Sail Tactician is a racing app for the iPhone and Apple Watch: start-line timing, live wind shifts, VMG, session recording, and post-race analysis. It works on the phone alone, or with the watch as the on-water display.
Racing is where it goes deepest, but nothing needs a race committee. Record a Training session to drill tacks and gybes with coaching, or a Cruise to log a day out — you still get the full track, the analysis, and your trends across a season. Set your usual choice under Settings → Race → Default Session Type.