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ECHO — Irish Sailing 2022 ECHO Guide for Clubs, page 2 worked example

10-boat single race with α = 0.25 (the IS-recommended 75/25 split for club racing).
Reproduces the canonical worked example from the Irish Sailing 2022 guide. Start at
12:00:00; T_E values from the guide are scaled to seconds (T_minutes × 60).

Engine output matches the IS Performance Index formula exactly:
  PI_i = ΣH_S / (T_E_i × Σ(1/T_E))
  new_H_i = (1 − α) × H_i + α × PI_i

Three rows in the IS guide table differ from the formula's true output:
  Row 6 (T_E=70, H=1.000): IS table shows new_H=0.952; formula gives 0.970.
      The PI value of 0.879 is correct; the printed new_H is a typo.
  Row 3 (T_E=66): IS table prints PI=0.937; formula gives 0.933.
  Row 9 (T_E=61): IS table prints PI=1.006; formula gives 1.009.
      (Boats 2 and 9 share T_E=61, so their PI must be identical;
       Boat 2's printed PI=1.009 matches the formula.)

The engine matches the formula in every row. The expected new_H values below
are the formula-correct values — see project_is_2022_echo_table_typo memory.

Computed reference values:
  ΣH_S            = 10.221
  Σ(1/T_E)        ≈ 0.00276745386 (in 1/seconds)
  CT_avg          = 3706.6  (mean of rounded per-boat CTs)

Ranks by corrected time ascending: 7, 10, 8, 1, 4, 9, 2, 5, 3, 6

Race 1

Series standings