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ORC — all-purpose time-on-time (APHT), the IRC-equivalent option

ORC Rating Systems 403.3: CT = ToT × ET, where ToT = 600 / ToD. APHT is the certificate's all-purpose single number; a higher APHT (faster boat) gives time away.

APHT values from the boats' real 2026 IRL ORC certificates:
  Impetuous (Corby 25)  APHT 0.9631
  Mojo (J-80)           APHT 1.0089

Start 14:00:00. Mojo crosses two minutes ahead but corrects out behind:
  Mojo:      finish 14:58:00  ET = 3480 s  CT = 3480 × 1.0089 = 3510.97 → 3511 → 2nd
  Impetuous: finish 15:00:00  ET = 3600 s  CT = 3600 × 0.9631 = 3467.16 → 3467 → 1st

Corrected times round half-up to whole seconds (ORC 401.2 — the same
convention as IRC scoring here).

Race arithmetic

Series standings