The speed is displayed to tenths of a knot and seems very accurate. You can adjust the damping to one of 10 settings, from no damping to one that averages your speed over the past four minutes. (I found the default setting of 1 second a little jumpy, something I could've fixed had I read the manual in advance).

The heading, like the speed, is measured over ground, which is often more useful when sailing in tricky currents, though it does make shooting the wind difficult, the one drawback when compared to a traditional magnetic compass. Once your speed drops below a half-knot, the Velocitek stops displaying heading. The device, in speed or heading mode, will sync to a new course after each tack or jibe and then display whether the current heading is headed or lifted compared to your initial heading. (The latter feature can be turned off if not allowed by class rules).

During the Laser racing, the Speedpuck served mainly as a novelty item-wow, I'm going 4 knots! On short, college-style courses there isn't a lot of time to be staring at the speedo. Afterwards, however, I decided to see if I could glean something useful from the data. By monitoring the speed as I changed outhaul tension, I discovered that, in the moderate breeze and flat water, sailing with a tighter outhaul than I usually do was about a tenth of a knot faster. I later confirmed this observation with fleet maestro Ed Adams, a former Laser Masters world champion. In those conditions, he said, minimizing drag can be more important than creating power. The tricky part, he added, is that the boat doesn't feel as good with the outhaul pulled tighter, which can lead you to deduce that in fact more draft is better. The Speedpuck, however, showed me the truth. Next time I find myself in those conditions, I'll know what to do.

The day after sailing, I plugged the Speedpuck into the computer and used the free Velocitek Control Center software to download my track for the previous day. While watching my track run around the course, I noticed that my tacks from starboard to port really stink, that I come out of them 10 degrees low and then quickly adjust the course, which doesn't happen from port to starboard. It looks horrible on the track, and I know it isn't fast. That'll be my first order of business next time I hit the water.

Each day I race, I aim to learn one thing that makes me faster. Thanks to the Speedpuck, I picked up two. Well actually three. The final lesson of the day is that the Speedpuck has a lot to offer the dinghy and keelboat sailor, and I'll be using it more in the future. The Speedpuck retails for $339 (www.velocitek.com). The control center software is free. The $49 Speedplay software will allow you to sync and replay the tracks or two or more Speedpucks. Both pieces of software only run on PCs.