear of the increased eddies. You'll also be able to profit off of the increased bow wave [source: Munatones].
See the next page to find out why chlorine isn't the only difference between pools and open water.