During the WWDC keynote last week, Apple announced that the Apple Watch’s next OS (watchOS 4) will allow the device to establish a direct Bluetooth connection to other devices such as blood glucose sensors (for people with diabetes) or smart tennis rackets (yawn).

Or surfboards. Wait. What? Actually, an Apple Watch with a direct connection to a sensor mounted on a surfboard could prove to be a game changer for some surfers.

Apple VP Kevin Lynch briefly mentioned an Apple Watch app called Sessions by a small Green Bay, Wisconsin, company called Xensr. The app works with a sensor (the $200 Xensr Air 3D) mounted on the surfboard to capture both wave data and the performance of the surfer.

The GPS radio inside the mounted sensor device, says Xensr founder David Troup, allows it to act as a “wave buoy” that collects all kinds of data about the waves in the area, and can even help forecast future waves. The gyroscope in the device tracks all motions of the surfboard; the number, locations, and sizes of waves surfed; the height of jumps off waves; and the lengths of waves surfed.

Until now Xensr users have waited to get back to shore to check out wave and performance data on their phone screen. That’s because the sensor has to sync with a phone to transfer the data. But the new direct Bluetooth support in watchOS 4 will let surfers see the data (in small bits) on their wrist while they’re out on the board, paddling between waves. The data might help a surfer adjust their game in situ to catch more waves and ride them longer.

Example: A big part of the art of surfing is sensing the best time—and best location on the curve of the wave—to get up on the board. This is called the takeoff point, and picking the best ones is probably the hardest thing about surfing. The Xensr app might add some science to the art.

“It’ll give me a map of all my takeoff points on all my best waves,” Troup told me. That knowledge could inform the choice of takeoff point on future waves. “I may get two or three more turns on that same wave just because of the takeoff point,” Troup says.