You can measure your speed, course, and loges (SOG, COG, LOG)
Place an app complication on your favorite watch look and take your GPS data whenever you need it. 4 different screens for GPS data.

COG - Course Over Ground
Is the actual direction of progress of a vessel, between two points. Plus your speed in knots and logged distance in nautical miles on the same screen.

SOG - Speed Over Ground
Is the speed of the vessel relative to the surface of the earth. Plus maximum and average speed on the same screen.

LOG - the automatic record of your logs in nautical miles. Plus current speed and trip time on the same screen.

Combined Data Display - all information on one screen.
SOG - speed over ground
avg kn - average speed in knots
max kn - maximum speed in knots
COG - course over ground
log nm - logged nautical miles
time - trip time